THE PALEOECOLOGY AND FLORA OF THE BLACKHAWK FORMATION (UPPER CRETACEOUSI FROM CENTRAL UTAH DISSERTATION FOR THE DEGREE or Ft. D. MICHIGAN STATE UNIVERSITY LEE ROSS PARKER 1976 _ Illlllllllllll‘lll'vflllfllflllllllll' a g 3 293 10631‘ 7658 This is to certify that the thesis entitled THE PALEOECOLOGY AND FLORA OF THE BLACKHAWK FORMATION (UPPER CRETACEOUS) FROM CENTRAL UTAH presented by LEE ROSS PARKER has been accepted towards fulfillment of the requirements for Ph. D. degree in Botany and Plant Pathology Major professor 0-7639 '1 u “,1“ -vl-n. , ‘..I\ f y. 9.. J 909. g 9 1999 A . a .—=’11£__D m ;" 1 1 5" u..- " 'na. '- . 4 P“... ‘u. ' \ Thn‘ -. ~. \ ‘.._' \,,; ~Ll_ . ‘ 'o. _.. ' : ABSTRACT THE PALEOECOLOGY AND FLORA OF THE BLACKHAWK FORMATION (UPPER CRETACEOUS) FROM CENTRAL UTAH by Lee Ross Parker More than 7,400 fossil plant specimens, representing 118 species, were collected from the Upper Cretaceous Blackhawk Formation in Salina and Straight Canyons of the Wasatch Plateau. These plants include one thalloid liverwort-like plant, one club moss-like plant, fourteen ferns, twelve gymnosperms of various types, and eighty-six angiosperms. Angiosperms are represented by 5 monocotyledons and 81 dicotyledons. Eight ferns and 31 unidentified dicotyledons are thought to be species not previously described. This is one of only 3 large Upper Cretaceous floras of the Upper Santonian-Lower Campanian Stage described from North America. The western portion of the Blackhawk Formation consists chiefly of fluvial lenticular sandstones, siltstones, shales and coals deposited on a broad floodplain west of the Cretaceous Interior Seaway. Three major types of sedimentary environments are differentiated here: peat-forming swamps, bottomlands, and river point bars. The swamp environment supported a plant community dominated by two trees: Sequoia cuneata, an evergreen conifer; and Rhcmmites eminens, a decidu- ous angiosperm. Subordinate trees consisted of several other conifers and angiosperms including Pro tophy Z Zoc Zadus p0 Zymor'pha , Brachyphy Z an macrocarpwn and PZatanus raynoldsii. Geonomites imperialis, a small Lee Ross Parker ‘palm, was abundant near'swamp margins; and Cissus marginata, possibly a woody vine, occurred in most swamps. Herbaceous angiosperms were lacking but an understory was composed of the ferns Cyathea pinnata and OnocZea hebridica. Two aquatic plants, a water lily, Nymphaeites dawsoni, and water chestnut, Trqpa pauZuZa, were present. The bottom- land communities were co-dominated by four angiosperms, Cercidiphyllum arcticum, PZatanus raynoldsii, DryophyZZum subfolcatum, and Unknown dicot 2. Several other angiosperms were present as subordinant trees, but conifers were rare and unimportant. The palm, Geonomites imperialis, made up at least a portion of the shrubby understory. Two vines existed in this community, Manispermum dauricumoides and Cissus marginata. Ferns seem to have been the only herbaceous plants. River point bars apparently did not support a diverse plant community. Instead, all specimens collected in these sediments seem to have been transported some distance before burial. The conifer Araucarites sp. was found in some abundance in widely separated point bars but was not collected in swamps or bottomlands. It probably was moved downriver from the upper delta plain environments or possibly from the piedmont. The Blackhawk floodplain communities are different in several ways from those communities which exist today but do have certain features similar to the extant plant communities of the Lower Mississippi River Valley. Several independent methods have been used to determine the paleo- climate in which the Blackhawk plant communities lived. The most significant is the analysis of leaf physiognomy including the high portion of leaves in the microphyll and notophyll leaf size classes Lee Ross Parker (If Raunkiaer, and the large number of leaves with entire margins. All the methods suggest that the climate was warm and seasonal, most likely of the "subtropical-seasonally dry" type. Descriptions of the ecologically important non-angiospermous plants are given and include the following: the ferns AspZenium dicksonianum, Cyathea pinnata, OnocZea hebridica, Osmunda hoZZicki, and Unknown fern 1; two unassigned gymnosperms Nageiopsis sp. and Podozamites sp.; and the conifers Araucarites sp., Brachyphyllum macrocarpum, Mbriconia cyclotoxon, ProtophyZZooZadus polymorpha, ProtophyZZocZadus sp. 2, Sequoia cuneata, and Widdringtonites reichii. Many problems still exist with the characterization of fossil angio- sperms, and with the exception of the palm Geonomites imperialis, they have been omitted from the descriptions. Sequoia cuneata was represented by more than 500 specimens, including two types of foliage leaves, cuticle with epidermal cell impressions, ovulate and staminate cones attached to foliage, and seeds. Enough information is added to its description that there is little doubt of its relationship to the genus Sequoia rather than to MEtasequoia as had earlier been suggested. THE PALEOECOLOGY AND FLORA OF THE BLACKHAWK FORMATION (UPPER CRETACEOUS) FROM CENTRAL UTAH By Lee Ross Parker A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Botany and Plant Pathology 1976 ACKNOWLEDGEMENTS Grateful acknowledgement is extended to a number of persons for help in this study. These include first of all Aureal T. Cross, who as my major professor, spent several days in the field and numerous hours in the laboratory with me where he provided invaluable sugges- tions, encouragement and criticism in all areas of the study. In addition, he spent a great deal of time and effort in the preparation of this manuscript. William D. Tidwell of Brigham Young University also was of great help in field and laboratory work. J. Keith Rigby and James A. Jensen both of Brigham Young University and Homer Behunin pointed out several specific collection sites in Salina Canyon. Assistance of various types, including heavy field work, was provided by Maron and Adeline Parker, my parents, John and Arba Duncan, my wife's parents, and Glenn M. Parker, John G. Duncan, Scott Russon, John D. Jolley and my wife, Lana. Erling Dorf of Princeton University kindly invited me to use his "Catalogue of Mesozoic and Early Cenozoic Plants of North America" in the identification of the fossil specimens. David Dilcher of Indiana University demonstrated his technique of isolating fossil leaf cuticle. Ralph Taggart was particularly con- structive in evaluation of several portions and he, Peter Murphy, and Robert Anstey provided invaluable suggestions, particularly in the paleoecological analysis and in the preparation of this manuscript. Peter Carrington prepared the reconstruction of Braohyphyllum ii rmacrocarpum and.Moriconia cyclotoxon, and Dinah Herron prepared the reconstruction of Sequoia cuneata. This study was supported in part ‘by G. A. #429 "Paleobotanical interpretation of environments in the Rocky Mountain Cretaceous" to Aureal T. Cross. iii TABLE OF CONTENTS L I ST 0F TABLE S I I I I I I I I I I I I I I I I I I I LIST OF ILLUSTRATIONS . . . . . . . . . . . . . . . . . INTRODUCT I ON I I I I I I I I I I I I I I I I I I I I I I GEOLOGIC SETTING OF THE REGION . . . . . . . . . . . . . Phys iography I I I I I I I I I I I I I I I I I I I Geologic History . . . . . . . . . . . . . . . . . THE BLACKHAWK FORMATION . . . . . . . . . . . . . . . Sedimentation and Stratigraphy . . . . . . . . . . Lithologic Character . . . . . . . . . . . . . . . Age . . . . .o. . . . . . . . . . . . . . . . . . . RELATED GEOLOGICAL AND PALEOBOTANICAL STUDIES . . . General Geology . . . . . . . . . . . . . . . . Coal . . . . . . . . . . . . . . . . . . . . . . . Paleobotany . . . . . . . . . . . . . . . . . . . . Palynology .-. . . . . . . . . . . . . . . . . . . Regional Paleoecology . . . . . . . . . . . . . . . COLLECTIONS AND METHODS OF STUDY . . . . . . . . . . . . Collections . . . . . . . . . . . . . . . . . . . . Field Methods . . . . . . . . . . . . . . . . . . . Curatorial Procedures . . . . . . . . . . . . . . . Photographic Catalog . . . . . . . . . . . . . . . Laboratory Techniques . . . . . . . . . . . . Cuticle preparation and study . . . . . . . . Palynologic examinations . . . . . . . . . . . Megasc0pic leaf preparations -- excavation . Identification of the specimens . . . . . . . . . . THE BLACKHAWK PLANTS AND FLORISTIC RELATIONSHIPS . . . . Plants in the Blackhawk Formation . . . . . . . . . Relationship to Other Floras . . . . . . . . . . PALEOECOLOGY . . . . . . . . . . . . . . . . . . . . . Identification of Blackhawk Fluvial Environments of Deposition . . . . . . . . . . . . . . . . Correlation of the Fossil Plants with Environments of Deposition . . . . . . . . . . . . . . . . Quantitative Paleoecology . . . . . . . . . . . . . iv Page vii ix (”LBW 10 10 12 l6 l7 17 20 21 23 23 25 25 29 29 31 31 31 32 33 33 35 35 39 43 43 47 49 ‘~ ‘u. TABLE OF CONTENTS (Continued) IHTVIFEHHIENT OF THE BLACKHAWK SWAMPS . . . . . . . . . . . .Arborescent Plants . . . . . . . . . . . . . . . . . Shrubby Understory and Vines . . . . . . . . . . . ‘Herbaceous Understory . . . . . . . . . . . . . . . . Aquatic Plants . . . . . . .... . . . . . . . . . . 'Palm Thickets . . . . . . . . . . . . . . . . . . . . Swamp Conifers . . . . . . . . . . . . . . . Seedling Growth, Water Fluctuation and Water Depth . Swamp Soil . . . . . . . . . . . . . . . . . . . . . Size and General History of Fluvial Swamps . . . . . The Cox Swale Fluvial Paleoswamp . . . . . . . . . . Sedimentary history . . . . . . . . . . . . . . Flora of the Cox Swale paleoswamp . . . . . . . ENVIRONMENT OF THE HARDWOOD BOTTOMLAND COMMUNITY . . . . . Arborescent Plants . . . . . . . . . . . . . . . . . The Shrubs and Vines. . . . . . . . . . . . . . . . . The Herbaceous Understory . . . . . . . . . . . . . . The Bottomland Soil . . . . . . . . . . . . . . . . . Alternation of Bottomland and Swamp Environment at Taylor Flat . . . . . . . . . . . . . . . . . TFHE ENVIRONMENT OF THE BLACKHAWK POINT BARS . . . . . . . Transported Plant Remains . . . . . . . . . . . . . . In Situ Plant Remains . . . . . . . . . . . . . . . . IPROBABLE DECIDUOUS PLANTS . . . . . . . . . . . . . . EVIDENCE OF ANIMALS I I I I I I I I I I I I I I I I TEHE WESTERN HIGHLANDS, FLOODPLAIN AND RIVER SYSTEMS . . . Highlands and Floodplain . . . . . . . . . . . . . . The Rivers . . . . . . . . . . . . . . . . . . . . . The Periodicity of Flooding . . . . . . . . . . . . . THECOASTALNON-FLUVIALSWAMPS. . . . . . . . . . . . . . PALEOCLIMATIC INTERPRETAT IONS . . . . . . . . . . . . . . Fossil Leaf Physiognomy . . . . . . . . . . . . . . . Entire leaf margins . . . . . . . . . . . . . Leaf nervation, thickness, drip points, vein patterns and epidermal features . . . . . . Leaf-size analysis . . . . . . . . . . . . . . . Problems associated with using leaf physiognomy Application to this flora . . . . . . . . . . . A comparison of the physiognomy of swamp and bottomland leaves . . . . . . . . . . . Page 57 58 62 64 68 69 72 74 75 77 79 79 88 91 91 94 95 96 97 106 106 110 112 115 118 118 118 121 123 126 126 126 127 128 130 131 132 TABLE OF CONTENTS (Continued) Climatic Requirements of Living Relatives . . . . . Seasonality of the Blackhawk Climate Climate Suggested by Other Cretaceous Summary of Paleoclimatic Information SYSTEMATIC PALEOBOTANY . . . . . . Asplenium dicksonianum . . . Cyathea pinnata . . . . . . . OnocZea hebridica . . . . . . Osmunda hoZZicki . . . . . .- Unknown Fern l . . . . . . . Araucarites sp. . . . . . . Brachyphyllum macrocarpum . . Mbriconia cyclotoxon . . . . Nageiopsis sp. Podozamites sp. . . . . . ProtophyZZocZadus polymorpha ProtophyZZocZadus sp. 2 . . . Sequoia cuneata . . . . . . . Widdringtonites reichii . . . Geonomites imperialis . . . . APPENDIX I COLLECTION LOCALITIES Floral Studies APPENDIX II OTHER FOSSIL LEAF IMPORTANCE INDEX CONSIDERATIONS APPENDIX III RAINFALL CALCULATIONS APPENDIX IV DICOTYLEDONS IN EACH OF THE FLOODPLAIN ENVIRONMENTS . . . APPENDIX V PHYSIOGNOMY OF LEAVES FROM A MICHIGAN FOREST . APPENDIX VI PHYSIOGNOMY OF LEAVES IN THE BLACKHAWK FLORA LIST OF REFERENCES . . . . . PLATES I I I I I I I I I I I I I I vi Page 134 135 137 138 141 142 143 144 146 147 149 152 156 159 161 163 166 167 177 178 182 185 188 189 192 194 196 218 Tafixle 1. 10. LIST OF TABLES The species of the Blackhawk flora. The number of specimens of each species are indicated under the site in which they were collected . . . . . . . . . . Criteria used for the identification of fluvial environments in the Blackhawk Formation . . . . . . . The type of floodplain environments suggested for each of the fossil collection sites . . . . . . . . . The 43 most important species in the Blackhawk flora. The number of specimens of each species collected within each environment is shown. The collection sites are grouped together into the 3 major floodplain environments . . . . . . . . . . . . . . . The relative frequency, relative density, and Importance Index of each of the important Blackhawk species within the three floodplain environments . . . . The species and number of specimens collected in the Taylor Flat collection sites. The sites have been arranged in stratigraphic order such that the lowermost is on the left and the uppermost is on the right . . . . . . . . . . . . . . . . . . . . . . Percentages of all 82 Blackhawk dicotyledon species which show selected aspects of leaf physiognomy including size. This information is taken from Appendix VI. . . . . . . . . . . . . . . . . . . . Percentages of dicotyledon species in Blackhawk Swamp, Bottomland and Point Bar Environments having the same leaf characteristics as those in Table 7 . . . . A comparison of percentages of leaves in the leaf size classes of selected Cretaceous, Tertiary and extant floras. All measurements were made by the author from published photographs except those of the late Tertiary floras which were measured by R. E. Taggart . A comparison of the values from the two Importance Indices . . . . . . . . . . . . . . . . . . . . . . . vii Page 36 46 48 50 55 100 130 133 140 187 LIST OF TABLES (Continued) Tadile 11. 12. 13. 14. Page Dicotyledons in each of the floodplain environments . . . 189 A.summary of the dicotyledons which appear to be ‘ characteristic of each of the environments. The taxa numbers refer to those listed in Table 11 . . . . . 191 Leaf Margins and Raunkiaer Leaf Size classes of the Woody Dicotyledons of Sanford Natural Area, Michigan State University, East Lansing, Michigan. The species have been determined by Beaman-(l970) and all measure- ments were made by me from herbarium specimens . . . . . 192 Those dicotyledons of the Blackhawk Formation which have entire margins, pinnate nervation, coriaceous texture, and drip points. The average size of the leaves in cm2 and Raunkiaer leaf size classes is also indicated. When there was a possibility that the average size of the leaves could be larger if more had been measured, the leaf size class indicates a range from one class to another . . . . . . . . . . . 194 viii v . LIST OF ILLUSTRATIONS Figure Page 1. Index map of fossil plant collection localities in the Wasatch Plateau. The areal extent of the Blackhawk Formation is indicated by stippling . . . . . 3 2. Index map showing major physiographic features in the Wasatch Plateau region. Note the sinuous escarpment of the Wasatch Plateau and Book Cliffs for nearly 200 miles . . . . . . . . . . . . . . . . . . . . . . . 6 3. Stratigraphy of the Blackhawk and related formations of the western Book Cliffs area (after Young, 1966) . . 14 4. Stratigraphic correlation of the collection sites at the localities indicated in Figure 1 . . . . . . . . . . 26 5. The major Cretaceous floras of North America showing the approximate relative stratigraphic range of the collection localities within the formations, the number of species in each flora and references to the floras and stratigraphy. The Blackhawk study is included . . . . . . . . . . . . . . . . . . . . . . 40 5- The percentage of total specimens collected of the most important fossil plants in each of the three Blackhawk floodplain environments. They are listed in phylogenetic order within each of the environ- ments . . . . . . . . . . . . . . . . . . . . . . . . . 51 7- (A) Diagramatic reconstruction of units M, N, and O at the Water Hollow Road collection locality indicating the relative size and position of the buried palm trunks (Geonomites imperialis) and palm leaf mats in units M and O. (B) Photographs of the palm trunks in unit 0, viewed from below as they are exposed in the bottom of an overhanging ledge . . . . . . . . . . . 70 8. Generalized stratigraphic section at the Cox Swale collection locality. The lithologic units have been designated letters A through H, the fossil collection site is indicated, and fossil tree stump casts are shown . . . . . . . . . . . . . . . . . . . . . . . . . 80 ix nel¢~: ~.1 I. u‘o LIST OF ILLUSTRATIONS (Continued) Figure 9. 10. 11. 10. 11. Vertical tree trunk casts in the swamp sediments at Cox Swale. The Units A through H indicated here are the same as those in the generalized stratigraphic section in Figure 8 . . . . . . . . . . . . . . . . . Alternation of bottomland, swamp and channel deposition at the Taylor Flat locality. Indicated are the collection sites in the lithologic units, the letter designations, (A through Q) of the units, the presence of fossil stump casts and the relation of this section to Interstate 70 and a dirt access road . . . . . . . The lensy nature of the fluvial in-channel point bar sandstones within the middle region of the Blackhawk Formation at Pipe Springs in Salina Canyon . . . . . . Figures 1 through 3 . . . . . . . . . . . . . . . . . Figures 1 and 2 . . . . . . . . . . . . . . . . . . . Figures 1 through 6 . . . . . . . . . . . . . . . . . . Figures 1 through 9 . . . . . . . . . . . . . . . . . . Figure 1 I I I I I I I I I I I I I I I I I I I I I I I Figures 1 through 10 . . . . . . . . . . . . . . . Figure l . . . . . . . . . . . . . . . . . . . . . . . . Figures 1 through 6 . . . . . . . . . . . . . . . . . Figures 1 through 13 . Figure l . . . . . . . . . . . . . . . . . . . . . Figures 1 through 4 . . . . . . . . . . . . . . . . . . Page 82 99 107 218 . 220 222 . 224 226 228 230 232 . 234 236 238 "v. I.-. II ‘5. IN TRODUCT ION The Blackhawk flora from the Wasatch Plateau in central Utah is one of only three large Upper Cretaceous floras of the Upper Santonian-Lower Campanian Stage described from North America. It is composed chiefly of dicotyledonous plants, but includes several ferns and gymnosperms. Analysis of the occurrence of these plants in the sandstone, siltstone, and shale facies provides new evidence about the several types of c<'->astal plain plant communities which occupied the area. A study of the kinds of plants present and certain of their morphological features indicates the climatic conditions which existed during that time. The Matawan flora (Berry 1903a, 190391904, 1916) and the Magothy flora (Berry 1906, 1908, 1916; Miller 1974) both of the New Jersey-Delaware- MaI‘yland area are the only other large floras reported adequately to date which are interpreted as contemporaneous with the floras found in the Blackhawk. Although these two Atlantic coastal plains floras were Separated from the Blackhawk by a broad interior sea which was several 1“\lndred miles wide, they were probably at a comparable latitude even tLhOugh the North American continent has shifted somewhat since the Upper Cretaceous (Raven and Axelrod, 1974). Several interesting floristic 81Jnilarities exist between them. Other fossil floras of this Stage are knOwn to exist but either a significant number of specimens have not been collected at this time (e.g., Knowlton, 1900; Berry, 1929; Bell, 1963; Arnold & Lowther, 1955), or they are thus far not published in detail (Smiley, 1966, 1969). This study forms a link between the large floras of the lower Upper Cretaceous (Cenomanian and Turonian Stages) such as the Dakota, Tuscaloosa, Frontier and Raritan, and the uppermost Cretaceous floras (Maestrichtian Stage) such as the Ripley, Fox Hills, Lance, Vermejo, Laramie, and Denver. The Blackhawk flora described here is a composite of several small florules collected at six main localities within the Blackhawk Formation, These occur in Salina and Straight Canyons on the southern and eastern escarpments of the Wasatch Plateau. The collection localities are indicated on Figure l, where the areal extent of the Blackhawk Formation in the Wasatch Plateau is also shown. Each of these collection localities is described in Appendix I. A number of papers have been published on various aspects of the coal, stratigraphy, and sedimentary features of the Blackhawk Formation, but the description and interpretation of fossil plants has received only passing attention. Plant microfossils, however, have been used to correlate and interpret certain Blackhawk coals. They have also been used extensively within the region in studies involving Upper Cretaceous marine and brackish water sediments. The Blackhawk Formation is very fossiliferous throughout its exposure. Many specimens have been collected from outcrops and from within coal mines by various individuals. At the present time, small cOllections are housed in museums at Brigham Young University in Provo, the University of Utah in Salt Lake City, Carbon County Museum in Price, and at Dinosaur National Monument at Vernal. It is possible thatadditional area museums also have specimens. Many local "rock “is . last: i k, 517‘} I 11.51 l .. .. raight; «0" t I" “13""; h; 1;" o ”yon ' . We...‘ '5 1 7} I"g 1 Utah 2 3? Orange- 9 ville 3719?. ." 3 qkilometers , -. 'wfii‘t' . ‘19." 6 miles j COLLECTION LOCALITIES 1 Cox Swale 2 Black Diamond Mine (abandoned) 3 Knight Mine (abandoned) 4 Taylor Flat 5 Pipe Springs 0 Water Hollow Road Ferron Figure 1. Index map of fossil plant collection localities in the Wasatch Plateau. The areal extent of the Blackhawk Formation is indicated by stippling. shops" often display well-preserved specimens. A larger collection is now housed at the U.S. National Museum. The collection examined in this report is composed of about 7,400 specimens, mostly leaf compressions, on 1,200 individual blocks, and is the largest plant fossil collection known to have been made in the Formation, or in the Wasatch Plateau. It is currently housed in the Fossil Plant Collection of the Herbarium at Michigan State University. GEOLOGIC SETTING OF THE REGION Physioggaphy The Wasatch Plateau is a gentle, westward dipping monocline of Upper Cretaceous and lower Tertiary rocks, the eastern edge of which forms a sinuous escarpment extending for nearly 70 miles (110 km) from the Price River, southward to Salina Canyon, Utah. The Wasatch Plateau escarpment and Book Cliffs intersect at Spring Canyon to form a nearly continuous series of faceted cliffs from central Utah eastward into Celorado, and are a major physiographic feature of the region (Figure 2). The cliffs, which circumscribe the west, north and northeast sides of the San Rafael Swell, have been formed by headward erosion in strata of differing erosional resistance in the arid climate. Remnants of Padiment surfaces and bajada-like deposits extend high up on the flanks of the cliffs and may be seen at several locations (Young, 1966; and fZleld notes with A. T. Cross, 1970). The sinuousity of the cliffs is tflne result of local influences, chiefly faulting, such as the Valley, Gordon Creek, Joe's Valley, Musinia and Water Hollow Fault zones (Doelling, 1972), and several permanent and ephemeral streams, such as the Price River, Huntington Creek, Cottonwood Creek, Ferron Creek, lhfidy Creek, Ivie Creek, and Salina Creek, some of which follow major faults through portions of their courses. Others are independent of the faulting patterns. .moaaa com sauna: new mmmwao Moon was smoumam soummmz ozu mo udoBQHMUmo mooocauaoo happen poo encodes _ .N ouawwm one ouoz .EOAwou smoumam noummos ago as monoumom canamquAmxne Henna wafieonm ems xopaH Dfim w zrm a north-south topographic barrier between the Basin and Range 1?]:ovince and the Colorado Plateau Province. Exposures in the Wasatch Plateau include the slope-forming Sediments of the uppermost Mancos Shale (Blue Gate and Masuk Members Separated by the Emery Sandstone), the cliff-forming Star Point, Blackhawk and Price River Formations, all of Cretaceous age; the North Horn Formation, which transcends the Cretaceous-Tertiary boundary; and the Lower Tertiary Flagstaff Formation. In the area of this study coal is being mined from the Blackhawk Fbrmation and Ferron Sandstone. The Wasatch Plateau, trending in a general north-south direction, nearly parallels the strand line of the ancient epicontinental sea, um! o'n- . ..-‘ ”I I I -I b ‘c . ,.. III I I... I o. . I in. __ ‘r I . ‘- . n 'b ‘- I.. while the regional east-west trend of the Book Cliffs is approximately normal to the strand line. This orientation, the extensive dissection and height of the steep cliffs, the nearly continuous exposures of fluvial and transitional coastal plain and near-shore marine features, provide an excellent display for sedimentary and paleoecological s tudies . Geo logic His tori Spieker (1949a, 1949b), Young (1966), Armstrong (1968), McGookey (1972), and Hintze (1973) have described the regional geologic history during the Cretaceous Period, pointing out that as the Western Interior eI>icontinental sea expanded westward in the Early Cretaceous (Albian) its margin fluctuated in a transgressive-regressive manner rather than a«livancing continuously. As the seas began to withdraw in the Late Cretaceous (Campanian), fluctuations again occurred causing short term lvandward transgressions. These east-west pulses formed many relatively thin sedimentary units most of which thicken in a general westward direction toward the source of the sediment, the Sevier Orogenic Belt (Armstrong,l968). The Blackhawk Formation is a portion of one of the later regressive pulses. These wedges are composed of sandstones at the ancient shoreline and grade seaward into near-shore marine mudstones and/or offshore bars. Behind the beach deposits, swamps and marshes formed, many of which were cut intermittently by fluvial channels of delta distributaries and, in some instances, tidal inlets. Further landward, broad floodplains existed and extended to the western mountainous area formed by the Sevier Orogenic Belt. v' p ntI-v-U gown. eve-I ‘ ' The entire region as it has been uplifted and eroded into the resulting escarpments shows excellent onshore and offshore sedimentary features in the long-continuous outcrops. Studies by Spieker (1949b), Young (1955, 1957, 1966), Hale and Van de Graaff (1964), Howard (1966a, 1966b), Hale (1972), Van de Graaff (1972), and Balsley (J. K. Balsley, personal comunication, 1975) interpret the sedimentary features of the Wasatch Plateau and Book Cliffs to be part of several deltaic sequences which include fluvial floodplain, lagoonal, littoral marine, near-shore marine, and offshore marine environments. Maberry (1971) (icescribes openshelf, prodelta-slope, delta-platform, riveramouth bar, beach swamp-marsh-lagoon, estuary, and floodplain deposition at ESlannyside in the Book Cliffs. The present study provides evidence for the existence of floodplain swamp, bottomland and fluvial channel deposition in the middle and southern portions of the Blackhawk Formation in the Wasatch Plateau. coo THE BLACKHAWK FORMATION Sedimentation and Stratigraphy The Blackhawk Formation in the Wasatch Plateau and Book Cliffs is one of the middle formations of the Mesaverde Group. As Maberry (1971) points out, the "Mesaverde Group" in Utah and Wyoming has been the subject of controversy because of the difference in age between these sections and the type section at Mesa Verde National Park in southwestern Colorado. However, he emphasizes that since the term "group" has no time significance, the "Mesaverde Group" designation is appropriate. The term Blackhawk Formation was originally applied to the coal bearing rocks in the Wasatch Plateau by Spieker and Reeside (1925). The type section is at the Blackhawk Mine (now King Mine No. 2), west of Mohrland, Emery County, Utah. Clark (1928) extended the application of the name to the comparable sequence in the Book Cliffs. In an exposure on the west side of the Wasatch Plateau five miles east of Mount Pleasant, the Blackhawk is reported to be 1,700 feet (518 m) in thickness (Pashley, 1956; Doelling, 1972). At the east edge of the plateau, it is about 1,100 feet (335 m) thick (Young, 1966; personal field notes with A. T. Cross, 1970) and thins eastward, intertonguing with the Mancos Shale. For example, at Sunnyside, Utah, 35 miles (56 km) east of Huntington, the formation is 700 feet (213 m) thick and has an 80-100 foot (24-30 m) thick wedge of Mancos Shale in the lower portion (Maberry, 1971). The Blackhawk disappears eastward as a littoral marine sandstone near Thompson, Utah, about 80 miles (135 km) 10 11 east from where it was more than 1000 feet (335 m)thick. Spieker and Reeside (1925) placed the lower boundary of the Blackhawk at the base of the lowest coal exposed in the Wasatch Plateau but later Young (1955) redefined the lowest boundary to include the upper sandstone of the Star Point Formation, the Spring Canyon Member. This sandstone is well defined along the eastern scarp of the Wasatch Plateau. The upper boun- dary was defined (Spieker and Reeside, 1925) as the unconformable base of the Castlegate Sandstone member of the Price River Formation, and in many sections can easily be identified; however, at Water Hollow Road in Salina Canyon, Bachman (1958) found no clear evidence of truncation of the Blackhawk and stated that it appears to be conformable. From my own examination of the Castlegate-Blackhawk contact at the Pipe Springs locality in Salina Canyon, I also agree that they are conformable. In the 1000+ foot (300 m) sequence above the Oliphant mine (abandoned) in Straight Canyon several minor unconformities exist which make it diffi- cult to locate an exact upper boundary. In addition, fine grained sandstones, carbonaceous shales and thin coals, which appear to be lithologically comparable to those in the Blackhawk, exist above some of the unconformities while coarse-grained sandstones comparable to the fluvial sands in the lower Castlegate are found below the unconformities, making the exact boundary very difficult to identify (A. T. Cross, personal communication, 1970). No major unconformity exists at this locality, either. Spieker (1946) suggests that the Castlegate sandstone was deposited upon the slightly eroded surface of the uppermost Blackhawk. He theorizes that the uniformity of this contact in the Wasatch Plateau and the Book Cliffs indicates the lack 12 of extensive erosion of the Blackhawk. Yet because of the marked change of facies between the sediments of the Blackhawk and the Castlegate, a major thrust or a renewed uplift must have occurred in the Sevier Orogenic Belt to rejuvenate the streams draining eastward. Lithologic Character The Blackhawk Formation in the Wasatch Plateau consists mostly of fine to medium-grained sandstone, which varies in color from dark brown on weathered surfaces to buff and gray. These sandstones are composed primarily of somewhat rounded quartz grains, and in many parts appear to be slightly ferruginous. They are usually massive, and commonly show cross-bedding and small lenticular channel deposits out within them (Bachman, 1958; Howard, 1966; Maberry, 1971; and personal observation). The siltstones here are light colored and contain considerable amounts of clay and organic detritus. The claystones and shales are mostly medium to dark gray in color, some being very carbonaceous. At certain horizons, there are thin layers and lenses of coal, varying from a few feet (meters) to less than one-fourth inch (.6 cm) in thickness. These fine-grained sediments (siltstone, claystone and shale) comprise about two-fifths of the sediment in the southwest area of the Wasatch Plateau, and fluvial sandstones, chiefly of point bar origin, comprise the remainder (Bachman, 1958). The fluvio-deltaic sandstone facies changes eastward where, at Sunnyside, most of the thick sandstones were deposited in a littoral marine environment (Maberry, 1971). -~. I. 9.. s“ ‘ ‘. v ‘. \; '~ A I I . . ._.\ \ . ‘s “. V ‘ . . .V g. 13 The thinner coal beds of the Wasatch Plateau vary considerably in thickness, locally, due to a combination of local depositional factors and perhaps to differential compaction. Bachman (1958) notes that the coals generally become slightly thinner very near the outcrop, possibly because they have been pressed out. Cross (A. T. Cross, personal communication, 1975) suggested that they may have lost volume during near—surface oxidation. However, there are other possible explanations. The thicker, minable coals are restricted to the lower third of the formation in the Wasatch Plateau, and are more regional in extent. The Hiawatha coal, for example, is traceable the length of the Wasatch Plateau above the Spring Canyon Member, from at least the Gordon Creek area to 5 miles (8 km) south of the Ivie area of Salina Canyon, a distance of 67 miles (108 km) (Spieker, 1931). The Castlegate coal, above the Hiawatha coal, is visible on the outcrop almost continuously from north of the Gordon Creek area to the Star Point area on the Wasatch Plateau, a distance of 10 miles (16 km), and then for about 40 miles (64 km) northward and eastward along the Book Cliffs. The Blackhawk Formation in the Book Cliffs has been divided into six members, each of which is made up of a basal littoral marine sand- stone and a sequence of coal-bearing rocks above (Young, 1955, 1966) (see Figure 3). Young (1955) mentions that these members are not all present throughout the area because they have been identified only where the basal littoral sandstones are developed. For example, only three of them are present in the section at Sunnyside, Utah (Maberry, 1971). The Spring Canyon Member is the only one of the six which can easily be recog- nized in the sections studied in the Wasatch Plateau area. Above the Spring ‘ 22:! \ i I 9. ..§ 0.4- 14 .303 £53 nuts sous mmmaau soon spouses» or”. we 95.32599. voumaou pom swam—Eucam ecu mo .3333”.me .m 9.3me “H“ s.§...:.:§_3 .53: muzi 0' On ON 0. O 0.2.52 2.20.24 Eva—on I 3:303 EoEuooE use 2.1.253 522.3: Essa-E mw_o€3en prepared under the auspices of the Rocky Mountain Association of (3‘3ologists (McGookey, 1972). It includes a comprehensive overview of t:11e transgressions and regressions of the Western Interior Seaway and 1:1‘3w information on the tectonic activity, sedimentation and stratigraphy of the Lower and Upper Cretaceous system in the form of several paleo- ‘alavironmental maps, restored sections, charts and fence diagrams. The most important geological papers which have had direct bearing uDon this study are Spieker and Baker's (1928) report on the Salina (3anyon coals, Spieker's (1931) work on the correlation of the coals of the Wasatch Plateau, Baughman's (1958) and Bachman's (1958) geologic c an . (II '1- “. I ‘ v ., A I I II \ I s o u I.‘ 20 maps in Salina Canyon, and field guide road logs by Spieker (1949a); Rigby _e_£_a_1 (1966); Rigby gig (1974); and Cross 353.1 (1975). C oal ’ In the region of study,.coa1 has been mined in several major coal fields. In the Wasatch Plateau, these coal fields are the Mt. Pleasant, east of Mt. Pleasant; the Sterling, east of Gunnison; the Salina Canyon, in Salina Canyon; and the Wasatch Plateau, along the eastern escarpment of the Plateau from Spring Canyon to Salina Canyon. Only the Wasatch Plateau coal field is nowactive. West of the study area in the Gunnison Plateau is the abandoned Wales coal field, west of the city Of Moroni. Northeastward, is the Book Cliffs coal field located along the escarpment from Spring Canyon to the Green River. It is the most important in the state with respect to past and present production (Doelling, 1972). The Emery coal field, with two mines in the Ferron cQal (the I-seam of Lupton, 1916), currently active, is located 8<>utheast of Emery. The coal-bearing formations in the active coal fields are the Blackhawk Formation and Ferron Sandstone. Minor coals, some of which hQ-Ve previously been mined are in the Dakota Sandstone, the Six Mile Formation, the Emery Sandstone, the South Flat Formation, the Price R1\rer Formation, and the North Horn Formation. The basis for comprehensive regional coal geology studies in the Bleekhawk and Castlegate was Spieker's detailed mapping of the Salina CaIriyon and Wasatch Plateau coal fields (Spieker and Baker, 1928; SDicker, 1931). In these studies, nearly 600 coal-bearing 21 stratigraphic sections were measured and correlated. Subsequently, numerous reports have been published, the most recent being Maberry's (1971) work on stratigraphy and paleoecology of the lower Blackhawk Formation and Doelling's important monograph (1972) of the central Utah coals. This monograph includes much of Spieker's earlier mapping, plus historical, stratigraphic, engineering, and economic information. Recently, Stewart (1975) has reported renewed exploration and research in areas of the Wasatch Plateau where coal is expected to be mined in the next ten years. Three major symposia have been specifically concerned with the coals of east central Utah. They were, one meeting of the Intermountain Association of Geologists in 1956, and two meetings of the Coal Geology D1Vision, Geological Society of America in 1966 and 1975. Individual 8tudies published in conjunction with these symposia have dealt with I’egional stratigraphy, paleobotany and paleoecology, and coal Petrology, engineering, and palynology (Peterson, 1956; Hamblin and R1gby, 1966; Cross and Maxfield, 1975; Cross, Maxfield, Cotter and C“Poss, 1975) . \Paleobotany The existence of Upper Cretaceous fossil plants in the region has b§en known for many years. Stanton (1894) was the first to collect £03311 plants from the state when examining local stratigraphy near COelville, probably in the Coalville Member of the Frontier Sandstone (Turonian). This collection was subsequently described by Knowlton (1900) and included 10 species. Earlier, Lesquereux (1874), who ll. -’ L. II as. I . In a ,- 50-0. 1 . - -.o a '0..- Ion o we: . ~Il‘ I,_ “It. s: '-o. II I.- s ‘1 I Il- .' . k "v . 22 Clescribed fossil plants from many.localities in the Western Territories, ezzamined invertebrate fossils from the Stranton locality at Coalville, but unfortunately plant fossils were not in that collection. In rocks related to the Blackhawk Formation, several coal ggeaologists and stratigraphers have observed the occurrence of fossil plants. These include: Richardson (1909) who collected gymnosperm and angiosperm leaves from the Book Cliffs mine of western Colorado (Mesa Verde Group?) and from Ballards mine near Thompson, Utah (Farrer Formation?); Lee (1912) who described several ferns, gymnosperms, and angiosperms from near Grand Mesa, Colorado (Paonia Shale?); Thiessen Elrld Sprunk (1937) who identified conifer remains in coal from Sunnyside, Utah (Blackhawk Formation); Hunt (1954) who collected several dicotyledon leaves in the Gunnison Plateau (South Flat Formation); Fisher _e_t_ a_l (1960) who collected several species near Cisco, Utah (Farrer Formation); and Maberry (1971) who collected palms and other Plants from Sunnyside, Utah (Blackhawk Formation). Mention has been made of fossil plants in Salina Canyon by Spieker and Baker (1928), Baughman (1958), Bachman (1958), and Rigby gal (1974). Parker (1968) described 20 species from two localities in that QQuyon. In addition, several large pieces of petrified wood have been Qt>llected near the top of the Blackhawk Formation in Tommy Hollow, in the Ivie Creek area of Salina Canyon (W. D. Tidwell, personal Q‘<>lnmunication, 1970). Preliminary examination indicates that they are EYmnospermous. A large collection of ferns, gymnosperms, and angiosperms was made in Straight'Canyon and Price River Canyon by Cross and Singh n I a‘ I' D I. u- . o.- l --..- I‘.‘ u...- . o A .v .- .‘za: ". n v‘ I u“ - I'm .- , _ \ ‘w 23 (A. T. Cross and H. P. Singh, personal communication, 1970) and later by Cross and others at several additional localities in proximity to Hiawatha, Kenilworth, Castlegate, Price River and North Horn coals (A. T. Cross, personal communication, 1975). £81111010fl Plant microfossils, including algae, spores, and pollen, have received considerable attention as they have related to problems of various sedimentary environments which were associated with the transgressive-regressive Upper Cretaceous sea. These palynological examinations are numerous, but of particular importance are Upshaw . (1962), Lemons (1968), Lohrengel (1969), Orlansky (1970), Thompson (1970), Kidson (1971), Stone (1971), Gies (1972), May (1972a), and Martinez-Hernandez (in preparation) . Palynological studies of the Blackhawk Formation have thus far all been directed toward the coals. These include Wheelwright (1958), May (1972b), and Cross and Singh (1976). %ional Paleoecology Numerous studies of regional Upper Cretaceous paleoecology have reQently been published. Generally, emphasis has been directed toward b"~‘ackish paludal, lagoonal and deltaic environments, and marine beach, barrier bar, and offshore environments. None of these reports have interpreted to any extent the terrestrial environments such as those of the Blackhawk floodplain. However, these studies are important in an overall knowledge of the fluctuating shoreline environments of “an” o oovvvfi w"' o u'nev I ‘ nag-4- no .... O - ' out-0‘ "h.. I '0...- u I! fie. a a I e... u .. -. '- e... ’ 24 deposition and their contemporaneous relationship to terrestrial environments. All of the palynological reports mentioned above have discussed and often emphasized various aspects of local marine paleoecology. In other studies, features such as sedimentary structures, animal fossils and animal trace fossils have been used as paleoenvironmental indicators. Selected important papers include: Zapp and Cobban (1960), Reeside (1957), Sarmiento (1957), Toots (1961, 1962), Tschudy (1961), Hoyt and Weimer (1965), Gray fia_l (1966), Howard (1966a, 1966b, 1966c), Masters (1966, 1967), Young (1966), Maberry (1968, 1971), and Lawyer (1972). 1». . O‘- .-... "I- .v... "n.‘ 0“: q I ? t 'e t ' _ . u,“.: ‘ a ‘L t_ . a. l . e“ . ‘u n . . a ‘u "; 5‘- COLLECTIONS AND METHODS OF STUDY The first two localities which were sampled are in Salina Canyon. fIThese were shown to me by James A. Jensen in September, 1966, in the company of'J. Keith Rigby, W. D. Tidwell, and Alan T. Washburn. These localities were visited several times and, subsequently, other c:<fllecting sites were found, some of which yielded excellent fossil leaves. The entire summer of 1970 was spent in the field, for the purpose‘of making a large collection, gathering pertinent field data taxmd correlating collection sites. Much of this work consisted of Il£>cating additional collecting sites which seemed to have the potential <31? yielding adequate numbers of well-preserved leaf specimens and which werer‘easonably accessible to roads. Outcrops examined were principally 3111 Huntington, Straight, Ferron, Ivie and Salina Canyons. It was my thlitial intention to gather the first 500 specimens of any sort, in c>ltder to give statistical validity to analyses in the laboratory. This plan was soon abandoned as being generally impractical. Multiple fossil I’JLant levels at each locality were also sought. The locations of the six principal localities finally selected and 8tudied in this report are given in Appendix I. Qlections The correlation of the sites within the six major collection localities is shown in Figure 4, where the relationship of these sites to the overlying and underlying formations is indicated. The 25 26 .H muawwm ma woumowvaa moHuHHmooH ecu . um mouum aowuomaaoo osu mo :oaumamuuoo owaemuwaumuum a ouswfim 32:33 3.23:3 6:0: :52; an: «5: 05: Beam use!) on: .31: 233. 2.953 Joe; .39 o] c banuc‘ 5:3 3:3 u ~c~\m~\m ASSMEM lluo~\- ~Om\ ux : Zenxmw\m Saxon; :om\o~\m Henxowxw u u { ¢u_1—.ao.._ .coa u v3.26 Verna a... ( (A L CHQUCJOZ C303 5H0 :otna: ye aunt...» dengue...“ u ~_cx\mN\n suntan 3:2 20:22 :_otwmm\\h u u :9: a 3 2.3. 3:00 u emote“: a u . .822: [CS o. . 22;: a .Tm : . :91 c :5 81:...“ :omflt 82:: u mm “x \ «wok.» a u 1.23!» Amt?” \\ :chESm u .Iuo~\n~\m Zeta: ~ :2: 5&2» xgmzxum_m “x naca nxqfixm I! uucz cmxm~xm ~\«~\m 36ml. “:2; [:5 i... :23 #30 .lé u 5:0 aunts—boo { O>OA< « VQOK page m-:_I 106‘ q lands— ncunl a. oust—3m «3.3-0.5 u u glean 8n: accuntcum 332:5 27 unconformity between the Blackhawk Formation and the Castlegate Sandstone at the Cox Swale locality has been observed (A. T. Cross, personal comunication, 1970) and presumably exists at the Black Diamond Mine also. No major unconformities exist at the Taylor Flat car Pipe Spring localities (personal observation). The entire Blackhawk Formation, where it was measured in Straight Canyon, was about 1000 feet (300 m) thick. As collections were being made at specific levels, care was taken to combine as a single unit or "florule" only those fossils which seemed to have been buried contemporaneously in the sediment. These predominantly thanatocoenosic assemblages of leaves reflect the local commities more accurately than do the pollen-spore floras. They are Composed of plants which lived in a specific type of community which was in and imediately near the local basin of deposition, since Chaney (1924, 1925) has shown that leaves of living trees found buried Within modern sedimentary traps have not traveled far from the parent Plant after being shed. Because of several factors, all species of a living community are nOt preserved in nearby sedimentary traps. Therefore, the composition of the ancient community is admittedly only partially represented. In no cases were the collections grouped from stratified zones tllicker than 10 inches (25 cm). Usually they were much thinner, 1- e., 4 to 8 inches (10 to 20 cm). This practice, although very 8imple in its concept, is used only occasionally in studying major Q<>llections of fossil plants. Many studies have been made in which all the specimens collected at various levels or zones have been r 3 S . 0-. peso-y: '5"- "bsn‘ l l (a . . §~‘ ... 'c ' . a o a ' . . . k“ ‘ I. . ‘~ ‘1 . ‘. a an. . I. I . ~ I K a £3“ . b N I “v‘ . _. .1 x: .. -C 9'. 0-. ‘l‘ A . 28 combined into units and termed "floras" even though it is obvious that such stratigraphically and areally disjunct collections do not represent the equivalent of a living flora. Considerable spans of time and often a somewhat different sedimentary environment may have separated the collection sites. For example, if collections of the Blackhawk Forma- tion were combined, there would be several hundred feet (meters) of coastal fluvial clastics between the uppermost and lowermost, repre- senting a span of time of about 2 to 4 million years. In addition, many paleobotanical studies have ignored the environmental and often even the evolutionary changes which may have occurred during the time the "flora" existed. A noteworthy exception is the report on the vegetation and paleoecology of the upper Miocene Sucker Creek Flora (Taggart & Cross,l974). In a few instances in this study, unusual or especially good isolated specimens found on float blocks were also collected, but kept separate from the individual florules. It is unfortunate that modern ecological methods have been applied so infrequently to paleobotanical studies. Chaney established a firm base for realistic paleoecological plant studies fifty years ago with his qualitative studies of the Miocene Bridge Creek flora (Chaney, 1924), and when he compared that flora with a modern redwood forest of California (Chaney, 1925). Although conclusions drawn from such studies may be controversial, the value of accumulation and interpretation of such data is indisputable. In this regard, paleozoologists and geologists have produced several important studies on what are obviously the remains of true biotic communities (e.g., Zangerl and Richardson, 1963; Beer, 1969). 29 Field Methods Notes and sketches in the field were amplified with many surface and aerial photographs which were of some help in determining stratigraphic correlation of the collection sites. Several beds were followed by continuous tracing on the outcrop to verify correlations. Thicknesses of rock units were made by direct measurement or with a Brunton compass. The largest blocks that could be handled were removed from the outcrop in order to obtain the most complete specimens. All fossils were individually wrapped in newspaper and given the specific site identification number. The rock types (matrix in which the fossils were preserved) of each collecting locality were examined for sedimentary features which might be significant, but grain size and organic content were particularly noted and recorded. Grain size measured in the field was very subjective but sandstones, siltstones, and claystones were distinguished. Determination of organic content was also subjective, based on the color of the rock; dark colors usually indicating a higher organic content than lighter colors. Curatorial Procedures The fossils have been placed in drawer-type museum cabinets in the Geology Storage area at Michigan State University. Curating the collections was accomplished with a system of numbers and letters which identify the collecting site, the particular block or rock, and the individual plant specimen. An example is the following: 8/24/70 001-002 ‘u 30 where "8/24/70" is the date the plants were collected and corresponds to field notes as being a specific collection site, since no other collections were-made on that date. "001" is the number of the rock block which contains the fossil plants (one to several specimens may be on one block); "002" is the specimen number, indicating that it is the second specimen to be numbered on that block. If both halves (or several pieces) of a single block were present, they both received the same series of numbers, but they were individually designated by giving each portion a different letter at the end of the block number. In the case of specimens on these blocks which were represented by part and counter—part (obverse and reverse), each one of these was also given a different letter designation at the end of their number. Thus, the following example: 8/24/70 and 8/24/70 001A-002A 001B-002B where the numbers represent both parts of a single block which contained part and counter-part of specimen number 002. Both blocks and specimens were numbered consecutively; thus, the second block would be 002 and if two specimens were present they would be numbered 002-003 and 002-004 (001-001 and 001-002 were on the first block). This system proved very useful in retrieving a particular specimen from its florule or separating and refiling several specimens after various types of taxonomic combinations had been made (e. 3., after several specimens of Sequoia cuneata from different florules had been combined for comparative purposes). 31 Photqgraphic Catalog A catalog containing more than 2100 life-size photographs was assembled to facilitate study of the fossil plants by photographing and making life-sized prints of the specimens. In addition to the fossil specimens, a mm scale and the collection number were positioned so as to be within the limits of the photograph. The prints were attached to one corner of 8 x 10-1/2 inch punch cards with dry-mounting tissue. It was thought that a punch card retrieval system would be useful in identifying the specimens, but this aspect of the catalog has not been developed. Cards with.simi1ar-appearing types of plants were placed together in groups. Names and references useful for identifying the fossil plants, and other data are recorded on the punch cards. LaboratorygTechniques Laboratory studies of the fossil plants included the following: Cuticle preparation and study. -- The cuticle of fossil plants is often sufficiently characteristic to be of value in identification. Severa1.fragmentary pieces of cuticle were removed from some specimens using techniques of Dilcher (1963, and D. L. Dilcher, personal communication, 1973). However, only a small percentage of the leaves yielded good cuticular preparations. Although there is often a considerable amount of dark, flakey, carbonaceous substance present including what appears to be the cuticle, it does not have the impressions of epidermal cells and stoma in it. About one out of thirty leaves examined for cuticle produced results. oIIO‘. . , ..q-ua .a 0.». I III... ..‘-I .0... -.‘. 32 In additional attempts to observe epidermal cell patterns or stomatal bands on gymnospermous leaves, a scanning electron microscope (SEM) was used. Items examined included carbonaceous leaf remains (bleached and unbleached), rubber latex and polyvinyl chloride casts of leaf impressions, and several small pieces of the actual fossil leaf impression in the rock matrix. All of the above materials were mounted on small coverglasses with double-edged tape in standard mounting procedures, coated, and examined (Taylor, 1968). Although J. W. Schopf has obtained SEM photographs of epidermal cells of Chlamites sp. impressions (A. T. Cross, personal communication, 1972), no such cell patterns or stomatal bands could be observed on the Black- hawk specimens which were examined. Palynological examinations. -- Several specimens of what appeared to be male gymnosperm cones, catkin-like structures and marginal sporangia of a fern were chipped from the rock matrix (often the complete specimen was used after it was photographed, while at other times only a portion of the specimen was removed) and macerated with standard palynological techniques (Cross, 1968) to remove the rock matrix and isolate whatever pollen or spores might be present. This was successful with some of the specimens, producing excellent slides of palynomorphs, which in one case facilitated identification of a ‘megafossil fern (SaccoZoma gardneri). Rock matrix and coal from several different collection sites was macerated, and microscope slides were made of the palynomorphs which were isolated. The slides were examined, but no results are included in this study. 33 'Mggascopic leaf preparations - excavation. -— Often it was necessary to uncover or excavate partially buried leaf compressions, stems, and reproductive structures. This was successfully accomplished using small chisels with a.narrow cutting edge (1/16 to 3/16 inches width). Dissecting needles or dental tools proved ineffective. This technique was valuable to this study and resulted in many complete and nearly complete angiosperm leaves and leafy conifer twigs. More importantly, several physical connections between certain structures were determined. 'Some of these had not been reported before and include: the marginal sporangia (with spores) of Sdccoloma gardheri; the attachment of sequoia cuneata foliage to cones; the attachment of ProtophyZZocZadus polymorpha phyllodes to a branching axis; the attachment of a Mbriconia cyclotoxon branch to a branching axis; and the connection of several elongate lobes to one large leaf of Mbnihotites georgiana. Identification of the Specimens Initial identification of the Blackhawk plants was accomplished by comparing photographs of the fossils with illustrations in the literature. The "Catalogue of Mesozoic and Cenozoic Plants of North America" at Princeton University (Dorf, 1940) was used extensively and was a major aid in determining those plants which had been illustrated and previously described. This method has been justifiably criticized by Dilcher (1974), but.at this time no better way is known. In addition, herbarium specimens and living plants were used in order to compare venation patterns, epidermal cell patterns, glandular u. .. unite 1:: II I . I ‘00. a 9...... l"... ' I 34 structures, cone structures, and gymnosperm branching and leaf structures. When possible, the cuticle of fossil specimens was removed from the rock matrix, cleared, then examined microscopically as an aid to determine identity. As a result, certain of the fossil plants, notably a few of the ferns, some of the gymnosperms, and a few of the angiosperms, can be reliably correlated with living plant groups, often at the generic level. THE BLACKHAWK PLANTS AND FLORISTIC RELATIONSHIPS Plants in the Blackhawk Formation A total of 118 species have been collected and described in this study including leaf and twig compressions, a portion of a lignified gymnosperm log, and casts of several fruit or seed-like structures. In addition, many interesting in gigg plant roots and stems were seen in the field, but these were not studied. The collection studied includes nearly 7,500 specimens, about oneéhalf of which are well-preserved enough to be identified or characterized. .The unidentified specimens are usually too poorly preserved or fragmented to be useful, but apparently they all are dicotyledon leaves. Of the plants which could be characterized, there is one thalloid,.1iverwort-like plant, one club moss-like specimen, fourteen ferns, twelve gymnosperms of various types, and eighty—six angiosperms. Angiosperms are represented by five monocotyledons and eighty-one dicotyledons (see Table 1). Although all the gymnosperms and monocotyledons have been previously identified, only six of the ferns and fifty dicotyledons appear to have been previously described. The eight unidentified ferns and thirty-one unidentified dicotyledons are thought to be previously undescribed species. This large number of new species, roughly one-fourth of the total in the collection, seems very large, but might be justified in two ways. First, the continental flora of the Cretaceous 35 36 MN N H wmwrmrwwondo ExHmeQonmnmonb o H N H n a «H H Exmwrumwm EsNmeuormbeux oH OH 0 Ezmooumnb Loom meanest Nerorx N N HacoaHooee HNoNV acovonuouHo H excuses omnwwoaom H m3.eoesu ewuaHQ omen ml 3 m a n H .c s a o m N : . ~ .V a N . .. e. . n a «N a ammnmte V» maumrmrumu c H o N N H .en enamoonwumb m ov.ohmrmet scrub HecosHoueu oov ecouonuooocox msaommonc< H H NH NH HuuchHHv v00: auweeocexu cow 0 H o . 32?.»me wwuwrfiucrwkmfiupk On Q H O N O m HM nu 00 Ma 0 no» we N H .— H N H O m NON mH «eunuorlfi UwQSWQW cc .an a .o.ooa m:eo-oc «2 H o n H. N S I L .. . . a omH N H “NH NH m M NH «H M M H H N NH N m N dxmnoemmon msHoHooNManzuexm .an no.2Lonm a NNoH .. 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I I I ”am an murmur muzummz mmm nxprpp m m m n a a n m. w u m a a W m u Hu.=oov .H «Hana 39 Santonian-Campanian Stages is not as well known (due to fewer collections in rocks of that age) as those of other stages (e.g., the Western Interior flora of the Maestrichtian stage or the Dakota flora of the Albian and Cenomanian stages), and second, it is probable that most floras represent unique communities since they are normally isolated geographically and through time from other floras. Although some of the new species found in this flora may subsequently be found in others, the Blackhawk flora should generally remain a distinctive unit. By way of interest, the Lance Creek and Medicine Bow floras (Dorf, 1942) of the well-collected Maestrichtian Stage each also have roughly one-fourth of the species described as new. Other Cretaceous and Tertiary floras have many more (e.g.,Hollick's study in Alaska, 1930, 1936). Relationships to Other Floras The rocks of every florule were carefully examined and the numbers of specimens of each species were recorded. Table 1 lists all the species recognized in the Blackhawk flora and was used in several paleobotanical analyses which will be described and discussed subsequently. In order to compare the ages of selected Cretaceous fossil leaf floras in North America, a time correlation chart, Figure 5, was compiled from the literature. It illustrates the approximate age of the fossiliferous zones of each flora and the number of species collected. References to these floras and to the stratigraphy is 40 C I E T A C E O U S P . R 1 0 D z o n E References : g H n g. n 2 Name of Number References to Relative g > > o E a 3 E K heclugic Unit of Species to Flora Stratigraphic i ‘3. ’5’ E S 2 3 S 7? ”sum" '3 'u‘ 3‘ S“ i? a“ 5‘ K F.“ :1 :3 :3 :1 :3 3 :2 :1 :a _ i'atun'nt Fm. 8’" Berry, 1911a Dorf, 1952 Blairmore Pm.(lowcr; 28 Berry, 1929b McGookey. 1972 Potomac Group 541 Fontaine, 1889, Dori. 1952 1905b Arundel Fm. 38 Berry, 19118 McGookey. 1972 4 Blaimore Fm.(upper) 18 Berry. 1929C "Above the Morrison Cockerell, 1916 ? hquivalent" P itootcnay Series 90 Knowlton, 1907; HCCOORQY. 1972 brown, 1946: Berry, 1929 _ iiomc Beds 8" Seward, 1926 : ilootenay Series 63: Neuberry. 1891; McGookey. 1972 Fontaine, 1892, 19053.1907 -, hurrn Canvon 19 Brown, 1950 McGookey. 1972 brntun Shale of 96 Ward, 1899 Dakota 35. .. Trinity Group 23 Fontaine. 1893 Stepheson. 1942 — l'nlnpscn Fm. 75 Berry. 1911a Dori', 1952 _ kaltng, Nulato 6 211 Hollick, 1930 Inlay, 1954 Helozl Pas. .‘Junusnuk Group Smiley, 1969 lmlay, 1956 _ (‘m-vcnne .95. 23 Berry. 1922 Cobban g_t_ LI'SZ fink River Deposits Smiley. 1966 Smiley. 1966 _ Aspen Shale 1!. Brown. 1933 McGookey, 1972 Frontier ha. 34 Knowlton, 1917a; McGookey. 1972 Berry. 19303 _ Dakota Group 1.60 Lesquereux, 1892 Cobban gt 3.1.52 _ Dakota Pin. 32 Lesquereux, 1895 Cobban _e_t 9152 Berry, 1939 _. Illniw-gan Fm. 66 Bell, 1963 Scott. 1963 _ Woodbine Sand 53 Berry, 1922b Stephenson.19&2 __ 'iuwnloosa Fm 151 Berry, 1919 StephensonJ942 (with 3 minor (ms) _________ Roritan Fm. 6 256 Hollick, 1906; Dorf. 1952 Clifiwood Fm. Holllck 6 Jeffery, 1909 Paritnn Fm. 170 Bvrry. 1911b Dorf, 1952 _—_ Hirimn Fm. 21) Berry. 1916b Dori. 1932 ‘L_. Raritan Fm. 25 Berrv,l905b.l916 Dorf, 1°52 inlville Group Smiley, 1969 lmlay, 1956 _ hriran Fm. 156 Nuwberry, 1895 Dori, 1952: (Amhoy Clays) Uilmdrth,1913 __ i‘runricr Fm. 8 Andrews 6 McGookey, 1972 Pearshall, 1941 ‘10.“.1Vt‘l'd9 Group 2 Brown, 1956 Cobban _e_t 21'52 __’ “Inck (reek Fm. 76 Berry, 1916 Dori, 1952 (Hiddendorf Arkos) h__+, (hignik Fm. 72 Hollick, 1930 Imlay, 1954 ,_ Lutaw fin. "3 Berry, 1919 Stephenson.19~"2 1 (with 3 others) #- imau Fm. 27 Berry. 1914 StephensonJ‘MZ 1.. Bodheart Fin. 6 Bell, 1963 Scott, 1963 __._ ”rincc Creek Fm. Smiley, 1969 lmlay, 1956 (luluvak Tongue) _‘_. Vunuthy Fm. 56 Berry, 1906 Miller, 1974 _‘__ Wagothy Fm. 100: Berry, 1908, Miller, 1974 1916; Penny, 1947 Jtauan Fm. 105 Berry, 1903a, Dorf. 1952 19036.1904,1916 Milk River Fm. 28 Bell, 1963 Seott, 1963 ‘.___ Blackhawk Fm. 118 This Study McGookey. 1972 L Allison Fm. (lower) 10 Berry, 1929:: Scott, 1963 (- Belly River Fm) Montana "Fm." 91 Knowlton, 1900 McGookey, 1972 ____ Prinve Creek Fm. 1 Arnold G Lowther, Inlay, 1954 (Kogosukurk Tongue) 1955 _ 01d Hnn Shale Ramanujam 6 McGookey, 1972 Hilson, 1969b __ Edmonton Fin. 4 Ramanujam 5 Uilmarth, 1938; 1— Hilson, 1969a McGookey. 19721 __ Fruitlnnd Fm. A 60 Knowlton, 1916 McGookey. 1972 Kirtlsnd Fm. Laramie Fm. 131 Knowlton, 1922 McGookey, 1972 — Riph-v Fm. 6 Berry, 1914 Stephenson.1992 _ kipicy Fm. 135 Berry, 1919,1925 StephensonJ‘MZ _, Fox Hills Fm. 61o Dorf, 1938 McGookey. 1972 .-_-q Hell Creek Fm. 19 Brown, 1939 McGookey, 1972 (Colgate Member) _, lJncc Fm. 10 Berry. 1936 McGookey, 1972 - '.-l|1(\’ 1.1‘1. 70 Dorf, 19142 HCCOOKEV, 1972 - \‘n r'wjn Fm. 108 Knowlton, 1917b Cobban gt a_1'52 _ "Laramie Group" 112 Lesquereux, 1888 McGookey, 1972 __i lnramiv Fm. 131 Knowlton, 1922 McGookey, 1972 _}Dvnvvr Pm. (and 145 Knowlton, 1930 McGookey, 1972 Uthvr minor fms.) kmir-ns fin. 59 Knowlton. 1921. HcGookev. 1972 Figure 5. The major Cretaceous floras of North.America showing the approximate relative stratigraphic range of the collection localities within the formations, the number of species in each flora and references to the floras and stratigraphy. The Blackhawk study is included. ..-"'o . l n...‘ A r .E’.‘o '\ 41 also indicated. Studies concerned with petrified wood and palynological analyses have generally been omitted. my personal interpretation was used in placing time limits on the fossiliferous zones. If it could be determined that a fossil collection was made in a specific member or portion of the formation involved, only that member was included on the chart. Unfortunately, several authors have neglected to place any significance on the stratigraphic position of their collections and a few have omitted exact geographical localities. It has not been uncommon to group together as the "flora" those specimens collected at localities widely separated both geographically and stratigraphically. These factors have made the stratigraphic determinations difficult and not as accurate as desired. Studies made in a single formation but of widely separated geographic locations have been considered separately on the chart. Total species counts for each report was usually determined by counting those fossil plants discussed, inasmuch as few reports volunteered a total. This is also not as accurate as desired, since several floras have been reworked one or more times with additions, deletions, or combinations with every new study. Therefore, the number of species indicated may be subject to revision. In certain floras, total species have not been determined and thus, are not indicated on Figure 5. In other studies (Smiley, 1966, 1969), floral lists and descriptions are not yet published. It is interesting that one or more major floras have been ckescribed from nearly every Cretaceous epoch. Floras of some epochs I , , u v .I ' I v. owl 0 v6.4. - P y.- ._.. . ' 9‘1 a '60... 1 'q._ u... o .- a O“~ 42 have been studied more extensively but this is generally a reflection of the areal extent and thickness of the rocks of that epoch, and the length of the epoch. At this time the Blackhawk plant species have not been critically compared to those of the other floras to determine common species. This comparison is made particularly difficult by the many name changes over the years. However, there are at least two Lower Cretaceous relict genera which were still in existence in the Blackhawk, Nageiopsis sp. and Podozamites sp., both apparent gymnosperm-like plants. The age relationship of the Blackhawk flora to other Cretaceous floras is shown in Figure 5. Also indicated is the number of Blackhawk species; only about 10 other floras have more species, making the Blackhawk among the largest in North America. PALEOECOLOGY Identification of Blackhawk Fluvial Environments of Deposition The fossil plants in this study were collected in what has been identified as fluvial sediments deposited on the broad floodplain of the Blackhawk River system (Young, 1966; McGookey, 1972), rather than from the lagoonal, paludal or littoral marine environments which were at or near the western edge of the Upper Cretaceous Mancos seaway, described by Young (1966) and Maberry (1971). These floodplain sediments formed most of the upper and western portions of the forma- tion in the wasatch Plateau (Spieker and Baker, 1928; Baughman, 1958; and personal field observations at Water Hollow Road with Edward Cotter, Aureal T. Cross, Timothy Cross, John Horne and Wm. D. Tidwell, October 19, 1975). Two general types of sedimentary environments exist on modern floodplains (Fisk, 1952; Shelford, 1963; Dury, 1970; Wolman and Leopold, 1972). The first is in-channel deposition which forms point bars by lateral accretion within the river channel itself. The second is over- bank deposition which occurs outside the channel during river flood stage on levees, bottomlands and swamps. The aggregate thickness of recent floodplains has been estimated to consist of at least 80% point bar deposition, while overbank flow contributes the rest of the total thickness (Wolman and Leopold, 1957). This is consistent with obser- vations made by Bachman (1958) in the Blackhawk paleofloodplain where Insint bar deposition makes up at least three-fifths of the total 43 44 thickness. Although in-channel deposition is significant in floodplain build-up, it is in overbank sediments that most of the well-preserved Blackhawk fossil plants have been preserved. Specific kinds of depositional environments which are evident in the Blackhawk floodplain are in-channel features such as point bars, and non-channel features such as swamps and bottomlands. The lenticular, resistant sandstone ledges which are abundant in nearly every outcrOp are usually of point bar origin, while the abundant coals and carbon- aceous shales are an indication of the presence of peat-forming swamps. Some of these were formed in abandoned channels but most are on inter- fluve sags or lows. Less obvious are overbank sediments of bottomland origin because of their variable composition and thickness. Levees, which are common along active channels of modern rivers, are not recognized in the Blackhawk floodplain. There seems to be no good explanation for this but they may have been scoured away from shifting river activity or may have settled due to compactation of underlying sediment, particularly if there was a significant amount of organic matter under them. In this case, the levee environment is indistin— guishable from other sedimentary environments of bottomland origin. On some recent floodplains, levees have their own unique plant communities (Gould and Morgan, 1962). It has generally been difficult to distinguish specific types of fluvial deposition from cores or outcrops (Wolman and Le0pold, 1957). However, examinations by Fisk (1947) allowed him to differentiate .Beveral types of environments from shallow Mississippi River flood- Ifilain cores. More recently, Visher (1972) and Schumm (1972) have 45 established several criteria for identifying specific paleofluvial environments. In this study several biological and sedimentary criteria were used to delineate three fluvial depositional environments in Blackhawk floodplain sediments. These are described in Table 2. Organic content, indicated by rock color, and size of mineral particles were the chief criteria used. Blackhawk rocks with a high organic content are usually composed of clay-sized particles. Often a small proportion of silt and fine-grained sand was present. Rocks of this nature are thought to have been deposited in local, swampy basins where an abundance of semi-decomposed plant and animal tissue was present; the clay settled out of nearly motionless water. Other features such as thin bedding, stratigraphic relationship to coals, and types of animal and plant fossils present, also indicated a swamp origin. Point bar sediments are also characteristic, with certain features strongly contrasting to those of swamps. Organic content is very low, indicated by light colored rock. Grain size is coarser, ranging from fine-grained sand to fine pebble gravel. Usually these sediments were well washed, containing little clay. Sedimentary features also suggest Imigher energy deposition and include cross-bedding, ripple marks, thin gravel lenses, and a general lenticular form. Water-worn wood pebbles indicate high energy transportation. Load casts of various kinds can be seen in the field (E. Cotter, A. T. Cross, J. Horne, personal communication, 1975). Bottomland sediments were more difficult to identify, but normally exilibited features which are intermediate between those of swamps and 46 Thble 2. Criteria used for the identification of fluvial environments in the Blackhawk Formation. Environment Sedimentary Features Biological Features Swamps 1. Grain size: sandy silt to clay 1. Small gastropod shells 2. Sedimentary features: shales thin often present. bedding laminae often present; no 2. In situ stumps and roots. current structures such as ripple . Water lily and water marks or cross-bedding. Erodes chestnut fossils have away easily leaving overhanging led f oi t b rs. been collected. ges o p n a II I! 3. Organic content in shales: high, 4' Leaf mats are often dark gray to black in color. Shales present. associated above and below coals 5. Leaf preservation good. of various thicknesses, or as partings in coal, or lateral to coals. FNDint Bars 1. Grain size: silty coarse to fine 1. Casts of water-worn wood grained sand. pebbles and small logs 2. Sedimentary features: massive sand- ifizniagzz: figitzases Of stones, cross-bedding often present; ° gravel lenses in thickest beds. 2. Leaf preservation poor; Ripple marks often evident. Thick- with some transport ness varies from 0.5 meter to about damage. Leaves preserved 12 meters. Very lensy in nature, at angles to horizontal limited from 100 to 200 meters wide, plane. lateral faces intertonguing with siltstones or shales. Forming abundant, local, overhanging ledges. 3. Organic content: very slight, composed of well—washed sands, orange to buff color, never gray. Fresh surfaces are light colored. BOttomlands 1. Grain size: sandy silt to clay. I. Meandering invertebrate 2. Sedimentary features: thin bedded, trains often preserved. often platy; raindrop patterns; never 2. Leaf "mats" are very associated directly with coals of any abundant at every thickness, but may be found 2 to 4 collecting site. meters above or below a coal or dark 3 In situ stumps and roots shale. Rocks often mottled. Usually ' more resistant than swamp deposits, present. but less resistant than point bar 4. Leaf preservation good. deposits. 3. Organic content: medium to low, light gray to yellow in color. 47 point bars. Grain size is usually silt, but varying proportions of clay and fine-grained sand are present. Organic content varies but is usually much less than in rocks of swamp origin. Features such as raindrop casts and invertebrate trails also indicate deposition in a terrestrial, low energy sedimentary environment. Indications in the field are that these environments were local, rather than regional, as might be expected on the floodplain of an actively meandering river. No deltaic or neritic sedimentary features such as delta platforms, salt marshes, tidal channels, intertidal flats, beaches, riverdmouth bars or offshore bars, which have been character- ized by Maberry (1971) and Rigby and Hamblin (1972) could be distinguished. Nineteen of the collection sites were found to be from rocks of swamp origin, 14 were from rocks of bottomland origin and 8 collections were made in point bars. Table 3 indicates the environments of each of these sites. Correlation of the Fossil Plants with Environments of Deposition Because several factors of preservation make it relatively unlikely that all species of a community will be preserved as fossils, the plants which make up the Blackhawk communities are almost certainly dispr0portionately represented in the collections. However, several factors including community structure in each environment can be deduced from the plants which are represented. At the time the fossil collections were being made it became apparent that certain species seemed to be restricted to rocks of a 48 TABLE 3. The type of floodplain environments suggested for each of the fossil collection sites. Collection Number Environment 6/1/68 Swamp 7/9/70 I-l " 7/11/70 II " 7/12/70 " 7/18/70 I-l " 7/18/70 I-2 " 7/28/70 I-2 " 7/28/70 1-5 " 8/13/70 " 8/14/70 " 8/15/70 " 8/18/70 " 8/19/70 " 8/20/70 " 8/24/70 " 8/28/70 I " Unit I " Unit K " Unit M " 7/8/70 I-l Bottomland 7/9/70 I-Z " 7/9/70 I-3 " 7/11/70 I " 7/23/70 I " 7/28/70 II " 7/30/70 I " 7/30/70 11 " 7/30/70 III " 8/25/70 " 8/28/70 II " 8/28/70 III " 8/29/70 " Rail Road Cut " 7/17/70 I-l Point Bar 7/22/70 " 8/26/70 I " 8/26/70 II " 8/26/70 III " Above Rail Road Cut " Base of Road Cut " Road Construction 49 particular lithologic character. A quantitative study to support this observation could not be made in the field, but was attempted in the laboratory after the specimens were curated, photographed and identified. In the combined floras there were 43 species which were represented by 10 or more individual specimens. I arbitrarily considered these species abundant enough to be ecologically significant in the original forests. These 43 most important species are listed in Table 4 where the collection sites have been grouped together into major floodplain environment types. The number of specimens of each species collected ‘within each site is indicated. Figure 6 shows the percentage of each of the 43 species which were found in the three environments. Most of the species indicate a strong preference for a single environment, but a few species seem to overlap from one to another as might be expected in natural commu- nities. Several species were found in only one of the environments. This was the first indication that specific plant communities existed on the Blackhawk floodplain. Therefore an attempt was made to obtain as much quantitative data as possible about the plant assemblages of these environments. Quantitative Paleoecology Chaney (1925) established a sound basis for quantitative paleo— ecological analysis of certain fossil floras when he compared data obtained from a living redwood community with what he believed to be a nearly similar Tertiary flora. He showed that a high number of 50 .conmsomHo no. axon mom .chHa vooHu ecu cmcu nonuou :HmHa muHoo ago no on NHHasuum Noe mouHm coHuuwHHOU omonhc 0 NH NH Nm uouHa caocxca o Hm Hm nN ocan chocxcs wH NH o H H m N o wH ocan caocxc: a H m mm ON 0 NH nooHn csocxc: qu N NoH o N uooHn anocxc: H H cN MN m m H H H Exmmwurn ExFHfimb” NH H N m H H aroorunm HHHHi 0 HH n o N Grimmvdwunku Ramona c o mH NH m mzornzum HmHuw N N m mH m N N m ch H mHmH m NH qH Hm a HH HH H NN mrwrmru ouhmztdxm w H H c N umH H o w mH Nn nH wN NH 0 m a r H Hm H o m c m c mmfiwwrmmL exxuaonu NH oH N H H N snows mxxuaoum mm 3 N HH m m NH H H HH m....:..o......£% .85..me H... on H H H H 2 H H H H o 33.8 viking“... 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HH N x n N H N 3 m N H H o o m N a 936.23.... merges... q a CN 0 m N H .mm emamhugumnu o NH NH mmcommL mwuwrtpmrmzmfimk m H N HN e o N N H H qu H o o o HmmH we NH 0 me me H H a m NonH «avenge H cxnem cm H as N .Am wsflumooanHL.HuLN .H H H H 2 H 2 H N 2., o H 2 m H HH .H H H H H HH w germaneu axHHHHoSH...H.....H,:.._...... wNH wNH 0 HH N H H N .om umuukumzm.k o S 2 .am 3...... is H H on m H m N H NN rouoooHoab umroom wk o mmH H cmH oH q o Exugnoo our Esmmmxumcmdsm .om mmumknoanw H. 2 H 2 HH 2 w H 5.. 2...... mm H HH N HH m a H N H “Homecx morzswd m m OH on commmktux summare Nm Nm ouwrxmm uuxuumb NH NH Exromromxowfi exmrsmhmw wwwmmmunmwNNNNHHHHHNHHHmmmmmo/ommmmmmnnnnuum I O O 7. 7. 7... 7. I l I. 7» 7. 7. .6 C r... to 7. 7. I 6 6 8 I I. T. T. 7.. Z 7. T. T. I T. .I. .6 Z .l I T. T. T. WPMNNNRHWIMNNKNNNNKNUUUwzznmnmmmmnnmmmmnnw wammmmm wammmumumwwooo unlmmmmmmmmmmmmmme SHAH. u . I I I I S u I I I I D. I I I I I T. I I . . _ I T. I I I I 3 . I I . I I I I I t... Z T. I. _ _ _ . I J I I 3 I 0 I C. 7. .6 I m m m s n 1 m gleam magnum mam omosouw mum mouHm coauUOHHou was name No mamafiuuoo no woman: was .musoasowa>sm :Honooon uohma m .nsonu ma usoesouH>su some swnufis «nu ousH wonuowou nouooHHoo muHuoam .ouOHm xasnxomHm onu nH moHooom unmuuomaH owes me use .c anmB 51 Taxa Total Number of specimens 292m Asplenium dicksonianum Cyathea pinnata Onoclea hebridica Bnachyphyllum macrocarpum Mbriconia cyclotoxon Nageiopsis sp. Protophyllocladus polymorpha sequoia cuneata Widdringtonites rsichii Cyperacites sp. Gbonomites imperialis Anona robusta Cissus marginata Cbrnus praeimpressa Ficus planicostata Rhamnites eminens ShZix gardneri Salim proteaefo Zia Unknown dicot 13 Unknown dicot 25 Unknown dicot 32 Osmundh hoZZicki Unknown fern l Protophyllocladus sp. 2 Apocynophyllum giganteum Cbrcidfiphyllum arcticum Cbrnus dbnverensis Dryvphyllum subfhlcatum Dryophyllum whitmani Ficus Zaurophylla Laurophyllum coloradénsis Mbnihotites georgiana Mbnispermum dhuricumoides Myrtophyllum torreyi Phyllites vermejoensis Platanus aZata Platanus raynoldsii Shlix stantoni Viburnum antiguum Unknown dicot 2 Araucarites sp. Pbdbzamites sp. Unknown dicot 19 Swamps (Percent of total specimens) 02 502 1002 Bottomlands (Percent of total specimens) 02 502 100% Point Bars (Percent of total specimens) 02 502 1002 Figure 6. The percentage of total specimens collected of the most important fossil plants in each of the three Blackhawk They are listed in phylogenetic order within each of the environments. floodplain environments. 52 leaves of a particular species in modern fluvial sedimentary environ- ments usually indicate a relatively high proportion of living plants of the same species in the immediate vicinity (with 50 feet or 17 meters). However, no subsequent examinations of fossil floras have used Cheney's ecological work, although numerous significant floras have been written. In this study it is generally assumed that in each collection site, a relatively high number of leaves (or leafy twigs or phyllodes) of a particular species also indicates that the most abundant local trees were of the same species. It is reasonable to believe that leaves of certain fossil plant species which are consistently abundant in a majority of collection sites, were shed by plants which are probably the most abundant in the community. Within each major environment, the number of leaf specimens in each collection site (or florule) was analyzed together with the number from the other sites and is discussed below. This is analogous to the treatment of data obtained from individual "plots" when living plant communities are examined. Several factors are often considered in ecological studies of living communities. Among them are cover, density, relative density, relative dominance, frequency, relative frequency, mean area, etc. (Phillips, 1959). In fossil floras, such information as cover, relative dominance, and mean area cannot be determined (at this time) because the size of individual fossil trees and shrubs normally cannot be measured. However, if the number of leaves are in proportion to the number of plants (trees) in the immediate area, and if the collec- tion sites are treated as though they are "plots", then several 'E .4. . I. RP“ " ‘5» E u“.-; ‘s‘a‘.. - 53 quantitative factors can be determined approximately. These are the following: Relative _ Number of points of occurrence of the species 100 frequency Number of points of occurrence of all species Relative a Number of individuals (leave§)* of the species 100 density Number of individuals (leaves)* of all species *This means leaves, leafy twigs or phyllodes The following data were used for these calculations: in the Swamps there were 142 points of occurrence and 1499 individuals of all species; in the Bottomlands there were 108 points of occurrence and 1430 individuals of all species; and in the Point Bars there were 30 points of occurrence and 287 individuals of all species. This paleoecological information and the data for each species was obtained from Table 6 which shows the number of fossil leaves of each of the 43 important species in each environment. In the analysis of modern Plant communities it is common to determine an Importance Value or Index which usually combines several of the above-listed factors in order to identify the most significant organisms. One example is as follows: Importance Value = relative density + relative dominance + relative frequency (Phillips, 1959) Other formulas are commonly constructed for particular communities or studies (P. G. Murphy, personal communication, 1973). Relative dominance cannot be determined in this study because the size of the plants themselves cannot be determined. 54 Relative _ Total basal area of the species dominance — Total basal area of all species 100 Therefore, the Importance Index of the Blackhawk fossil plants cannot include it. The Importance Index used here is as follows: FOSSIL PLANT IMPORTANCE INDEX = Relative Density + Relative Frequency It should be pointed out that it is unlike the values obtained in living communities and, therefore, cannot be directly compared to them. It does, however, identify those plants which were ecologically signi- ficant in the Blackhawk plant communities. The relative density, relative frequency and the Importance Index of each species are shown in Table 5, where the plants, for comparative purposes, are listed in the same groupings as in Figure 6. It is apparent that certain fossil species have relatively high Importance Indices while others are nearly insignificant. The specimens with high indices are normally those which were found in a majority of collection localities. Some of the problems of using these factors in the study of fossil plant communities are the following: 1. Individual leaves were used to represent entire plants. Although Chaney (1925) indicates a correlation between the number of leaves on the ground and the number of trees, there are probably many variables involved, including the evergreen or deciduous character of the plants, local transporting media, differential preservation factors, the size of the plants, etc., which might affect this relationship. 55 Table 5. The relative frequency, relative density, and Importance Index of each of the important Blackhawk species within the three floodplain environments. Swamps Bottomlands Point Bars 0 OJ 0 Taxa of? o 3 m? o 2 m3 0 3 3:53.33 2.52.53 3.53.33 $332135 3337.333? $33335 337352”? 337.18%? fiflfifig‘g MEI-c MD HH oak. arc: HH can. an H Asplenium dicksonianum 0.7 1.1 1.8 0 0 0 0 0 0 cyathea pinnata 0.7 2.5 3.2 0 0 O 0 0 0 Onoclea hebridica 0.7 2.7 3.4 0.9 0.2 1.1 0 0 0 OBmunda hollicki 2.1 0.3 2.4 4.6 2.3 6.9 0 0 0 Unknown Fern l 0 0 0 0.9 0.8 1.7 0 0 0 Araucarites sp. 0 0 0 0 0 0 10.0 21.6 31.6 Brachyphyllum macrocarpum 3.5 10.3 13.8 0 0 0 0 0 0 Mbriconia cyclotoxon 4.2 2.2 6.4 0.9 0.1 1.0 0 0 0 Nageiopsis sp. 0.7 0.7 1.4 0 0 0 0 0 Podbzamites sp. 2.8 0.7 3.5 0 0 0 3.3 44.6 47.9 Protophyllocladus polymorpha 9.2 5.8 15.0 3.7 2.3 6.0 10.0 1.4 11.4 Protophyllocladus sp. 2 0 0 0 1.9 3.5 5.4 0 0 0 Sequoia cuneata 11.3 32.1 43.4 5.6 1.5 7.1 6.7 1.0 7 7 Widdringtonites reichii 0.7 0.8 1.5 0 0 0 0 0 0 Gyperacites sp. 2.8 1.3 4.1 0.9 0.3 1.2 o o o Geonomites imperialis 6.3 2.9 9.2 3.7 0.6 4.3 10.0 5.9 15 9 Anona robusta 0.7 0.7 1.4 0 0 0 0 0 0 Apocynophyllum giganteum 2.8 0.3 31. 2.8 1.5 4.3 0 0 O Cbrcidiphyllum arcticum 0.7 0.5 1.2 3.7 23.6 27.3 6.7 2.8 9.5 Cissus marginata 3.5 3.5 7.0 6.5 2.7 9.2 3.3 1.0 4.3 Cbrnus denverensis 2.8 1.1 3.9 1.9 0.6 2.5 0 0 0 Cbrnus praeimpressa 2.1 2.0 4.1 4.6 1.1 5.7 3.3 0.3 3.6 DryophyZZum subfalcatum 4.2 1.3 5.5 7.4 11.6 19.0 6.7 2.8 9.5 Dryophyllum whitmani o o o 1.9 2.0 3.9 o o o Ficus Zaurophylla 2.1 0.6 2.7 2.8 0.3 3.1 0 0 0 Ficus planicostata 1.4 0.7 2.1 1.9 0.2 2.1 3 3 1.7 5 0 Laurophyllum coloradénsis 0 0 O 3.7 3.8 7.5 0 0 0 Mbnihotites georgiana 2 1 0.3 2 4 2.8 4.6 7.4 3.3 0.3 3.6 Mbnispermum dauricumoides 0 0 0 1.9 0.6 2.5 3.3 0.7 4.0 Myrtophyllum torreyi 3.5 1.2 4.7 4.6 4.8 9.4 0 0 0 Phyllites vermejoensis 2.1 1.1 3.2 4.6 2.7 7.3 0 0 0 Platanus aZata 1.4 0.5 1.9 1.9 1.2 3.1 0 0 0 Platanus raynoldsii 5.6 5.2 10.8 10.2 11.0 21.2 13.3 2.8 16.1 Rhamnites eminens 8.4 9.7 18.1 3.7 1.0 4.7 6.7 2.4 9.1 Salim gardneri 1.4 1.0 2.4 0.9 0.4 1.3 0 0 0 Salim proteaefblia 2.1 0.7 2.8 0 0 0 0 0 0 Salix stantoni 0.7 0.1 0.8 2.8 0 9 3.7 0 O 0 Viburnum antiguum 2.1 0.2 2.3 1.9 1.8 3.7 3 3 0.3 3 6 Unknown Dicot 2 0 0 0 1.9 11.5 13.4 0 0 0 Unknown Dicot 13 1.4 2.3 3.7 1.9 0.3 2.2 O 0 0 Unknown Dicot 19 1.4 0.5 1.9 0.9 0.1 1.0 6 7 6.3 13 0 Unknown Dicot 25 0.7 2.1 2.8 0 0 0 0 0 0 Unknown Dicot 32 0.7 0.8 1.5 0 0 0 0 0 0 56 2. The sites used in this study are not comparable to those "plots" used in the analysis of modern communities. Typically these sites vary in size, are a measurement of volume instead of surface area, range geographically over a distance of 40 miles (64 km), and vary sufficiently, stratigraphically to indicate they probably were not contemporaneous. 3. There may be more than the three mentioned depositional environments represented in the portions of the Blackhawk Formation examined. There is some reason to believe that the Black Diamond Mine sediments (collection sites 7/23/70 I, 8/28/70 I, 8/28/70.II, 8/28/70 III), are actually deltaic in origin, rather than deposited on a river floodplain. In addition, there may have been a.riparian and a river levee plant community which are both difficult or impossible to identify from sediment analysis. Other fossil plant Importance Indicies are considered in Appendix II. The plant communities of each of the environments are discussed below and, where appropriate, compared to modern floodplain communities of the world today, chiefly Mississippi River communities. In a few cases, plant species which were not represented by enough specimens for them to be added to Figure 6 or Table 5 are mentioned and discussed since they often represent a significant aspect of a particular community. THE ENVIRONMENT OF THE BLACKHAWK SWAMPS It has been pointed out elsewhere in this report that two types of peat-forming swamps have been preserved in the Blackhawk Formation. One type produced the thick, extensive and mineable coals of the lower part of the formation and geographically located in the eastern part of the depositional area. They were near the strandline and must have been brackish water swamps (Young, 1966; Maberry, 1971) in relatively stable basins in which great amounts of peat developed. The second type of swamp accumulation produced thinner and more localized coals in the upper and western portions of the Formation. These swamps may have been several miles from the strandline and were features of the extensive river floodplains. They were probably freshwater swamps subject to the erosional and depositional actions of the meandering river systems. Recent floodplain swamps of this nature have been formed from ox bow lakes or low-lying backswamp depressions where trapped channel water, flood water and ground water can accumulate (Voigt and Mohlenbrock, 1964). The sedimentary and biologic remains of these freshwater swamps were examined in the field and laboratory and are considered here. A few comments relating to the Blackhawk brackish water swamps are included later. Several specific aspects of the Blackhawk swamps are compared to certain features of existing swamps in the Mississippi River Valley. There seem to be many interesting physical and biological similarities as well as a few major differences. 57 58 Arborescent Plants The most significant trees of the Blackhawk swamps, listed by their Importance Index were: Sequoia meata (conifer) 43.4 Rhmrmites eminens (dicot) 18.1 Protophyllocladus polymorpha (conifer) 15.0 Bmohyphyllum macrocarpum (conifer) 13.8 Platanus rayno stii (dicot) 10 . 8 The high Importance Index of both Sequoia cuneata and Proto- phyllooladus polymorpha are unquestionably influenced by the ease with which fossils of these specimens can be identified, even when they are poorly preserved or fragmentary. By comparison it is much more diffi- cult to identify accurately a broad-leaved fossil dicotyledon because better preservation and a physically larger specimen, with leaf tip, margin and base preserved is required. It is felt that a large propor- tion (nearly all) of the conifer specimens in the collection are identified, while only about one half of the dicotyledons could be identified because of poor preservation. In addition, a larger number of poorly preserved or fragmented dicotyledon leaves are probably discarded in the field than are specimens of conifers. Considering these factors, it seems possible that the number of specimens of Rhamnites eminens might be closer to that of S. cuneata while the number of specimens of the other dicotyledons might be as great or even greater than that of P. polymorpha. If this be possible, it appears that S. cuneata and R. eminens may have been co-dominant trees, somewhat similar, though perhaps fortuitously, to forests in existing 59 swamps of the Mississippi River floodplain where bald cypress (Taxodium distichum) and water tupelo (Nyssa acquatica) are-the co-dominant trees of that plant community (Braun, 1950; Gould and Morgan, 1962; Voigt and Mohlenbrock, 1964). It is interesting to note that the foliage of fossil S. ouneata.is much like the foliage of living bald cypress, to which it is thought to be distantly related, while the fossil R. eminens is similar in appearance and habit to the living water tupelo. The subordinant (or less abundant) trees in the Blackhawk fluvial swamp community consisted of the conifers Brachyphyllum macrocarpum, Protqphyllooladhs polymorpha and Mbriconia cyclotoxon, and the angiosperm.PZatanus raynoldsii. Rare or less frequently occurring trees included the conifers Androvettia sp., Metasequoia sp., and Widdringtonites reichii, and the angiosperms Cbrnus praeimpressa, Salim proteafolia, DryophyZZum subfaloatum, Myrtophyllum torreyi, Ficus gZassconea and Manihotites georgiana. Specimens of these plants were collected in one or, at most, a few collection sites, and are interpreted as being of only local importance. Again, the fossil conifer specimens are much easier to identify than the dicotyledons and therefore the Importance Index of the dicotyledons might be somewhat higher if all of the specimens could be identified. Besides the abundant fossil leaves collected, many in situ tree stump casts have been seen throughout the exposures of the Blackhawk strata which have been studied. Undoubtedly some of these casts represent the partial burial of some of the above-listed trees. However, these casts are deformed from lateral compression and little 60 petrified tissue remains except vitrinous rinds. These are generally not identifiable. The original dimensions of such stump casts are hard to reconstruct which makes identification even more difficult. It is interesting to speculate on the size and form of the dominant trees in this forest, since dominant trees in modern plant communities normally are those that are taller, have a greater individual biomass and more leaf surface area than any subordinant tree (McNaughton and Wolfe, 1973). If Sequoia cuneata and Rhamnites eminens were indeed the dominant trees of the Blackhawk swamps, then they may have been very large, perhaps reaching the height of modern swamp trees, which is commonly 100 feet (30 m) (Shelford, 1963). Buttressed tree bases and the growth of pneumatOphores or "knees" are apparently characteristic of most individual conifer and angiosperm species which live in existing swamps (Anderson, 1973; Voigt and Mohlenbrock, 1964). This seems to be a response of annual trunk sub- mergence and does not develop when the same species occur in areas where they are never submerged (Penfound, 1952). Evidence which is discussed later in this study indicates that the Blackhawk rivers flooded nearly every season. Therefore, since the ability to form buttressing and pneumatophores is an inherent, adaptive feature of several unrelated groups of modern plants, there is some basis to look for similar structures on Cretaceous conifers and angiosperms which may have responded in a similar manner to annual submergence. At this time no such structures have been observed in the Blackhawk strata. It is noteworthy that certain living relatives of two Blackhawk conifers prefer nearly the same environment that seems to have been 61 required by the Cretaceous species. These plants are Taxodium distiehum, previously mentioned as a distant relative of Sequoia cuneata, and PhyZZocZadus aspleniifolius, the celery top pine of Australia, which is apparently related to ProtophyZZooZadus polymorpha. Both living species prefer the shallow, wet-acid, peaty soils of flood- plains (Voigt and Mohlenbrock, 1964; Hall g£_gl, 1970), similar to those which seem to have existed in the Blackhawk swamps. Mbtasequoia glyptostroboides, the Dawn Redwood, which is related to Metasequoia sp. of this study, also prefers moist, slightly acidic soils. This tree, however, seems to be a member of stream-side communities (Chu and Cooper, 1950). Other Blackhawk swamp conifers either have no living relatives or have living relatives with different ecological require- ments than those postulated for the fossil communities. It is generally not possible to compare ecological requirements among the angiosperms since the relationships between Cretaceous and modern angiosperm species is usually unknown. Several exceptions might be fossil members of the genera Gercidiphyllum, Cissus, Geonomites, Menispermum, Nymphaeites, PZatanus, and Trapa, explained subsequently. Judging from the great abundance of fossils, particularly Sequoia cuneata and Rhamnites eminens, the trees themselves could have been very numerous. The abundance of mature trees in existing swamps seemed remarkable to Penfound and Hall (Penfound and Hall, 1939; Hall and Penfound, 1943; Penfound, 1952) who counted from 438 to 650 mature trees per acre and point out that this is often twice as many trees per acre as are in mature bottomland communities adjacent to the swamps. They mention that swamp trees are usually very slender. 62 Hall and Penfound (1943) summarized their study of a deep swamp in Alabama and characterized the trees they examined with about the same features imagined for the Blackhawk trees. That is, they were ta11,.s1ender trees which grew close to one another, often to great height, and may have developed buttressed bases and pneumatophores. Shrubby Understory and Vines In most of the Blackhawk swamps there seems to be no identifiable shrubby or herbaceous undergrowth in areas where standing water was present. These elements are often lacking in parts of modern cypress tupelo swamps (Braun, 1950; Shelford, 1963; Voigt and Mohlenbrock, 1964). It is entirely possible, however, that some of the dicot leaves could have been borne on shrubby plants. In the main exposures where stumps have been found, small shrubby axes have not been recognized. In some exposures where palm trunks of smaller dimensions are recognized, these seem to be plants of limited size which grew in low thickets. The most common shrubby understory tree was the palm Geonomites imperialis. It is found in nearly equal numbers in both swamp and bottomland communities, indicating that it may have grown at swamp bottomland margins. These poorly drained but normally terrestrial sites are the normal habitat for several species of modern swamp shrubs. G. imperialis became locally abundant enough to form thickets of many individuals as close as l to 1.5 m apart. One of these palm thickets which was inundated by sandy overbank deposition can be seen in an overhanging ledge at the Water Hollow Road collection locality and is described below. Leaves of G. imperialis were normally shed , u...— it 3.5-s- ~p--o-:ee -h... (In 0') [IKE . I. e'.§" “Vs-es u '01.... ' b ‘3‘ ‘ . N_ Hy; 63 and accumulated around the trunk bases in large numbers, forming "mats" which can be seen at several places. One rock slab observed at Taylor Flat had 8 layers of fronds in sediment which is now only 4 cm thick. Palm leaves were often found in the lower portions of the sandstones which capped a black or coaly shale, suggesting that the erect palm stems and stiff leaves apparently still attached to the stem were inundated by sandy sediment during overbank deposition while they grew on the peaty surface of the swamp. Another shrubby palm, Paloreodoxites pZicatus, had very short, entire leaves and probably had the appearance and general ecological requirements of certain species of Iguanura, which live in lowland forests of Malaya (Whitmore, 1973). A third palm, SabaZites montana, was collected at Taylor Flat in arenaceous, swampy sediments. W. D. Tidwell (personal communication, 1968) reported that a specimen of this palm had been collected in a sandstone in Huntington Canyon. It seems to have required about the same habitat as Geonomites imperialis, but was much less frequent, apparently occurring as scattered, isolated plants. Nageiopsis sp., a small, shrubby gymnosperm, was present at only one site where more than 1000 leaflets of this plant were collected. These specimens were close to one another in the rock matrix and could have been shed from a single plant. Specimens of another gymnospermous plant, Podozamites sp., were collected in a few swamp sites but this plant also seems to have been an infrequent member of the community. None of the dicotyledonous angiosperms collected in the swamps can positively be said to have had a shrubby growth form. 64 Cissus marginata (Vitaceae) was abundant in this community but is thought to have been a liana, closely related and probably similar in appearance to wild grape species (Brown, 1962). Extant species of the genus Cissus are almost all tendril-climbing vines restricted in distribution to warm and tropical climates (Lawrence, 1951). If CL marginata was a vine it would have required abundant large plants in both Blackhawk swamps and bottomlands for support. This species is among those few fossil plants with leaves similar enough to living species within the family that identification is thought to be accurate (Dorf, 1942, Brown, 1962). Grape-like seeds have been collected in Paleocene rocks of wyoming, but were not found associated with leaves (Brown, 1962). Spackman (1949) found seeds and Traverse (1955) found pollen of Vitis and Parthenoeissus in the Brandon lignite (Oligocene or early Miocene). Herbaceous Understory The herbaceous understory of the swamp consisted chiefly of two ferns, Cyathea pinnata and OnocZea hebridica. Both ferns were collected in about half of the sites. From the number of specimens collected, they appear to have been locally abundant. Interestingly, extant species in the genus Gyathea are known as ”tree ferns" because of their tall, slender palm-like growth habit. However, there is no evidence that the fossil Cyathea pinnata was a plant of large size. A living species of this genus, C. glabra, is small in size or "stem- 1ess" and grows directly on the organic substrate of peat-forming swamps in Malaysia (Anderson, 1961). 65 Certain living species of the genus OnocZea are able to tolerate swamp habitats and.areas of acid soil. One species, 0. sensibilis, is an abundant and important member of the herbaceous layer in the cypress- gum swamps near New Orleans (Penfound and Hathaway, 1938), but is widespread and occurs in other habitats as well (Fernald, 1950). Both of these living ferns generally inhabit an environment similar to that postulated for their Cretaceous relatives. A third fern, AspZenium dicksonianum, was so closely associated with the remains of what appeared to be a single fallen trunk or branch of Sequoia cuneata that one must consider the possibility that it may have been an epiphyte on that trunk. This might be similar to several living species within the family Aspleniaceae which are epiphytes in warm, humid areas today (Bierhorst, 1971). Leaves of the fossil were elongate and have the appearance of being able to clasp or wrap around stems. Many specimens were in direct contact with S. cuneata twigs, particularly a thick (2 cm) stem. Few other species were collected at this locality (Water Hollow, Salina Canyon, 8/24/70). None of these herbaceous plants appear to be adapted to areas where the soil surface was covered by water, therefore, they may have been restricted to swamp margins, or existed as epiphytes on tree trunks. Epiphytic plants are common on buttressed bases of living swamp.trees and include many species of lichens, moss, liverworts, ferns, and angiosperms (Braun, 1950; Hall and Penfound, 1943; Penfound and Hall, 1939; Shelford, 1963; Voigt and Mohlenbrock, 1964). Hall and Penfound (1943) note that a parasitic angiosperm (Phoradendron flavescens) lives on swamp trees. It is a reasonable conjecture that 66 the Blackhawk swamp trees may also have supported a variety of epiphytic plants so we should be continuously watching for such plants while collecting. Another substrate on which herbaceous Blackhawk plants might have grown was the surface of floating logs and decaying stumps. Hall and Penfound (1943) observed abundant floating logs in swamps and describe their significance in supporting a variety of mosses and wet-land herbs. Others have reported these floating "micro communities" and point out that decaying tree stumps are also usually populated with herbaceous plants (Braun, 1950). The low level of probability of optimum condi- tions for preservation of both stumps or fallen logs and leaves of g such plants as may have grown on them makes this type of a fossil record little more than a curiosity. Of the angiosperms collected in the Blackhawk swamps, none seems to be identifiable as an herbaceous plant except the aquatic types, which will be discussed subsequently, and perhaps Unknown Dicot #26. All the rest of the dicotyledon leaves, about 80 species, have the appearance of being coriaceous and rigid and are therefore believed to have been produced by woody plants. Unknown Dicot #26 appears to have had a very thin texture but seems, because of the shape of its base, to have been a leaflet on a much larger compound leaf. Its general appearance is unlike any known living dicotyledon observed in this study. Chaney (1924) said that the small number of ferns and other herbaceous plants in the fossil Bridge Creek flora he examined cannot be taken as an indication of their scarcity in the living forest. He 67 suggests that there were many more ferns in the forest but preservation factors were strongly biased against them. Evidence supporting this idea was obtained from the living Muir Woods forest. Here, there were 4 fern species which were very common, some living at the borders of the pools where he made counts of shed leaves, but, only one fragment from each of 2 species was collected. Therefore, although an herbaceous plant might be extremely abundant in a living forest it normally does not become buried by sediment since its leaves are low to the ground (not dispersed by the wind) and not often shed from the plant, but usually dry up and disintegrate while still attached. Chaney (1924) recognized that the Muir Woods and fossil Bridge Creek environments were different from other fossil floras where broad, overbank deposition on floodplains would have an opportunity to engulf and thus preserve more herbaceous plants. If there were several herbaceous dicotyledon or other species in the Blackhawk flora it is reasonable that at least a few specimens of some of them would have been preserved and recognized, since delicate fern foliage was preserved in many types of sediment. Some of the nearly 3,000 individual leaf specimens which could not be identified might have been from herbaceous species. However, though some of the unidentified specimens appeared to have curled or shriveled before burial, all have the general appearance and character of the identified species, so there is no basis for suggesting that any were herbaceous. The apparent lack of herbaceous Blackhawk angiosperms supports the general conclusions reached by others who suggest that plants with herbaceous growth forms did not diversify and become important until the Tertiary (Arnold, 1947; Darrah, 1960). In?" 68 Aquatic Plants It is significant that the aquatic plants found in the collection were obtained in rocks of swamp origin. These include a water lily, Nymphaeites dawsoni,and a water chestnut, Trapa pauZuZa. In addition, several cattail-like leaves (Cyperacites sp.) were collected although it is not certain that this was truly an aquatic plant. Specimens of these plants were not common, but provide additional evidence for the existence of the swamp communities. The depth of water where these plants grew probably could not have been greater than one m because such plants must root in soil under the water (Shelford, 1963). In addition, species of the modern genus Nymphaea require open, well-illuminated water (Shelford, 1963), conditions presumed to be comparable to those required for the Cretaceous species. . No evidence of any free—floating aquatic plants was found in Blackhawk swamp sediments, although several species of ferns and angio- sperms are commonly found on the surface of modern swamps in such abundance that they completely cover the surface in areas where the water is not flowing (Hall and Penfound, 1943; Shelford, 1963). It seems probable that plants of this form existed at some time on some of the Blackhawk swamps, since several species of free—floating Salvinaceae are known from the Cretaceous (Ellis and Tschudy, 1964; Hall, 1975; Matsuo, 1967, Tschudy, 1966; Weber, 1973). Blackhawk rocks have not been carefully examined for megaspores of these plants. The infrequency of aquatic vegetation in these swamps supports a study by Ostrom (1964) who examined the reports of several Upper A I . -. '.-l-. ‘ieA‘HI-n-vu-nr . 69 Cretaceous floras in order to determine the amount of aquatic vegetation which was present as potential food for hadrosaurian (duck bill) dinosaurs. He concluded that there was little evidence for an abundance of soft aquatic and herbaceous vegetation which had long been considered-toube.a possible basic food source for these animals. He suggested instead that these herbivores ate the coarser vegetation of the abundant woody conifers and angiosperms. Several fresh water gastropod shells were collected in rocks which are considered to be of swamp origin. Palm Thickets Stems of a number of buried palm trees, Geonomites imperialis, were seen in an overhanging ledge of gray sandstone (Unit 0) at the Water Hollow collection locality, Salina Canyon. All such stems were buried vertically and extend up into the overlying sandstone (Figure 7). Several of these are about 10 cm in diameter and spaced about 1.5-2 m from one another. All were preserved with an outer rind of carbonaceous material less than 1 cm thick and a central cast of siltstone. Radiat- ing away from the periphery of these stems were compressions of wedge-shaped leaf petiole bases connected directly to the trunk. These petioles.extended outward from the trunk into the surrounding sediment about 20 to 25 cm before being distorted or becoming indistinguishable in the accumulation of other palm leaves. The leaves in such compressed layers were very numerous, overlapping one another, and lying with longitudinal axes in various directions around the buried trunks. A thin, 12 cm, coaly shale lies immediately below the gray sandstone (Unit N) in which the palm stems were rooted. 70 UNIT P SHALE T1 1 7 H\ Palm leaf mats ' fioncealed {: concealed i] l I ‘: Varied ; J -' ‘ —'~"“i':‘; l 1 from SANDSTONE p._ _ 1.;:- 1 UNIT.) 30nt0 Palm axes with attached leaves 50 at bases COALY SHALE Axis can be seen from bottom to 164.. :\ Varied 11111:,HH: . t°p °f "nit Palm leaf from —“”" i ‘(/// mats 40 to SANDSTONE ; _ ;H111:~ _ \El UNIT M 58" ; Palm axis - 1 .——-~>- IA.— _ . __—,_'1 .1 1”-!_1 11111111 (B) Figure 7. (A) Diagramatic reconstruction of units M, N, and O at the Water Hollow Road collection locality indicating the relative size and position of the buried palm trunks (Geonomites imperialis) and palm.1eaf mats in Units M and O. (3) Palm trUfikS (PET and palm leaves (L) in Unit 0 viewed from below as they are exposed in the bottom of an overhanging ledge. 71 It seems apparent that these vertical axes were buried in place as they were rooted on the surface of a peaty swamp soil. The small diameter of the trunks and the vertical exposure of a trunk in Unit M, below, indicate that they were short, not more than 2 to 3 meters tall, and had persistent leaf bases, much like the growth habit of species of the living genus Geonoma (Corner, 1966). The flattened manner in Jim Jest. which the leaves were preserved suggests that they must have remained .- ~ ‘7 quite stiff as they lay on the ground after being shed. Individual leaves measured here were 2 m long. In the living condition this must have made a very tangled thicket since the trunks themselves were only about 2 m apart. Because the stumps are nearly all the same size, they may have begun growth from seed or rhizome the same season, possibly during annual drought, when surface water was absent. It is probable that while they existed, standing surface water was very shallow or lacking. Several species of living swamp palms can withstand saturated soil and even water burial for short periods, but normally they cannot tolerate these environments (Anderson, 1961). This small palm thicket appears to have been buried during overbank deposition. Because there are actually several individual layers of palm fronds in the lower 30 cm of the sandstone, it seems that some dead leaf litter may have been buried as it lay on the surface of the swamp or low-lying bottomland and later some of the leaves still attached to the stems were inundated by several successive floods bearing arenaceous sediment. 72 On examination of the sandstone below (Unit M), remains of another, earlier palm thicket are evident. Although not as well preserved as the one above, there are numerous palm leaves and a single trunk that extends vertically through the thickness of the sandstone, about 1 m. This-trunk is 7 to 8 cm in diameter and also has leaves attached peripherally near the base. A latex cast of leaves was made on the undersurface of this sandstone. The thin, coaly shale under this sandstone indicates another peaty substrate for these palms. Lateral to both of these buried thickets are several horizontal log casts, some as large as 20 to 25 cm in diameter. Exposed portions of these logs were .5 to 1 m long but they must have been much longer in total length. These logs may have been fallen swamp trees lying or floating on the surface of the swamp. Swamp7Conifers One interesting aspect of the Cretaceous swamps is the relatively large number of gymnosperms (chiefly conifers) which occurred together in these communities. One collection site (Pipe Springs, Salina Canyon, 8/19/70) yielded 6 species of gymnosperms which grew within several meters of one another, and two sites (Pipe Springs, 8/18/70 and Cox Swale, Straight Canyon, 7/11/70 11) had 5 species in similar close association. Other sites had fewer species. Several conifers are commonly found in modern swamps and include species in the following genera: Abies, Chamaecyparis, Dacrydium, Juniperus, Larix, Picea, Pinus, Podbcarpus, Taxodium, Taxus, Thuja, and Tsuga. Certain of these species are completely restricted to swamp habitats while others may only occasionally overlap into these {r '_ Q‘Afi-h -—‘ u-J‘ 73 areas (Buell, 1939; Penfound, 1952; Anderson, 1961). H(Draever, it appears that in modern swamp or bog communities there are r arelyever more than 3 or 4 conifers growing together, and when they are it is apparently due to a mixing of representatives of two or more s"HI-ccessionalstages (Penfound, 1952). This large number of Cretaceous conifers seems to reflect the intermediate position of the Blackhawk flora between the earlier Mesozoic floras dominated by conifers and the later Cenozoic floras dominated by angiosperms. Of these conifers, six genera became extinct b efore the end of the Cretaceous Period (Androvettia, Brachyphyllum, Moziconia, Nageiopsis, Podozamites, Widdringtonites), and another genus (Pmtophyllocladus) was eliminated from the Northern Hemisphere late 111 the Paleocene (or early Eocene). Only Metasequoia and Sequoia Q(Dritinued on into the Tertiary in North America, where late in the uretrtiary Metasequoia disappeared from the Western Hemisphere. Though the genus Sequoia is present in North America today, the species S. Quneata disappeared from the record by the end of the Paleocene. Eight cf these extinctions correlate with the disappearance of the extensive fluvial and coastal swamp habitats associated with the Western Interior geaway. This suggests that they were mostly restricted and highly adapted to swamp or wet-acid environments and became extinct when these Qtlvzironments were reduced in size and isolated as the sea receded. host of these species seem to have been restricted to the coastal plains or shores of this seaway throughout the Cretaceous Period. t .H 4h.nuu;-.!.l 74 M Growth, Water Fluctuation and-Depth In describing deep swamp communities, Penfound (1952) mentions that seeds of all woody fresh water species require "dewatering" or - - 8 trandage'kif germination is to be accomplished. Braun (1950) and Shelford. (1961) support this conclusion in their observation of swamps on the Mississippi River floodplain. In order for certain trees, including the bald cypress, to become established, the seeds must sprout when they are not submerged and the seedlings must grow to sufficient" height during the first year to stay above the floods which to ccur the second year (Penfound, 1952). Wells (1942) says that cypress and gum seeds will germinate only in the presence of gaseous oxygen and n01: in water. Mangrove trees (Rhizophora), however, drop young 8 aedlings directly into the mud even though some water may be present. The seeds of this plant germinate within the drupaceous fruit while a t111.on the twig and the young plant grows to a length of several cm. It is reasonable that Blackhawk tree seeds were able to germinate (311137 on temporarily-drained swamp surfaces. This infers that the a‘h‘lamp water level must have been lowered at least often enough for the treesto reproduce themselves. This periodicity in modern swamps is usuallyanannual occurrence associated with the dry summer months ( Penfound, 1952) . The depth of the swamp water where the trees grew was probably ‘18:) similar to existing swamps where it rarely remains deeper than > feet (2.1 m) for long periods or deeper than 12 feet (3.7 m) at the hfiight. of floods. Usually, these trees occur in much shallower water, 2 to 3 feet (.6 to .9 m) deep (Braun, 1950; Shelford, 1963). In 75 addition, floating-attached plants rarely can become established in water deeper than 6 feet (2 m) (Shelford, 1962). Water depth appears to be the major factor in the distribution of Various species of swamp plants and probably was the case with c retaceous species also. w The kinds of rocks seen in the Blackhawk swamp sediments are .. indicative of the soil or substrate upon which the trees grew. These to cks vary from light gray shales and siltstones, which contains a minimum organic content, to coals, which are largely comprised of Q rganic remains. Evidence that the trees were actually living rooted in both the t'1:l_z:1eral and the organic soils is shown by the presence of in situ trunks in sandstones between coals as well as in sandstones which a irectlyoverly coal zones (as described in the discussion of the Cox 3"Vale Swamp, below). Most of the dark shales do not contain identi- f iable roots but perhaps this is because they were formed in a part Q. f the swamp where water was too deep for trees to grow. In some instances the lack of roots in the black shales might be due to thensive decay. A. T. Cross (personal communication, 1975) indicates that roots are 3 Quad throughout the depth of most peat, lignite and coal beds. These )3 oOts are preserved from former levels of plant growth and accumulation Q ince the roots of the living generation usually penetrate less than ‘ '11. He further states that some levels contain few identifiable roots 31:10:13 the plant debris, while other layers contain many roots of 76 varioussizes. Occasional clay, sandstone or siltstone partings in the Coal or peat may or may not have roots present probably due to preser- vation. Huttel (1975) shows that most of the roots larger than 5 mm in diameter-are found within 70 to 80 cm of the surface. He indicates that the clay below 80 cm may actually inhibit root growth. This growth position of living tree roots is significant in the interpretation of the roots in the Blackhawk swamp sediments. The Blackhawkswamp forest trees, buried by overlying sediments which poured in over the standing vegetation, were not rooted in the clay and silt b eneath the swamp but were rooted directly in the peat. This demon- SI Crates, as in modern swamps and marshes, that the roots were chiefly o riented in a shallow, horizontal plane in the upper part of the ‘underlying soil (clay, silt, sand) or peat. As the peat was buried, Q<3'tnpressed, and coalified, the roots became deformed and cannot be distinguished in the coal or coaly shale at this time. This accounts fer the low numbers of roots collected or seen in the field. It could be assumed that the Blackhawk peat—accumulating bogs were acidic, having a low pH similar to most existing swamps, perhaps as low as pH 5.3 (Hall and Penfound, 1943). Some modern bogs are alkaline, but they are apparently very rare (Buell, 1939). Alkaline b 088 or swamps are not characteristic of river floodplains (Penfound, 3‘ 9 52) . Hall and Penfound (1943) mention that the soil in an Alabama QVMP was firm enough to easily walk on, but the soil of a Louisiana Q“Vamp was much too soft (Penfound and Hall, 1939). As a matter of InZerest, abundant dinosaur tracks have been seen and collected from 77 the surface of the mineable coals in the Blackhawk Formation, indicating that the peat of some of the swamps was consolidated enough to support the weight of these large animals. Some animals may have been partially 8‘IHrpported or buoyed up by water inundating such swamps. Casts of d inosaur tracks found in the Kenilworth and Sunnyside mines and in Collections of the Utah Museum of Natural History and the Price Natural History Museum are 5 to 30 cm thick, indicating the animals sank into the substrate at least to that depth. S :Lze and General History of the Fluvial Swamps After examining many of the very thin coals and coaly zones, it is apparent that the size of the fluvial swamps on the Blackhawk floodplain Varied in extent from 50 yards (46 m) to a mile or more and generally were in existence for only brief periods before being covered or modified by the return of the sinuous channels and shifting interfluves cf the Blackhawk river meander belt or upper delta plain. They often indicate a cyclic history similar to that described for the lower L"11:l.szs:l.ssippi Valley and delta system by various workers. These swamps were in local basins such as cut-off river channels, ox bow lakes and interfluve depressions which developed by irregular compaction of much between sandstone channel fills, rather than in the much larger and more stable basins associated with coastal lagoons and off—shore bars in which the Sunnyside and Hiawatha coals accumulated (Young, 1966; Maberry, 1971), Normally, there exists a distinct dark or black shale below and above each coaly zone. This dark shale often grades into a light VI . r—r‘ i‘. l 78 c olored siltstone which in turn is overlain by a sandstone unit of v ariable thickness. The sandstones below the coals are often white. The best fossils are usually found in the shales and siltstones between the coals or coal zone and the overlying major sandstones. This lithologic sequence suggests the creation of a swamp, perhaps through the following processes: a river meander loop is isolated to f orm an ox bow lake. The lake is infilled by silts and clays during annual floods until it is shallow enough that plants encroach upon it and across it. Gradually an accumulation of organic matter or peat occurs. Finally the eutrophic ox bow lake is silted-in with overbank 8 ediments, the vegetation is swamped with silt or sand, swamp conditions 8 ive way to drier site communities and eventually the swamp is complete- 137 sealed by the deposition of sand, mud or silt. Later, if the river makes amajor change in its local channel, channels may again meander across the former swamp site and point bar accumulations mark their In:l.grating course. In other instances the swamp may be initiated by depressions due to compaction of less competent muds between competent e andstone lenses buried below the surface of the floodplain. The history of such a swamp development would differ only in starting as a swamp rather than as a lake or other open body of water. In a number of instances it was observed that a sandstone lay Qirectly over the surface of a coal. This must be interpreted as the e‘Jdden deposition of sand over the swamp, perhaps during a breaching cf levees along the old channel, such that the new channel lay directly upon the peat; or perhaps the river may have poured out sheets of sand and silt (overbank deposits) over the swamp during a flood. In several 79 <2. f these swamp-capping sandstones pea-sized gravel is present indi— cating considerable current action. Many vertical tree stumps can be 8 een inmost of the thinner (2-6 feet or .6 to 1.8 m) sandstone units, and wood pebbles are found within the lower portions of the sandstone indicating erosion of one portion of the swamp, and deposition of the 8 coured out past and sand in another portion of the swamp. The Cox Swale Fluvial Paleoswamp Sedimentary history. -- The sedimentation. coal, and plant fossils found at the collection locality near Cox Swale in Straight Canyon indicate that a peat-accumulating swamp existed here which was repeatedly buried by river overbank deposition. The fossils from the c Ollection 7/11/70 II were obtained here, see Figure 8. The basal member of the section is an 18 inch coaly shale, Unit A (Figure 8). This is the remains of a thicker accumulation of pest and clay, but has been compressed and dewatered, in part, by the weight of the over- lying sediment. No identifiable plant fossils or standing tree stumps can beseen, probably due to deformation during compaction and degrada- t ion of the plant tissue. The length of time for this material to a>Qo::umulate must have taken hundreds of years. Trees were growing on the surface of this swamp. Therefore seasonal water depth never cheeded more than about 7 feet (2 m) (Shelford, 1963) and may normally I‘GVe been much less. This swamp and'the trees growing on it were buried by 40 inches (1 m) of sand, Unit B. This is a gray, fine-grained sandstone with poorly-defined bedding. It does not have the shape of a channel fill 80 Z conceafid { \' ‘ l - 2 ft \ 0.5 m" \\l‘ { UNIT 11 SANDSTONE \ Tr“ _ 1 fl Stumps O‘L o ”l ZN UNIT G SANDSTONE \ ; Tree Numerous S COLLECTION”... Fossil / \’ tump 7/11/70 II Leaves )I ’h _I_n s__itu fern ‘1' n (mg—£5 h_e____bridica) SHALE \ l UNIT F \ j u ,/ x UNIT E J COAL \ I UNIT D [ SANDSTONE ){U’LL Tree n I Stumps UNIT C/ SHALE SANDSTONE Tree Stumps UNIT B L Utah 12‘3”"? UNIT A COALY SHALE r:l.gure 8. Generalized stratigraphic section at the Cox Swale collection locality. The lithologic units have been designated letters A through H, the fossil collection site is indicated, and fossil tree stump casts are shown. m ‘i'i‘m _ txfiimlfltf .J’ 81 and it does not have cross-bedding. In addition, it directly caps Unit A with no evidence of stream-channel scouring of the peat swamp. The tree trunkspreserved in it extend vertically from the surface of Unitkto Unit C. For these several reasons, it appears that this s and was deposited quickly, during a single flood (perhaps in hours o 1’: days) as overbank sedimentation rather than deposition within the :- iver. channel. (An alternative consideration is that Unit B accumulated as overbank sedimentation during several successive annual floods and the bases of the trees were more or less gradually buried to the depth of 40 inches or 100 cm.) The trees thus buried were almost certainly killed as the depth of the sand cut off the oxygen to the roots or the Weight of the sand compressed them in the peaty soil. The tree trunks are thus preserved as vertical casts (Figures 8 and 9). No plant fessils other than these tree stump casts were recovered from this Sand. As compression and sinking took place, the water of the swamp was able to return to its original position. It was undoubtedly necessary for the woody plant community to b ecome established again before large amounts of peat accumulated. Three possibilities exist which would allow the redevelopment of this Q Omanity. The first is that the swamp returned to its original DQSition ascompression and sinking took place. If this occurred, then several successive stages may have been required, similar to those which Penfound (1952) and Sheldon (1961) describe in modern, beat-accumulating fresh water swamps. Their observations suggest that water cannot be more than 2 m deep for these successive stages to begin, because the first group of plants, the submerged-attached 82 (Juli! Figure 9. Vertical tree trunk casts in the swamp sediments at Cox Swale. The Units A through H indicated here are the same as those in the generalized stratigraphic section in Figure 8. 83 plants, cannot survive the low light intensity in deeper water. These plants are succeeded by floating-attached plants which give way to others.in succession until a soil is sufficiently built up. Eventually the woody plants replace the others and remain dominant. Another possibility for the redevelopment of the swamp is that the surface of Unit B may have remained more or less dry but was covered during annual or ephemeral flooding. This would allow the immediate establishment of a woody community and by-pass the long successional sequence required in more or less permanent, deep water. Cross (personal communication, 1975) prefers this alternative to the re-establishment of the woody plants, since there is no evidence of successional stages in the pollen-spore assemblages he has examined in the coals . .A third possibility for the redevelopment of the woody community is that although the sinking of Unit B may have allowed immediate return of deeper swamp water as above, woody plants might have estab- lished themselves during successively dry years while the surface was free from water. As the swamp re-established itself, peat was mixed with a large amount of clay, silt and sand, perhaps indicating numerous small floods. The river may have changed its course and was much nearer the swamp than it was during the accumulation of Unit A. This latest peaty or organic rich mud (shale) accumulation is Unit C. It is well bedded, with an almost varved appearance. Some compaction must have taken place from its original thickness because of the large amount of organic matter in it. The tree stumps originating in Unit A are not 84 visible in Unit C because they rotted away before deposition of Unit C (or were deformed as later compaction occurred). A possible origin of the arenaceous sediment in this unit is the sand of Unit B, below, which may have been scoured up at one place in the swamp and redeposited at this locality. The accumulation of Unit C also represents a long period of time. Trees were growing directly on the surface of Unit C, but no plant megafossils were recovered. The swamp of Unit C was subsequently capped by a thin sand with thickness varying from 6 to 12 inches (15 to 38 cm) at this outcrOp. This is Unit D, and is similar in appearance to Unit B. It is also thought to have resulted from overbank deposition in a single flood. The trees still growing on the peaty surface of the Unit C swamp when sands of Unit D were deposited were also probably killed when inundated by sediments which accumulated to form Unit D. Eventually compaction occurred, the swamp re-established itself, and pest accumulated as before. Unit D is also barren of plant megafossils except for tree casts. Unit E is a coal ten inches thick, representing perhaps 50 to 100 inches (120 to 250 cm) of peat accumulation over the surface of Unit D. Little mineral sediment is present indicating a very long period of uninterrupted organic accumulation. This may represent the longest time period visible in the section. The lack of mineral sediment suggests that the river channel was possibly some distance away during this time, since annual flooding does not seem to have affected this swamp. It is probable that the river flooded many times during the li‘ " 85 accumulation of peat in Unit E (Leopold 35 El, 1964). No identifiable fossils are present in Unit E, but the plants growing on this surface and the surface of Unit F are important in the interpretation of the swamp.flora. These plants were preserved in Unit G, where many were collected and identified. The 12-inch (30 cm) thick coaly shale of Unit F indicates that a large proportion of clay was being mixed with peat of the swamp. The clay could have been derived from overbank river flooding, suggesting a much closer position of the river channel than during the accumulation of Unit E, or by deepening of the swamp by compaction so that seasonal flooding carried clay in suspension into the open swamp waters. Sediment accretion in either case probably resulted from several successive floods which alternated with periods of organic deposition. The bases of the trees growing on the surface of Unit E at the time mud began to accumulate were buried by a minimum depth of 12 inches (30 cm) of mud and probably 2 or 3 feet (.6 or .9 m) of mud before later compaction and dewatering occurred. These trees were still standing and probably alive when Unit G covered Unit F. It does seem apparent that the formation of Unit F may have been much more rapid than the formation of Unit E. The fern OnocZea hebridica which will be discussed subsequently was growing directly on the surface of Unit F immediately before burial by Unit G. This suggests that the surface of F was not covered by swamp water, nor had it been for the length of time required for the fern to become established (at least part of one season and probably several seasons). . I ‘ ‘.:I'FL“~‘-ffin—T 86 Unit G, a 20-inch (51 cm) gray sandy siltstone, covers Unit F. It is apparent that at least the sediment in the lower portion of this unit quickly inundated the existing vegetation, causing plants of Onoclea hebridica and several trees to be preserved in growth position. (This fern and the palm Geonomites imperialis mentioned earlier are the only identifiable plants found in situ in the entire collection.) 0. hebridica was obviously a member of the herbaceous understory and lived on swampy soils devoid of water. Because no reproductive structures were found among the 40 specimens collected here, it is possible that burial occurred early (spring) in the growing season before the fertile fronds developed. This is also the most likely time of year for flooding. It should be noted, however, that Fernald (1950) indicates that the fertile fronds of living species of OnocZea are often not developed. Slightly above the 0. hebridica fossils, but within the lower 12 inches (30 cm) of Unit C, more than 450 leaf and stem compressions were collected. They were generally preserved in a horizontal manner and were often clustered into "mats" of many individual specimens overlying one another. These fossils were found on the bedding planes of the siltstone at many different levels, suggesting that deposition was apparently not in a single short flood, but consisted of several periods of sedimentation. However, this period of time probably was not of many years duration because tree stumps continue through Unit G, indicating that they had either survived partial burial for several years or, they had not rotted away even though they may have been killed early in deposition of this siltstone. The leaves preserved a ”fig. “PF. 87 in this swamp undoubtedly fell from the living trees whose stumps. casts are still present. Compaction again occurred from the weight of Unit G over the lower peat accumulations; swamp waters returned and a period of stabilization followed. Tree trunks from Unit G do not penetrate into Unit B, indicating that they rotted away before Unit H was deposited or were deformed in later compaction.. Trees eventually grew directly on the surface of Unit C, so it can be assumed that some succession must have taken place and the water was not deep if present. These trees are the largest (greatest in diameter) of any seen at this locality. Unit B is a gray sandstone, 4 feet (1.2 m) thick with a well-bedded, platy appearance. This sandstone buried the trees growing on Unit G to a depth of 4 feet (1.2 m) indicating that it too must have occurred relatively rapidly, or the trees would have rotted away. This unit is devoid of any leaf compressions.r At this point, the section is buried by colluvium and it is not possible to deduce further history of this swamp. The sandy and clayey flood-borne sediments which periodically capped peat accumulations in this swamp (Units B, C, D, F, G, and I) seem to have been broadly lens shaped or of variable thicknesses and therefore may have been very local in extent. It is possible that they did not cover the entire swamp, particularly if the swamp was large. Certain areas of the swamp may have been completely unaffected by flood deposition, which moved sandy sediment to this locality, or instead of burial by sand, these areas may have been buried by silts .1. ‘1 ifilnmflt! 88 or clays, lateral to the sands. 0n the other hand, swamp areas peri- pheral to this location could have been partially or completely destroyed by the scouring of flood waters. This may explain the high carbonaceous detrital content of the sandstones deposited above the dark shales; the peat being scoured from one area of the swamp, mixed with sand and redeposited at this site. If these lensy sediments were deposited on only a portion of the 3 i.1‘.u’——A‘.r I swamp, the result would be "split coals." Two such coals exist in roadcuts in the Blackhawk Formation, one at the Water Hollow Road collection site, the other at the Pipe Spring collection site, both in Salina Canyon. A particularly obvious one exists in a roadcut on Interstate 70, 4.7 miles (7.6 km) east of Fremont Junction (south of Emery, Utah) in the upper part of the Ferron Sandstone (Cross gtual, 1975). These split coals result when only a portion of the peat swamp is inundated with sediments; the heavy sediments so deposited, gradually sink as the underlying peat is compressed and the swamp surrounding the sinking area gradually spreads back over; peat accumulation resumes. Such sedimentary lenses form "partings" in the later resulting coal seamt In examining the sedimentation of floodplain swamps, areas might be found with uninterrupted accumulations of peat, while laterally, a thick wedge or "parting" of mineral sediments might be present. Flora of the Cox Swale paleoswamp. -- The collection site in Unit G, 7/11/70 II, yielded about 450 specimens, making it the second largest florule of the collection. More than 30 species have been identified, but only 8 were represented by 10 or more specimens. 89 These species are: Number of Specimens Importance Index Sequoia auneata 207 43.4 Cissus marginata 43 7.0 Onoolea hebridica 40 3.4 Unknown Dicot 25 31 2.8 .Mbriconia cyclotoxon 22 6.4 fihamnites eminens 22 18.1 PhyZZites vemejoensis 13 3 . 2 .DryophyZZum subfalcatum 12 5.5 The remaining species are represented by less than 10 specimens and are arbitrarily disregarded here as statistically minor components of the local community. This florule contains 5 coniferous plants including Araucarites sp. (cone scales), Brachyphyllum sp., Mbriconia cyclotoxon, ProtophyZZocZadus polymorpha, and Sequoia cuneata. It also includes 9 plant species (an unusually large number) which were not collected at any other locality and appear to be previously undescribed. These include: Araucarites sp. (cone scales), Acer cretaceum, Palorodbxites plicatus, and Unknown Dicots 5, 9, 12, 17, 25 and 30. The most important trees were a mixture of gymnosperms and angio- sperms with Sequoia cuneata the most abundant tree. Rhamnites eminens and Unknown Dicot 25 are also important members of the community. Mbriconia cyclotoxon, Unknown Dicot 3, and DryophyZZum subfalcatum were of lesser significance. Two species with small leaves or leaflets, Unknown Dicots l6 and 50, may have been shrubs. The vine, _ _ fl‘c--_..._...._- 90 Cissus marginata, appears to be in unusually high proportions. Palms are represented by two species, Geonomites imperiaZis and Palorodbxites pZicatus, both of which were small and shrubby in appearance. The fern OnocZea hebridiaa was the only herbaceous plant; no aquatic plants were collected. Unlike other Blackhawk swamps, specimens of Sequoia cuneata far outnumber specimens of any other species. Rhamnites eminens was a little less abundant than expected. The soil-like surface of Unit F was not covered by water and may have remained quite dry for some time on the basis of the evidence of the fern in growth position on it. If this period was several seasons in length and it appears to have been, then the clayey substratum could have become similar to certain bottomland soils which would have allowed the growth of nearby bottomland species. If the trees growing on Unit E, below, were still alive or slowly dying because of burial by the clay, leaves of swamp-dwelling trees could have been mixed with leaves of typically bottomland species as they were shed. The presence of 12 specimens of Dryophyllum subfalcatum, an apparent bottomland species, may support this speculation. . f 1;. u. THE ENVIRONMENT OF THE HARDWOOD BOTTOMLAND COMMUNITY Most of the total land surface of recent floodplains is low-lying, not many feet above the surface of the river. These areas are known as bottomlands with soil conditions and a flora which is different than neighboring swamps and river channels (Shelford, 1963; Voigt and Mohlenbrock, 1964). Those floriatic and physical factors which are known about the Blackhawk bottomland are described below. The Arborescent Plants The most significant trees of the Blackhawk bottomlands, listed by their Importance Index, are as follows: CercidiphyZZum arcticum 27.3 PZatanus raynoldsii 21.2 DryophyZZum subfaantum 19.0 Unknown Dicot 2 13.4 These angiosperm species are all represented by more than 100 specimens in the bottomland florules and they all have a relatively high frequency and Importance Index. This community, therefore, appears to have been co-dominated by these trees, much like existing bottomland forests where slight changes in elevation, nearness to the river channel and other factors allow one or another species to become extremely abundant locally (Voigt and Mohlenbrock, 1964), otherwise they occur together in various mixtures. The fossil trees probably formed a forest 91 92 which had the appearance of the modern "hardwood bottoms", adjacent to cypress-tupelo swamps on the Mississippi floodplain, where the canopy is nearly 100 feet (30 m) high and shades a normally sparse shrubby and herbaceous understory (Barrett, 1962; Shelford, 1963; Voigt and Mohlenbrock, 1964). Subordinant but locally abundant trees were Laurophyllum coloradensis, Manihotites georgiana, Myrtophyllum torreyi, and PhyZZites vermejoensis. The conifers Sequoia cuneata and Proto- phyZZocZadus polymorpha were also subordinant trees. Besides the abundant fossil leaves collected, many in situ tree stump casts have been seen in the field, buried within bottomland sediments. Undoubtedly, some of these casts were formed from the burial of the above-listed trees but they are too poorly preserved or deformed to be identifiable. There are a number of characteristics or features of modern 'bottomland trees which probably would have been advantageous to the Cretaceous trees living in such habitats. These include: an ability to thrive on poorly aerated, often saturated bottomland soils; seedlings which can tolerate submergence for several weeks; adventitious root production when basal areas are buried by silt; and very rapid growth (Voigt and Mohlenbrock, 1964). The presence of GercidiphyZZum arcticum in such abundance (more fihan 350 specimens were collected) indicates that it was a significant and perhaps the most important member of the floodplain community. In certain sites it was apparently dominant and seemed to exclude the other co-dominant trees. Its high Importance Index reflects its 7 ~ ‘ ‘1... ‘Ini 93 occurrence in nearly every collecting site. This genus was widespread and diverse in the Cretaceous Period and, interestingly, is represented. by one living species today, Cercidiphyllum japonicum. Its leaves are characteristic as are certain other features which make it unique among living angiosperms. In China and Japan, where it is endemic today, it prefers wells-drained bottomland soils but can tolerate a wide range of soils including wet-acid, swamp types (Numata, 1974). Platanus raynostii is interesting since its leaves closely resemble those of several living species of PopuZus (cottonwood), particularly P. deltiodes which is often a dominant member of the bottomland forest on portions of the upper Mississippi River floodplain (Voigt and Mohlenbrock,. 1964). This tree appears to have been a wide- spread and abundant tree of the Blackhawk floodplain, normally found in bottomlands but occasionally found in swamp communities. Dryophyllwn subfaantum, a supposed live oak-like plant, is one of the most widespread of the Cretaceous angiosperms. Brown (1937) and Dorf (1942) both used it as an index fossil of the late Cretaceous. One of the most interesting plants is Manihotites georgiana. A few fragmentary specimens were collected in swamp deposits, but the species seems to have strongly preferred bottomland habitats. The broad. leaf—blades are the largest of any dicotyledon in the collection, up to 30 cm long and attached to a stiff, narrow petiole at least 18 cm long. At the collection site near the mouth of the Black Diamond Mine (abandoned) in Straight Canyon, more than 20 nearly complete leaves and fragments of about 50 others could be seen. Recently, A. T. Cross (personal communication, 1975) collected additional specimens at 94 severalpoints .along the outcrop near. this locality. At the same placeshe also collected several .fleshyfruits which may belong to this plant. Balsley (personal communication, 1975) has also collected numerous specimens from Blackhawk deltaic sediments in Price Canyon, Utah. In addition, Manihotii'es has been collected in. the Upper Cretaceous Olmos Formation (Maestrichtian) of the Sabinas Basin of northern Mexico near Coahuila (fide Cross, 1973). The original collection of this species was in the Santonian Eutaw Formation of Georgia (Berry, 1914). The infrequency of conifers in bottomland sites further emphasizes that these plants were normally restricted to swampy soils. Only 4 conifer species were collected in these sites and include: Moriaonia cyaZotomon (2 specimens), ProtophyZZooZadus polymorpha (35 specimens), Protophyllocladus sp. 2 (49 specimens) and Sequoia cuneata (22 specimens). The occurrence of these conifers may be explained in several ways. First, they may have been relic trees left at a specific locality as the local sedimentary environment shifted, or secondly, perhaps as individual trees invading bottomlands from an adjacent swamp, or they may have been more broadly adapted to both swamp and bottomland sites. The presence of Protophyllocladus sp. 2 is explained later in the discussionnof the communities at Taylor Flat. The Shrubs and Vines The only. bottomland plant which is known to be of shrub size was the palm Geonomites imperialis. It .was collected in about one third of the bottomland sites, but no thick palm leaf-mats were observed 95 here as they were in swamps. Corner (1966) reports that all species of. the modern genus Geonoma are members of the understory in Brazilian bottomland forests. Four bottomland dicotyledons had very small leaves which may have ‘been.shed.from.shrubby plants.. These species are rare and unimportant members of the community and include: Unknown Dicots 16, 52, 53, and 57. There.are more possible shrubs in bottomlands than in swamps '“B-‘~_ —.. possibly because there was more soil surface area in bottomlands. ‘_‘- Meniapermum dauricumoides, another dicotyledon, was probably a bottomland vine. Leaves of this plant are remarkably similar to those of the living moonseed vine, Menispermum canadensis, a common plant of bottomland forests of North America today (Voigt and Mohlenbrock, 1964). Cissus marginata, a woody vine which was abundant in the Blackhawk bottomlands and swamps, has been described earlier in the section on shrubs and vines of the swamps. It apparently was a more important member of this community than it was in the swamps. Braun (1950) has noted that several woody and herbaceous vines are usually present in the modern bottomland communities. The Herbaceous Understory The herbaceous understory consisted of several ferns, Osmunda hoZZicki being the most frequent. Specimens of this fern were collected in about one third of the sites. Several extant species of the genus Osmunda flourish in wet woodland or bottomland soils and often form an extensive understory apparently similar to 0. hoZZicki (Voigt and Mohlenbrock, 1964). 96 There is no evidence in the bottomland community of the presence of any herbaceous dicotyledons. The Bottomland Soil The kinds of sediments seen in the Blackhawk bottomland strata are indicative of the soil upon which the trees grew. These rocks are chiefly siltstones but they normally have a high percentage of clay or sand.. Some.are highly organic and dark colored, but usually they are light in color with much less organic matter than rocks of the swamps. Barrett (1962) describes the bottomland soils of the Mississippi River floodplain as being composed of fine to coarse sediments in poorly drained sites. In situ stump casts were often observed in bottomland deposits of the Blackhawk, but no root systems were evident. Raindrop prints were observed in the rocks at two sites. For these to have been made and preserved the individual drops must have landed on a soft, fine-textured surface which was free of standing 'water, and was barren of a litter layer and not covered by a canopy of herbaceous plants, but freely exposed. It had not rained enough for water to form puddles at these particular locations since move- ment of water might have obliterated the casts even if they had formed on exposed surfaces. Settling out of suspended clayey material in a.body of standing water could have preserved these splash marks as casts. They might also have been buried by a sheet of water—borne silty sediment, perhaps after a period of hardening or drying. This a 3. “.154-- 97 kind of environment would most likely be found on existing bottomlands rather than in swamps. I The invertebrate trails collected at two bottomland sites were of two types, paseichnia (feeding trails) and repichnia (directed locomotion or trails) (terminology after Seilacher, 1964). Both are less than 1/8" (.3 cm) in width and cover an area of about 6" square. It is probable that they were formed at the bottom of a temporary puddle of water, since there is no evidence to indicate a permanent lacustrine habitat. These trails were collected in the same rock slabs as leaf specimens. Little organic matter is in the rock matrix of the pascichnia and it is unknown what the animal was feeding upon. These features also do not seem to be formed in a peat-accumulating swamp, but, in recent soils, are a feature of bottomland habitats. It seems reasonable to believe that dinosaur and other animal footprint casts should also be found in bottomland deposits as they are in the swamps. To my knowledge, none have yet been collected. Alternation of Bottomland and Swamp Environments at Taylor Flat Characters of the florules and lithology of the section at the Taylor Flat locality indicate repeated development and burial of swamp and bottomland environments. Like the environment of the Cox Swale swamp.discussed above, this locality suggests a dynamic sedimentary environment chiefly due to the constantly meandering river system, compaction of underlying sediments, infilling of backswamps and ox bow lakes and other floodplain activities. Llrrab! L. '-¢“1h 98 .An-idealized.stratigraphic and environmental history has been constructed, Figure 10,.and the sequence of fossil plants collected in the several florules is shown, Table 6. The section begins on the south side of the bed of Salina Creek where the creek passes over a white, finesgrained sandstone, termed Unit A. This sandstone is apparently the top of a fluvial point her. No fossils were collected in this unit. A swamp formed over the surface of Unit A, perhaps as a low.p1ace developed concurrently with the gradual subsidence or foundering of this channel sand into the less competent mudstones below. Units B, C, D, and B were formed in the swamp, indicating the deposition of clay, 4 to 6 feet (1 to 1.8 m) of peat, and finally the deposition of additional clay over the peat, perhaps as the river channel shifted closer to the swamp, thus allowing more frequent flooding. These swamp sediments were all unfossiliferous except for several standing stumps seen in Units B and E. Unit F, an orange, sandy siltstone with little organic matter, was deposited directly upon the swamp. However, it did not sink into the swamp, or, at least the swamp water did not influence the sedi- mentation or the plants which lived concurrently on this unit. This swamp may have been partially drained by the river as it shifted to a much closer position to this locality. The florule collected in Unit F, 7/28/70 11, contains 5 species. The most abundant is obviously a member of the genus Protophyllocladus, but the phyllodes are much shorter, broader and seemingly thinner than P. polymorpha. This may merely be an environmental modification of P. polymorpha caused by burial of the trunk bases of trees living on the surface of he... r " “‘1 99 t?! ~20 ft Fossils g 6 m Q } SANDSTONE Present :9 _"“ P LSHALE No Fossils _-10 O a' 3 clinkers % N SHALE No Fossils ”g4 M f Numerous 3% 7/30/70 IN}— SANDSTONE Stumps & 3.4 0 4-0 7/30/70 II—Ar Leaves 7/30/70 111 L COAL resinous SHALE No Fossils 7/28/70 1(5) umerous 7,28/70 1(2 SILTSTONEP 1mg) Roots & Leaves- an E a: I SHALE No Fossils u .3 ‘5 Ingram“ H SANDSTONE No Fossils .H . o \\\‘ 9. Access V, -o '3: Road m 8 g G Concealed 1% Numerous Fossils ‘E,§ 7/28/70 II F ( SILTSTONE Mostly Protophyllocladus sp. n. E E ONO Fossils 5 Sauna E emanic W. 9° Creek B SHALE No Fossils ‘3 a A SANDSTONE No Fossils Figure 10. Alternation of bottomland, swamp and channel deposition at the Taylor Flat locality. Indicated are the collection sites in the lithologic units, the letter designations (A through Q) of the units, the presence of fossil stump casts and the relation of this section to Interstate 70 and a dirt access road. ....................... 1:1“! .1! as: . -. 100 Table 6. The species and number of specimens collected in the Taylor Flat sites. The sites have been arranged in stratigraphic order such that the lowermost is on the left and the uppermost is on the right. H N In .5: H H H H H H H E 2 f2 2 F3 2 m. s s a s s s a a e 2 a 2 IN N N I'\ IN N Onoclea hebridica 3 Moriconea cyclotoxon l Protophyllocladus polymorpha 2 l l Sequoia cuneata l 2 l :gyperacites sp. 1 Geonomites imperialis 8 6 Sabalites montanus l Cornus denverensis 2 Magnolia amphifolia 2 1 Rhamnites eminens 11 9 2 Seeds 8 1 3 1 Selaglnella sp. 1 Allantodiopsis cross 1 Osmunda hollicki 7 ll 3 Saccoloma gardneri 3 l Woodwardia sp. 2 3 Canna'magnifolia 2 Apocynophyllum giganteum 3 4 14 Cercidiphyllum arcticum 47 142 146 Cissus marginata 2 l 1 3 Dombeyopsis obtusa l Dryophyllum subfalcatum 89 9 5 Ficus laurgphylla ° 1 l Laurophyllum coloradensis 10 17 Laurophyllum meeki 3 Menispermum dauricumoides 8 l Myrtophyllum torreyi 3 Platanus raynoldsii 12 4 52 15 28 Salix lancensis l Traps paulula 1 Unknown Dicot 3 12 5 5 N H 26 1 II II 27 2 1 II N 33 2 l I! H 35 2 II N 52 1 I! II 53 1 Protophyllocladus sp. 2 49 Salix stantoni 5 Unknown Dicot 57 l 101 the swamp which produced Unit F. These trees may have lived for some time after their bases were buried and other swamp species eliminated. Three.other species iannit E are typical bottomland types: Platanus raynoldsii, salix.stantoni, and Cissus marginata. The fifth plant at this locality, Unknown Dicot 57, was not found at other localities and only a single specimen was collected. It appears to be undescribed. The section above Unit F is concealed for about 10 to 20 feet (3 to 6 m) by the recent construction of an agricultural access road and Interstate 70. The section was next observed on the north side of Salina Canyon, about 100 meters due north of the lower portion. At this locality Spieker and Baker (1928) measured the rest of the section up to the base of the Castlegate Formation. Unit H at this position is a thick, massive lenticular sandstone, probably of point bar origin since sedimentary features such as cross bedding and lenticular siltstones are present. The lack of fossils and its low organic content also suggest its origin as an in-channel deposit. After the river abandoned the channel in which Unit H was formed a swamp developed over its surface at least locally, probably due to its foundering in the soft sediment below. This environment appears to have been stable for a great length of time, allowing deposition of the thick, gray shale of Unit I. Although fossils were collected in these shales, they were poorly preserved and fragmentary. The water of the swamp may have been locally too deep for the preservation of complete leaves and twigs. It seems that clays suSpended in overbank flood waters settled into the basin and buried partially-decomposed plants. 102. This swamp was abruptly covered with the coarser sediments of Unit J. The thin beds of this unit are sandy siltstones with a great deal of clay and organic matter. Thin, 1/8 inch (0.3 cm) coals are present throughout as.are abundant plant fossils. One of the most abundant of these was the palm Geonomites imperialis, judging from the number of palm leafdmats present. Another palm, sabalites montanus, was also collected here but it was not abundant. The growth of palms at this location is probably an indication that water did not cover the soil surface as it seems to have done during the history of the preceding swamp. This may have resulted from the lowering of the water level as the river shifted close enough to the edge of the swamp to drain it. The arenaceous sediments of Unit J also indicate a closer river channel. The large amount of organic material in Unit J probably included some which was scoured up from the surface of the swamp as flood waters moved across it. More than 500 fossil specimens were collected at several sites within Unit J. However, since they were so fragmented, only specimens in sites 7/28/70 I-2 and 7/28/70 1-5 were identified. These species were chiefly those of other swamp habitats, including a fern, three conifers, six angiosperms and several unidentified seeds. Few conifer remains were collected,.probably due to the apparent local dominance of Rhamnites eminens, perhaps similar to certain recent swamp habitats where pure stands of living Nyssa aquatica exclude other trees (Voigt and Mohlenbrock, 1964). Apparently Unit J was deposited over a period of time as indicated by the many successive levels of palm mats. No major floristic changes occurred from the time of preservation of the 103 plants in the.lower ten inches of sediment in this unit to the time of the preservation of the plants in the uppermost ten inches. The surface of Unit J supported the growth of tree-sized plants for at least a short time before its eventual burial since many in situ vertical and horizontal roots can be seen. Some were of large propor- tions, extending from the upper surface of Unit J downward, a length of about 4 feet (1.2 m). One root cast was 2 inches (5 cm) in diameter and tapered slightly for more than 30 inches (76 cm) downward. Several circular branch root scars were evident on the surface of this root and casts of branch roots extended away from it. Its general appearance was similar to certain specimens of the Paleozoic genus Stigmaria, but of course no relationship to that extinct group is inferred. These roots post-date the fossil leaves found within Unit J and may be a factor in their poor preservation. This unit seems to have been deposited by a series of floods. Deep-water swamp conditions seem to have returned and formed Unit K, but this dark carbonaceous shale had no identifiable fossils within it. Subsequent to Unit K, 10 to 12 feet (3 to 3.7 m) of peat accumulated, becoming the coal of Unit L. A thin black shale over this coal indicates that the river-swamp relationship had changed, such that much more clay was being mixed with the peat. Capping Unit L is coarser sediment, Unit M. The lithology and fossil plants collected herein indicate the termination of the swamp environment, deposition of a series of arenaceous overbank sediments and the formation of a bottomland community. Again, the river may have shifted closer to this locality, draining the swamps which T‘r‘ :1“?! 4 .1 ‘. s_- .— . an“ 104 produced Units I, J, K, and L, or lowering the water table enough for the development of a bottomland community. The closeness of the river channel probably also accounts for the deposition of coarser sediment. Three.significant bottomland florules were collected in the lower portion of Unit M, each being 10 inches (25 cm) thick. The plants collected in each of these florules are mostly bottomland species, dominated by Platanus raynoldsii, Cercidiphyllum arcticum and Dryophyllum subfalcatum, see Table 6. Several aspects of the develop- ment of the bottomland community on the sandy substrate laid down over the swamps can be seen because the collections were kept distinct from one another. The drier conditions of the bottomland in which the sandy substrate covering the swamp of Unit M was deposited probably terminated the growth of the typical swamp forest. However, two typical swamp plants were present in the lowermost florule, Onoclea hebridica and Rhamnites eminens, as though they were able to survive the change in environment. The fact that they were collected in the first few inches of sediment overlying the swamp sediments and not in-many other bottomland florules (0. hebridica in one bottomland site and R. eminens in five) adds weight to other evidence which indicates that they generally were characteristic of swamp habitats. Another feature of this bottomland community is that Cercidiphyllum arcticum is.represented by 46 specimens in the lowest florule, and more than three times that number in the middle and upper florules. This may indicate that it required some period of time to become established or that it could not flourish in the thinner, perhaps saturated soil 105 immediately over the swamp. Also interesting is the decrease in total number of specimens of both Dryophyllum subfalcatum and Platanus raynoldsii from the lower to the upper portions of Unit M. These trees may have preferred the shallower soils over the swamp or could not withstand competition by C. arcticum. If C. arcticum replaced these two trees in the community, than this may be an example of fossil plant succession. Other sequences where these species occur will have to be investigated to determine the validity of this suggestion. Gonna magnifblia and Menispermum dauricumoides are also restricted. to the lowest florule, but little can be said of other species because not enough specimens were collected to be meaningful. Significantly few conifer remains were collected in these bottomland sediments and no palms. This bottomland community eventually became engulfed by another swamp which is characterized by highly organic clays and peat accumu- lation (Units N, 0 and P). This is capped by Unit Q, apparently another major overbank deposit. No fossils were collected in these units but the resinous bodies in the thin coal (Unit 0) indicate gymnospermic wood, if this compares with similar resinous coals which have been examined in the area (A. T. Cross, personal communication, 1976). THE ENVIRONMENT OF THE BLACKHAWK POINT BARS The point bar sandstones observed in Salina and Straight Canyons are lens or wedge-shaped. The largest, which are commonly 30 or more feet (9 m) thick, taper horizontally and rarely can be traced more than 200 to 300 yards (180 to 275 m), even in nearly vertical exposures . OJUIWJJ I which have no talus accumulation or plant growth to conceal them. ; Laterally, these sandstone bodies are finer grained and have numerous siltstone and shale partings. They taper channelward into sandy silt- ] stones and shales. Spieker and Baker (1928), Baughman (1958), and 3.1 Bachman (1958) all indicate the difficulty of tracing individual sandstone beds laterally for any great distance because they thin laterally and disappear. This lensy feature of point bars in the Blackhawk Formation of the Wasatch Plateau is illustrated in Figure 11. All of these point bars, near the Pipe Springs sites in Salina Canyon, overlap one another; none may be traced along the entire horizontal distance exposed in the cliff here. Casts of logs and water-worn wood pebbles are usually associated with thin lenses of gravel. Many thin lenses of gravel, sand, silt, and clay may be seen within them, similar to such sediments in recent point bars (Wolman and Leopold, 1957). Transported Plant Remains Most of the leaves and twigs collected within point bar sediments were also recovered in both the swamp and bottomland environments. Generally, all were damaged and most of them are preserved lying at 106 107 .so%smu snfiasm aw mwsfiunw seam um cowumanom xsmnxumam emu so seamen saunas emu sfinuas mosoummsmm use mason Hosnenolsfi Hma>aam on» mo ensues henna 05H .HH osswam 108 angles to the normal horizontal bedding, suggesting that they had been picked up by the river from adjacent swamps and bottomlands, transported downstream, and were piled up with some crumpling or distortion on point bars where they were later buried. Shelford (1963) observed this process happening on the Mississippi River, and reported that a great amount of leaves, twigs and wood are annually buried in point bars. The two species which were most commonly found in this environment were Arauoarites sp. and Podozamites sp. These gymnosperms also seem to have been slightly damaged in transport but neither were collected in swamp or bottomland sediments, and do not appear to have been members of those communities. The living araucarians and cycads, the presumed closest living relatives of these plants, are not invaders of the well-washed, often saturated, sandy substrate of point bars. Instead, they prefer mature, well-established stable communities and well-drained, sandy soil with a good deal of humus. They are also slow-growing, unlike those species which are known to invade point bars (Chamberlain, 1935; Hall g£_ai, 1970). Therefore, the origin of these plants seems more likely to have been the piedmont or upper delta plain environment of the Sevier Orogenic belt, near the head of the floodplain. Both the leafy twigs of Araucarites sp. and the leaflets of Podozamites sp. seem to have been durable enough that they withstood transportation by river flood waters without much mechanical abrasion, while the broad leaves of dicotyledonous plants were severely damaged. The araucarian specimens were almost all small twigs and the cycad specimens were all unattached leaflets as though there had been some a .’.‘I. um. :'-A—-E.Tf_ .J‘Q. '. A- 109 sorting action to separate the larger and. more complete pieces from these smaller ones. In contrast, Sequoia cuneata, which was preserved in swamps near where it grew, was represented by both large and small specimens of leaves, twigs, thick branches and cones. No sorting action had separated them. During August, 1968, while at the U. S. Forest Service Desert Experimental Range Station west of Milford, Utah, I witnessed several aspects of conifer transportation by flood waters. Several thousand small, 1 to 6 inch (2 to 15 cm), leafy branches of Juniperous scopulorum were transported by flash flood waters more than ten miles to a plays lake where they were deposited. Upstream from the playa were larger branches up to three feet long many of which were buried within the None of them seemed damaged in any way. Many stream channel muds. ciii-QOtyledon leaves, small twigs and roots of other species were a'380<:iated with the J. scopulorum branches but were generally trans- ported in a damaged and unidentifiable state. It was interesting that all the conifer twigs were green, having been recently removed from living plants. Dead conifer twigs were not observed, perhaps because they were broken into very small particles by the turbulent water. This flood may be somewhat similar to Blackhawk paleofloods which apparently allowed undamaged transportation of Araucarites sp. and Podozamites sp., while other plant species were badly eroded. A possible explanation for certain leafy stems not being signifi- cant-137 damaged by flood. water is that they are carried high in the Water. rather. than under the surface, presumably due to the high water 110 density from its increased sediment load (A. T. Cross, personal connnunication , 1973) . In Situ Plant Remains In spite of the great amount of drift which accumulates on recent point bars, many woody plants do grow rooted in them. In North America these usually include species of willows, poplars or cottonwoods (Shelford, 1963). Older portions of point bars become covered with fine silt and thereafter support a typical bottomland flora (Barrett, 1962) . Three in situ casts of root axes were collected in a sandstone of P01nt bar origin at the 8/26/70 III site in the Ivie area of Salina Canyon. They all were carrot-shaped, about 9 inches (23 cm) long and 2 inches (5 cm) in diameter at the top. Because of their size, they Probably were formed by a shrub or small tree. All specimens had 8eVeral thick secondary roots (or rhizomes) one-fourth inch (0.6 cm) th1CR, which diverged from the main axes extending horizontally several 1“Ghee into the sandstone until they disappeared. These structures may have been adventitious roots formed after repeated burial of the main axis . This type of growth occurs in several modern point bar species (Shelford, 1963). Two of these root specimens were collected at one leVel and a third was collected about 8 inches (20 cm) below, as though it had been buried in an earlier flood. All were collected within two feet of one another as though clumped. None of these specimens could be identified, but they most likely were of a single, angiosperm speclea, similar to willows and other point bar plants which grow in 111 clones. No other root or stem axes which might be interpreted as a member of a point bar community were observed. With the general lack of herbaceous plants in this Cretaceous flora, it seems likely that the river point bars were normally barren of plant growth except for random clumps of woody shrubs, presumably angiosperms . ‘. 1.1“.“ r fining-a? I PROBABLE DECIDUOUS PLANTS Twenty-two of the collection sites exhibited well defined leaf "mats" made up of a great abundance of leaves within a single bedding plane. They usually overlapped one another or were piled such that several could be observed in sediment 1 to 3 mm thick. Numerous species were represented in individual mats. A possible explanation of these mate is that the leaves were shed at roughly the same time, probably at the end of a growing season (see the section of Paleoclimatic Interpretation). They seem to have a(Ectnnulated in local basins near the base of the trees and were buried in Single pulses of overbank sediment before decay had destroyed them. Eight species are of particular interest because they were rePl‘esented by very large numbers of specimens (an arbitrary number of 50) at one or more sites. These plants are the following: Cercidiphyllum arcticum, at sites 7/30/70 I and 7/30/70 II, making up 62% and 71%, respectively, of the total specimens collected at these sites. Dryophyllum subfalcatum, at sites 7/30/70 III and 8/25/70, making up 352 and 18%, respectively, of the total specimens collected at these sites. Manihotites georgiana, at sites 7/23/70 I and 8/28/70 III. (Fewer than 50 specimens were collected, but at least twice that many more were seen at the collection sites on slabs which 112 113 could not be moved.) These specimens are at least 53% and 68%, respectively, of the total specimens collected at these sites. Myrtophyllum torreyi, at site 8/28/70 II where 39% of the total specimens collected were of this species. Nageiopsis sp., at site 8/19/70, where 78% of the total specimens collected at this site were of this species. Platanus raynostii, at sites 7/30/70 III and 8/28/70 I, making up 21% and 53%, respectively, of the total specimens collected at these sites. Podozamites sp., at site 8/26/70 I, making up 97% of the total specimens collected at this site. Unknown Dicot 2, at site 8/25/70, making up 54% of the total specimens collected at this site. Because of the large numbers of leaves of these plants, ranging from 18% to 97% of the total leaves in those sites, they might be identified as those which were probably deciduous. Presumed living relatives of two of these fossil species are deciduous, Cercidiphyllwn japonicum and Platanus spp. Other Blackhawk species may have also been deciduous. It is interesting that all the leaf mats were associated with Va17101.18 types of small seeds or fruits, suggesting that they too were shed at the end of a season. CIOSS 22:11 (1975) report that probable Manihotites georgiana fruits were collected with leaves of that species. A. T. Cross (personal communication, 1975) has said the‘t: ‘these fruits were oval, fleshy, drupe-like fruits about 7.6 cm 1 0'38 and found in the same bedding plane as the leaves. ' H '1" . Up | I! 114 Several ferns and gymnosperms yielded large numbers of individual specimens at single sites, but for various reasons they are thought not to have been deciduous, among them are: Cyathea pinnata, Onoclea hebridica, Arauoarites sp. , Braehyphyllum maerocarpum, Protophyllocladus sp. 2 and Sequoia cuneata. Both ferns may have been buried in situ or at least before the foliage dried and curled up. 6‘. pinnata were mentioned in the discussion of the Cox Swale swamp. The fossils of _ ‘. h“? gal-aw All the conifers except Protophyllocladus sp. 2 are represented by leafy branches which do not appear to be deciduous, since they vary in size and often have numerous lateral branches. The phyllodes of Protophyllocladus sp. 2 have been discussed earlier in the description Of the bottomlands at Taylor Flat. They may have come from a single 8lowly-dying tree which had its base buried. EVIDENCE OF ANIMALS Several fossil leaf compressions show pre-burial damage of the blade or lamina from which irregular patches are missing. Much of this damage is seemingly due to invertebrate parasitism during the growing season perhaps before the leaves were shed. My personal observations of the attached leaves from the ground level to a height of about 12 feet (4 m) in forests of central Michigan and southern Indiana during the first week of October, 1973, and Shelford's observations (Shelford, 1963), indicate that by the end of a growing season virtually all the leaves of herbaceous plants and a 31811:1.ficant percentage of the leaves of woody plants to a height of about 12 feet (4 m) under the canopy are nipped, skeletonized, per- forated, or otherwise deformed. Recognition of taxonomic character- istics requisite for identification is often impossible for some leaVes because of this type of damage. Leaves of the canopy layer at h'33181'1ts up to 80 feet (25 m) were not examined directly, but observation of the detached leaves on the forest floor, which were assumed to come from the upper canopy layer, was made. Fewer of these leaves appeared to be damaged, but still, a large proportion had been grazed. Stulthu-Davidson (1930) has estimated that the population of invertebrates in the canopy layer of a modern deciduous forest is about 15,000 ind ividuals per ten square meters. Of these, there are about 60 species whie-h cause serious damage to the leaves of climax trees (Shelford, 115 “1 H... mg- ‘-I-‘-‘ 116 Because of the damage of Blackhawk leaves, there was, in all probability, a large population of invertebrates in the Blackhawk forests. However, since relatively few Blackhawk fossil leaves seem to have been insect-damaged (compared to the undamaged ones), there may not have been as many invertebrates in these Cretaceous forests as today. In addition. some of the recent host—predator relationships apparently had not developed in the Cretaceous, such as Lepidopteran .- ~T ROQ“'-_$ b- leaf—mining' activities. Hickey and Hodges (1975) report that the earliest evidence of leaf mining Lepidopteran larva is in the Eocene. They suggest an earlier evolution of this activity since it is I“ obviously well developed by that time. However, since it is not identified in the Blackhawk flora it may have originated after the Campenian. Certain holes or spots on leaves examined by Lesquereux (1874), Kn0Wlton (1930), Brown (1962), and others, have been thought to be the result of parasitic or saprophytic fungi because there seem to be fungal remaims present. However, no fungal hyphae or fruiting bodies have been isOlated from Blackhawk leaves. Although many kinds of terrestrial vertebrate animals undoubtedly liVQd on the Blackhawk floodplain, none have been collected. The only direct evidence that they existed are several large dinosaur footprint Casts 1 to 4 feet long (0.3 to 1.2 m), collected in various coal mines. seVeral of these casts may be seen in permanent display at the Carbon County Museum in Price, Utah and at the Utah Museum of Natural History at the University of Utah. Additional specimens may be seen in various r Ock Shops in the area. To my knowledge, no vertebrate skeletal 117 remains have been collected in the Blackhawk Formation. This appears to be difficult to explain since the fossil plant localities are so abundant and represent various types of preservation. Fresh water gastropod remains have been collected by me at the Water Hollow collection locality (Figure l) and marine pelecypod and gastropod remains were collected from two horizons at the Ivie Creek collection locality (Figure l). ‘3 THE WESTERN HIGHLANDS, FLOODPLAIN AND RIVER SYSTEM Mlands and Floodplain Armstrong (1968) indicates that the Sevier Orogenic belt in western Utah and eastern Nevada was the source of clastics for the Blackhawk and other related sedimentary formations. The approximate eas tern boundary of the highland formed by this north-south trending belt is near the present location of Sevier Lake, Utah, about 100 miles (160 km) from the closest Blackhawk exposure. McGookey (1972) indi- cates that the coastal plain during sedimentation of the Blackhawk, during Telegraph Creek and Eagle time, was on the order of 50 to 100 mil es (80 to 160 km) wide in Central Utah. Since the entire floodplain or coastal plain environment at this time extended several hundred miles northward and southward, there were unquestionably many major rivers meandering eastward across this floodplain. The length of the rivers which were in central Utah were on the order of 100 to 150 miles (160 to 240 km) if they originated near the axis of the Sevier Orogenic belt near the recent Confusion Range in western Utah and extended to the shore approximately in the Castle Valley area (McGookey, 1972). \I‘he Rivers One of these major Cretaceous floodplain rivers was the Ferron I“:L\rer, which deposited a portion of the Ferron Sandstone, 5 miles (8 km) Sc3‘.:It:h of Ferron, see Figure 1. This river existed during Carlile time C-J:"-11:'onian) but had the same general relationship to the Sevier Orogenic 118 -;'- w ‘ Own-1- 119 belt and Western Interior Cretaceous seaway as younger Blackhawk rivers but the delta buildup was further southwest than those of the younger rivers. In addition the climatic conditions under which the Blackhawk Formation and Ferron Sandstone were deposited were similar inasmuch as thick accumulations of coal are found in each (Doelling, 1971). Cotter (1971) calculated several paleoflow characteristics of the Ferron River by applying formula derived from recent rivers to fluvial sedimentary features he measured in the Ferron Sandstone. These measurements included the thickness and width of point bars and the tYPe of sediment which composed them. He indicated that the river was roughly 300 feet (90 m) wide, 25 feet (7.6 m) deep and highly sinuous. It -drained an area of about 7000 square miles (18130 kmz) with a mean. a351131181 discharge of about 6,500 cubic feet (184 kl) per second, and an at11111131 flood of about 22,000 cubic feet (623 k1) per second. Inasmuch as several Blackhawk point bars are the same dimensions and sediment type as those in the Ferron, they probably were deposited by a river with similar proportions to those of the Ferron River. It 8.la'fi’l-lld be noted, however, that most of the Blackhawk point bars referred to in the sections in Salina and Straight Canyons are much thinner (than those in the Ferron), probably representing many indi- vidual channels developed in the wide meander belt up stream from the delta or at least further up stream on the delta plain than the Q hannels of the Ferron where studied by Cotter. Cotter's calculations of river flow are also significant in Q 11 mastic interpretations. Since he indicated both annual river dis- Qh area and drainage area, an approximate annual precipitation can be H - ‘1 Wen-unim- 120 calculated. If the river discharged 6,500 cubic feet (184 kl) per second for 11 months and flooded 22,000 cubic feet (623 k1) per second for one month each year, which is about the average flooding period for most rivers (Chebotorev, 1962), then 2.45 x 1011 cubic feet (6.9 x 109 R1) of water was discharged by the river annually. This is equivalent to 15 inches (38 cm) of runoff from the total drainage area (see calculations, Appendix III). Since water runoff in low-elevation, humid, forested areas of the world today is roughly 20% of the total Precipitation (Morisawa, 1968), then the precipitation might have been about 75 inches (190 cm) annually. However, a factor that undoubtedly influences the accuracy of this calculation is the difference in vege- tat ive cover in Cretaceous and modern forests. As pointed out earlier, the Cretaceous soil apparently lacked much herbaceous covering, Particularly grasses. As a result, more water would be expected to run down—slope to streams as it does in modern experimental plots which are barren of plant cover (Sokolovskii, 1971). If this runoff were as high as 25 to 30% of the total precipitation for Cretaceous forests, Iuafilnfall would have been roughly 50 to 65 inches (127 to 165 cm) a‘rldilually, and this may be a more realistic estimate. Cotter (1971) advised caution in the use of his paleoflow data because of many untested generalizations, but it is intriguing to attempt to use such information that has resulted in an approximation Qf annual precipitation which is generally consistent with the climatic 3 ac tors determined from other types of evidence within the period when t his flora was extant. 121 Schunn (1968) suggests that before soil stabilization by modern Vegetation (presumably grasses and herbaceous dicots), the hydrologic situation in ancient valleys resembled thatof modern semiarid regions. Thus it is possible that the paleoflow relations in humid regions in late Cretaceous time were relatively closer to those of semiarid and subhumid climatic areas where runoff is often less than 5% of the total precipitation (Morisawa, 1968). This may well have been the situation in- the piedmont and western (upper) coastal plains of the Blackhawk River drainage areas but probably was not the case on the lower flood- Plain. Sokolovskii (1971) indicated that calculations of annual Precipitation using modern river runoff data are not consistently reliable. However, he was attempting to develop equations which cerrelate, within a few millimeters, modern precipitation and runoff, whereas a more generalized statement of paleoprecipitation is satis- fa.ctory in this study. Meriodicity of Flooding Wolman and Leopold (1951) examined flooding records of 37 rivers of various sizes in the United States and India. For 26 of these rivers, those which had formed a well-defined flood plain, the recurrence interval of overbank flooding was 1.6 years. The other rivers often had much longer intervals between flooding which varied f3:011: 2 to 200 years. However, some of these were identified as '0 u‘Ountain torrents" in northwest Wyoming and their floodplains were difficult to define. A use- I'm-n...— - ' n "'7‘ - I F .r 122 In more recent work, Leopold, Wolman and Miller (1964) indicate that river flooding on a world-wide basis occurs at an average interval of 2.33 years. Therefore, it seems clear that flooding and resulting overbank deposition is a characteristic feature of all existing rivers and must have been a near-annual feature of Blackhawk rivers also. This regular flooding allowed overbank sedimentation and subse- quent leaf burial so important to this study. ‘nu-T THE COASTAL NON-FLUVIAL SWAMPS A small florule of about 75 fossil plant specimens has recently been collected at a single site by J. K. Balsley in what he identified as deltaic sediment between the Castlegate A and B coal beds of the Aberdeen Member in Price Canyon. It is composed of several species of dicotyledonsand one conifer. My preliminary examination suggests that it appears to be dominated by the large peltate leaves of Manihotites georgiana and the leafy twigs of the conifer Moricomla cyclotoxon, with several unidentified dicotyledons as apparent sub- Ordinates. The abundance of both Manihotites georgiana and Moricomla cyclotoxon and their well-preserved condition suggest that they had not been transported, but were probably members of the local deltaic Plant community. This florule, although small, is unique since Manihotites georgiana and Moricomla cyclotoxon did not occur together in any of the fluvial swamps or bottomland communities (see Table l) and the s‘Jbordinate plants are species which are apparently not even present (or at least are not common) in the floodplain communities. In addition, no fluvial swamp dominant plant is present such as Sequoia cuneata or Rhamnites eminens, nor are any other conifers although they were in great abundance in the fluvial swamps. Therefore, based upon the flora of this single site, it appears that there is a major floristic difference between the plant communities on the Blackhawk floodplain and the Blackhawk delta. 123 124 These deltaic plants probably are among those which contributed to the great amount of peat which accumulated at times to make the economically important coals of the lower and eastern portions of the Blackhawk Formation. Some of these coals are greater than 15 feet (3 m) in thickness (Doelling, 1972) and therefore represent great amounts of time . In a petrographic analysis of the sunnyside coals, Thiessen and Sprunk (1937) reported that the coal was partly made up of the wood, leaves, and seeds of coniferous plants. The fact that Moricom'a cyclotoxon has been found to be an apparent member of the deltaic comwnity suggests that it was one of these coniferous plants. Recently, Maberry (1971) indicates that this coal was chiefly composed of plant debris including abundant spores, pollen and waxes, rather than a great an101nm of woody material. Because modern deltaic environments are commonly brackish or are at times brackish, it may be assumed that the Blackhawk deltas were a:LBO occasionally saline. This may have been the factor which limited or restricted the fluvial swamp communities and kept them from inhab- iting the delta. Modern cypress-tupelo forests can survive mildly brackish water, but are killed when the salinity reaches 0.6% (Penfound, J‘952). Interestingly, when recent cypress-tupelo forests are killed with brackish water, they are usually replaced by grasses or other monocots which eventually form a marsh (Penfound, 1952), unlike the apparent woody plant counnunity which existed on the Blackhawk delta. In the discussion of both Mamihotites georgia'na and Moricomla Qz’c’zotoawn in the fluvial floodplain swamps and bottomlands above, it 125 was assumed that these plants were subordinate members of these communities. However, because they are now known to have existed on the delta, the specimens collected in floodplain communities may represent infrequent invaders from a larger population on the adjacent delta. ' V . . - 4,. _ I “:0.‘ Emu uric y.“ 1 ‘ldl ' I $126. I .“ I.‘c‘ a? '3 L. J c;‘ ’ 5“: . PALEOCL IMAT I C INTERPRETAT ION gossil Leaf Physiognomy Bailey and Sinnott (1915, 1916) and Sinnott and Bailey (1916) recognized that a rough estimate of paleoclimate might be determined by assuming that fossil dicotyledon leaves which exhibit certain morphological features probably existed in past climates similar to those in which modern dicotyledons with the same leaf features live. Preliminary data was collected by them which indicated that leaves of many woody dicotyledons have entire margins in tropical, artic and Xeric regions, while taxa in temperate regions have a high prOportion of leaves which are non-entire. Leaf margins and other aspects of foliar physiognomy have been used by several workers in the examina- tion of Cretaceous and Tertiary paleoclimates. These include Bailey and Sinnott, 1915; Endo, 1934; Chaney and Sanborn, 1933; MacGinitie, 1937, 1969; Dorf, 1938, 1942; Edwards, 1955; and Bell, 1957. Recent renewed interest in the refinement of leaf physiognomy as a tool in determining past climates has been undertaken by Wolfe (1969, 1971) and Dilcher (1973). Both authors present information indicating that the relationship between physiognomy of modern leaves and climatic 2°ties is unquestionable, but more complicated than at first suggested. Entire leaf margins. -- Although more investigation is necessary to determine all factors involved, Dilcher (1973) points out that a fairly direct correlation exists between climates with certain 126 o 'ng-Iu‘ Juan“ ML- 5 1.5 A e acplzc‘fiqr. 5 a Gd Q O 5» A'- an» I.- .H.‘ I. an I .5- r» ’ESK 127 temperature and rainfall ranges, and entiredmargined dicotyledon leaves. He shows that leaves with entire margins range from 86% in tropical rain forests of Malaya to 102 in mixed northern hardwood forests of Manchuria. My own studies of the leaf margins of 84 species of woody dicotyledons in Sanford Natural Area on the Michigan State University campus in Central Michigan indicate that 152 have entire margins (see Appendix V). After analyzing available information on temperature, rainfall and leaf margins, Dilcher (1973) wrote: ... the percentage of entiredmargined leaves decreases as the climate cools, dries or cools and dries. In paleo- climates it is often impossible to distinguish between the part temperature and moisture played in producing types of leaf margins since both factors have similar effects. Those zones having 55-1002 entire margins have either high levels of temperature and varying moisture or high levels of moisture and varying temperature. Only those zones which have both reduced levels of temperature and moisture have lower percentages, 10-50Z, of entire-margined leaves. The number of entire leaves in the Blackhawk flora are listed in Table 7 and Appendix VI, and will be discussed subsequently. Leaf nervation, thickness, drip points, vein patterns and epidermal features. -- Observations of extant floras indicate that other features of leaf morphology probably are a response or adaptation to climate. These include leaf size, which will be discussed in detail below, leaf nervation (pinnate or palmate), leaf organization (simple or compound), mesophyll thickness, and the presence of dripping points or attenuated aPicies. The proportion of these features in the Blackhawk leaves is shown in Table 7 and Appendix VI. a-P'"‘ -:a"5 , Q on ' 5'. OH :e:;=era -. s 00' a OQDDOC I I an. ... ' Vielcu‘ c. F ‘Ia. h‘d . 3.1: a! cf 1:, ‘ v... . cg: (a '- U‘A . ...“ 128 It is thought that high proportions of compound leaves with pinnate nervation, thick mesophyll, and drip points are most abundant in trOp- ical lowlands and decrease proportionately toward subtropical and temperate regions (Chaney and Sanborn, 1933; Dorf, 1942). However, little or no quantitative data of leaves in extant forests has been obtained, and until it is, the true relation of these features to climate is unknown. Microscopic features such as the size of marginal areolae formed in the ultimate venation, number of stomata, morphology of the stomatal apparatus (e.g., the presence of cuticular lips, sunken guard cells, stomatal crypts, etc.), multiple epidermal layers, thick cuticle and the presence of numerous epidermal trichomes or scales, may also be adaptations to specific climatic factors (Esau, 1952; Dilcher, 1973). But again, no quantitative data have been collected on the relationship of microscopic leaf features and climatic factors. Most of these features could not be observed in the Blackhawk leaves, due to the apparent lack of cuticular and cellular preservation, and therefore have not been used in climatic analysis. Leaf-size analysis. -- Several workers have shown that the wet tropics are characterized by a high percentage of large leaves but the percentage of large leaves decreases toward cooler or drier climates (Cheney and Sanborn, 1933; Dorf, 1942; Webb, 1959; Richards, 1966). Therefore, leaf size is also, in a general way, a measure of climate. Dilcher (1973) recently has summarized most of the available informa- tion on the relationship between leaf size and climate. He says that 129 the same problem exists in the use of leaf size classes, to determine ancient climates, as with the use of leaf margins, that is, trying to separate the influence of temperature and moisture on leaf morphology. Raunkiaer (1934) established several leaf size classes according to surface area in his studies of moderanuropean forests. Later Webb (1959) modified them into a more workable form for studies in the tropics. They are as follows: Leptophyll 0.0 to .25 cm2 Nanophyll 0.26 to 2.25 cm2 Microphyll 2.26 to 20.25 cm2 Notophyll 20.26 to 45.0 cm2 Mesophyll 45.1 to 182.25 cm2 Macrophyll 182.26 to 1640.25 cm2 Megaphyll 1640.26 cm2 up Dilcher (1973) demonstrates quite clearly the reduction of leaves in the smaller size classes in response to reduced levels of tempera- ture and/or moisture. He also shows a larger proportion of leaves in larger size classes as temperature and/or moisture are increased. His figure 5 (p. 31) can be used as an index of paleoclimate when leaf size classes of fossil plants are compared to it. (Note, there is an error in the caption of Dilcher's figure 5, which should read, "... the average per cent of each leaf-size class is given from right t°.lE£E°") Table 7 summarizes the percentage of Blackhawk leaves in each of the Raunkiaer leaf size classes. See also Appendix VI. No fossil leaves were found in the smallest are largest classes (leptophyll and megaphyll), therefore they have been omitted. .rfla.‘ b 'b‘ 1 I‘ .- “6:; 45a ..." ‘5‘.“ 130 Table 7. Percentages of all 82 Blackhawk species of dicotyledons showing selected aspects of physiognomy including size. (This information is taken from Appendix VI.) Entire Pinnate Coriaceous Drip Margins Nervation Texture Points 722 78% 452 33% Leaf Size Classes Nanophyll Microphyll Notophyll Mesophyll Macrophyll 9 41 to 53 20 to 32 15 to 17 l Problems associated with using leaf physiognomy. -- WOlfe (1971) and Dilcher (1973) have discussed several problems and inconsistencies seen in the use of certain features of leaf morphology in the deter- mination of paleoclimates. Such factors as probable under—representa- tion of large fossil leaves due to fragmentation before burial, possible over-representation of leaves from stream-side plants, the relationship of leaf physiognomy to high altitude temperate areas in low-latitude tropics, and variations of leaf size classes within small sampling areas of extant forests. Although certain problems might remain' unsolved, both workers are convinced that leaf physiognomy is important as an independent method of determining paleoclimate. Dilcher (1973) concludes: As the relationships of leaf form to the physiology of the plants and the variability in climate, solar radiation, and other factors become known, foliar physiognomy will become an increasingly important tool for paleoclimatic analysis. 131 Application to this flora. -- The Upper Cretaceous Blackhawk flora has a fairly high proportion of leaves which have pinnate nervation, an evident coriaceous texture, and dripping points (see Table 7). Since no standards of thickness have been established, the determination of texture was arbitrarily based upon my own judgment. Similarly, any leaf which exhibited a reasonably long, acute apex was considered a drip tip. (This feature was often impossible to determine because many leaves were preserved without the apex. These plants are indi- cated with a question mark, Appendix VI.) The above features all suggest that the climate was probably warm and moist. However, since none have been critically evaluated in living forests, no quantitative comparisons can be made in order to determine a more detailed description of the paleoclimate. The Blackhawk flora is also characterized by a fairly high propor- tion of leaves with entire margins, 72% (Table 7). In comparison to Dilcher's latest summary of the physiognomy of leaves of living plants (Dilcher, 1973, table 1, and figure 4), floras with 72% entire leaves exist only in very warm climates which range from "warm temperate-rain", to "tropical-rain", and "tropical-seasonally dry." Included, of course, are "subtropical" climates, and probably include "subtropical- seasonally dry" although he gives no leaf margin data for this climate type (Dilcher, 1973, figure 4). The percentages of Blackhawk leaves in various leaf size classes similarly indicate a warm climate. They most nearly approximate the leaf size classes in "subtropical-seasonally dry" climates but clearly 1‘; 1‘. g a ...-I .—.»A n n .o an .. 5.1.1 I I u‘vu. i ~t... ad.- is“: file A . b. “a 5“ .4 '_ f‘l) 132 are not like floras in any other subtropical, tropical, or warm temperate climate (Dilcher, 1973, figure 5). As a summary of the use of leaf morphology in the determination of ancient climates, Dilcher (1973) says: ... none of the techniques used in this analysis are yet sufficiently developed to provide an absolute basis for an exact description of the paleoclimate. The state-of—the- art in interpretation of paleoclimates from plants fossil material is at a level to provide good approximations only, with the expectations that our ability to interpret past climates will improve as more precise data on the nature of fossil and modern vegetation becomes available. A comparison of the_physiognomy of swamp and bottomland leaves. -- Penfound (1952) indicated that certain deep swamps of the south- eastern United States were characterized by woody plants with sclero- phyllous leaves. Furthermore, he states that swamp forests cannot be considered normal climax communities because they are controlled by water depth rather than any climatic factors. If this is true, then the Blackhawk swamps might have had a different proportion of leaves in the several Raunkaier leaf size-classes than the bottomlands. At this time, no information is available on possible differences between leaf size classes of existing forests in swamps and adjacent bottom- lands in any climatic zone. Therefore, in order to determine differences which might exist between the fossil swamp and bottomland forests, the plants which seem to be most characteristic of these environments were identified (Table 12, Appendix IV). The total number of plants with entire margins, the leaf size classes, and other features were determined and are listed in Table 8. ‘- .53... 1 isn‘t-ha :eris:ic 51.7.; p: I 3.3» . ‘ b“! .1 5:3 Paint b dorm ( i. . rcznt \ E}, 133 Table 8. Percentages of dicotyledon species in Blackhawk Swamp, Bottomland and Point Bar environments having the same leaf charac- teristics as those in Table 7. No. Entire Pinnate Coriaceous Drip Species 'Margins Nervation Texture Points Swamp plants 60 77 78 50 37 Bottomland plants 49 67 77 51 41 Point bar plants 13 50 64 64 43 Leaf Size Classes No. Nano- Micro- Noto- Meso- Macro- Sp. phylls phylls phylls phylls phylls Swamp plants 60 2 43 to 58 17 to 33 17 to 23 2 Bottomland plants 49 12 33 to 47 20 to 38 14 to 18 2 Point bar plants 13 0 35 29 7 0 Rather than there being any obvious differences in the leaf physiognomy of the two environments, they are surprisingly similar. The largest differences were 10% fewer plants with entire margins and about 10 to 20% more plants with small leaves (nanophylls and microphylls) in bottomlands than in swamps. These differences are apparently not significant in the identification of ancient climates and therefore separating the Blackhawk plants into environmental groups did not aid in the climatic analysis. Even when certain plants from one habitat were eliminated because they seemed to be slightly 134 more significant in the other habitat, all the values for entire mar- gins and leaf size classes remained nearly the same. This may indicate that the climate on this coastal plain during the later Cretaceous was not a significant factor operating in the control of swamp vegetation. It may have been a factor, however, in the control of the leaf morphology of the plants of the several local environments. Climatic Requirements of Livingugelatives A few studies of Cretaceous floras have based paleoclimatic determinations upon the climates of the supposed closest living relatives of the fossil plants (Dorf, 1938, 1942; Parker, 1968). This technique assumes that the fossil plants are correctly identi- fied and have living relatives to which they can directly be compared. However, Dilcher (1973) mentions that in the Puryear Eocene flora which he has been examining in critical detail, 60% of the fossil leaves which had been previously named had been referred to incorrect extant genera or apparently belong to taxa which are extinct. If this is true for Eocene plants in general, than it is undoubtedly also true of the older Cretaceous plants. Dilcher (1973) says, "In any floristic study in which the climatic interpretations are based mainly upon modern affinities the reliability of the interpretations depends on the accuracy of the identification." Dilcher (1974) presents an excellent discussion of the problems involved in the identification of Cretaceous and Tertiary plants, chiefly dicotyledons. He also proposes methods for determining the true I I .A no . - s. .6! . ..-' :.E.3 V .L t the a I .5 I; 35' 3136 135 true identity of fossil plants chiefly through a systematic examination of leaf venation and epidermal features. Because the generic names previously given to many of the fossil angiosperms of the Blackhawk Formation may erroneously indicate that the fossil is related to extant genera, I feel that it is inappropriate to make paleoclimatic conclusions based upon the climatic requirements of the supposed nearest living relatives. Other Cretaceous studies in which paleoclimate is determined in a similar way should be viewed with caution. Reference has been made earlier to several plants in the environ- mental interpretations of swamps and bottomlands. These genera include: Cércidfiphyllum, Cissus, Cyathea, Menispermum, Matasequoia, Nymphaeites, Onoclea, Platanus, Protophyllocladus, Sequoia, Trapa. It is my opinion that these plants in particular, plus certain others not listed here, are identified correctly and do have affinities to extant genera. Seasonality of the Blackhawk Climate A single specimen of lignitized gymnosperm wood collected by me at Water Hollow Road (the "Base of Road Cut" site) and several pieces of petrified gymnosperm wood collected by others in Tommy Hollow (W. D. Tidwell, personal communication, 1970) show distinct growth rings. A. T. Cross (personal communication, 1975) indicates that vitrinized wood in the Blackhawk coals also show periodicity of growth. These Blackhawk woods were either growing in the loose alluvial soils of the upper floodplain and interfluves or on the poorly-drained or Ip.- " “1.36: 136 saturated soils of the bottomland or swamps. It is conceivable that dry seasons could cause the water table on the higher ground to become low enough to allow formation of growth rings in the trees. Similarly, the water (level of the swamps and the water tableof the bottomlands could be lowered sufficiently for seasonal dry periods and resultin differential growth of xylem. It has been established earlier that the Blackhawk swamp trees probably had very shallow but broad root systems, not deeper than 2 to 3 feet (1 m). Since water levels of existing swamps in seasonally dry regions fluctuate at least 3 feet (1 m), it is probable that the Blackhawk trees could have been affected by an annual water drop and therefore had periods of growth and dor- mancy. Since none of the wood was collected in place, it is possible t:hat it originated in or nearer the mountains where a cool-warm season Inight be more significant in effecting growth than on the low-lying floodplain. Leaf "mats" discussed earlier, which seem to be composed of large quantities of shed leaves, also indicate a seasonal climate. Another study of Mesozoic sediments in the Rocky Mountain area also indicate a definitely seasonal climate. Moberly's (1960) study of the Upper Jurassic Morrison and Lower Cretaceous Cloverly Formations in Wyoming and Montana suggest that the climate was hot with a fairly high annual rainfall interrupted by brief (2 to 3 month), but pronounced, dry seasons. This interpretation is based upon numerous layers of lacustrine carbonates present in these formations. No such carbonates eat:lst in any of the Upper Cretaceous Mesaverde formations. 7‘"? n6.»- 1,30va 137 Thayne (1973) has examined three species of petrified dicotyledon- ous wood from the Lower Cretaceous (Aptian or Albian) Cedar Mountain Formation near Castle Dale and Ferron, Utah. Since there were no growth rings in any of the specimens and since the size of the xylem vessels was consistent throughout individual specimens, he suggested that the climate was relatively constant and probably trOpical. It appears from these studies that the climate of the late Mesozoic in the Montana-Wyoming-Utah area fluctuated from warm-season- ally dry in the late Jurassic, to a warm-nonseasonal climate in the early Cretaceous, and then back to a warm-seasonal period by the Upper Cretaceous . Wasted by Other Cretaceous Floral Studies Based upon the physiognomy of fossil leaves collected in the Upper Cretaceous (Maestrichtian) Fox Hills, Lower Medicine Bow and I‘atlce Formations of Wyoming and Colorado, Dorf (1938, 1942) concluded t"flat the climate was subtropical to warm temperate. Ostrom (1964) need Dorf's studies and several other Upper Cretaceous floras in a 8‘llilluary of vegetation types. He concurred that the climate was most likely warm and seasonal. By the Paleocene, Brown (1962) was of the opinion that the leaf floras he examined were controlled by a warm, temperate climate, but he accumulated no data to support this, other than the observation that a seemingly large proportion of the living correlatives of the f 08811 plants are restricted to warm, temperate areas today. For comparative purposes, leaf size classes of selected Upper Q hetaceous, Early Tertiary, Late Tertiary and extant floras were .I 31.13! ._ . . a a S! -7: S?56 138 determined, Table 11. These compilations indicate a general decrease in leaf size from the Campanian (Late Cretaceous) to the Miocene (Late, Tertiary), thus-supporting the gradual cooling trend suggested by Dorf in a series of studies of paleoclimates (Dorf, 1959, 1960, 1964, 1969). Summary .of‘ Paleoclimatic Information Several independent methods have been used to suggest that the Blackhawk paleoclimatewas warm and seasonal, most likely subtropical seasonally dry. It seems that the most significant method in the determination of the climate is the large proportion of leaves in microphyll and notophyll leaf size classes. Living floras with Similar proportions of leaves in these classes occur only in sub- tropical, seasonally dry climates. The large number of species of Plants having leaves with entire margins also suggest a very warm climate during the Campanian stage. Several plants which probably can be considered to be living relatives of the Blackhawk plants currently live in very warm regions with seasonal changes, supporting the conclusions given above. Differential growth in lignified, coalified, and petrified Black- hawk woods are undoubtedly annual growth rings which indicate a clef:Lnite seasonality to the climate, unlike trees which live in 1:2'1‘C>I:bical moist climates today which generally show no growth rings. AC QLnnulations of apparent seasonally-shed leaves as "mats" also imply a ea-sonal changes of temperature, moisture or both. As indicated earlier in the discussion of the Blackhawk river 8 ya tem, p. 121, the average annual local rainfall may have been from lfiflu‘g. 575? be: c teat: v... 139 50 to 65 inches (1650 to 1900 mm) in order to form the fluvial sedi- mentary features which can be seen in the Ferron Sandstone Formation and the Blackhawk Formation. Although all of the factors necessary have not been determined to calculate more accurately the rainfall by the nature of fluvial sedimentary features (i.e., amount of runoff, evapo-transpiration, etc.) it is interesting that such evidence has been compiled which completely supports that given above from analysis Of fossil plant remains for estimating some of the principal climatic features of the Upper Cretaceous in this area. It should be emphasized that the studies of the Blackhawk flora Confirm and supplement those paleoclimatic examinations which have been made by Dorf (1959, 1960, 1964, 1969), Wolfe and Hopkins (1967), AJ'Kelrod and Bailey (1969) and Wolfe (1971). 140 qumH .sunosmomz m NH He mm o as a mHuuHHc oon ouumsm anonuuoz o Hm mm Hm e em H> stcmha< momv ammHHUHz Hmuuaoo mmHOHh quuxm HmmmH .couHox< o o as em a H s amamnov Human nuxusm Hman .uonHoxa o a NH Ha m a s amassov nuns: waHxaHum HmmmH .vonHox< o m as me n a w essence aHaucaoz msHm o m as mm o a HmmmH .wouHox4 a emamaov Hmommz meuoam muefiuuma mama o n NH Ha NH so HmoaH .mHnHaHoumzv n6>Hm cameo o mm me RN 0 Nn AmmmH .anopamm s emamnov cosmos o em on mm m we HommH .aoanoaev schema meuoam muefiuuma maumm H mH Hm on o NH HommH .aonHaoasv hm>amo o mH mm as m oq HNeoH .Huonv 66amH N mH mm mm N as HmmmH .muoac .uuo .mHHHm xom H HH on mH Hm oh ON mm on He a ma Hunoamn mHnuv xaasxomHm mmHOHrm mfiowumumuo Hammmmuwz Hahnmosmz mmHoomw Aomuwo mmoomuommmv one Ha%noonoz Hahsaouoz Hflmnmouofiz one no Hamnoouomz Haunoouooa umnaoz memogm momueao seam a“ mm>eoa mo oueusouuom .uuewwea .m smaem ha venomous mums scans mmuoaw muofiuuoa cued ecu mo omosu undone housewouono vosmfiflnoe scum “cause ago ma some mums mandamuommma Had .mmHOHu unease vow huoauuoa .uoooomumuo vmuomaom mo mommmflo muwm mama on» aw mm>mm~ mo mommummoumq_%o acmw&wqasu V .% QNQ£~ Ms A nit.“ ate: ('7 SYSTEMATIC PALEOBOTANY Description and a discussion of each of the ecologically important non-angiospermous plants follows. They are grouped in alphabetical order within the broad categories of ferns and gymnosperms. The systematics of the Cretaceous and early Tertiary angiospermous plants has been recently reevaluated (Dilcher, 1974). In the past nearly 150 years, most fossil angiosperms, particularly dicotyledons, have been referred either directly or indirectly, to extant genera. But; as Dilcher (1973, 1974) has shown, several other extant taxa might Juat as well have been chosen for reference to the fossils. For eRample, in the Eocene, Puryear, Tennessee flora described by Berry (1916a, 1924, 1930b, 1941) a majority of the dicotyledons have been 8 1Ven modern generic names or are described as being probably related or at least similar. Dilcher (1974) now has evidence that at least 602 of these generic names have been incorrectly applied to the fossils. If this is true for the Eocene, then it must be true for the much older IJ'Pper Cretaceous floras. To compound the problem, leaf morphology of elitant plants, including secondary, tertiary, and fine venation and eI’lldermal cells, is only now being studied in a way which would allow the discovery of probable consistent patterns within groups such as faIllilies or genera (Dilcher, 1974; Hickey, 1973). Therefore, at the I):"~‘esent time, and until much more work is done with living plant leaves, f"arther comparison of fossil dicotyledons to extant genera seems futile. 141 232i: I l 2. rd. 1‘ s e1 ' {it I 142 Because of the unsettled condition of the systematic position and. nomenclatureof fossil angiosperm leaves, they have been omitted from the descriptions of the fossil plants here, with the exception of the palm, Geommites imperialis . Asp Zenium dicksonianum Heer (Plate 3, Figure 2) AspZenium dicksonianum, Newberry, 1895, p. 39, pl. 1, figs. 6, 7; pl. 2’ £188. 1-8; p10 3’ figs 30 Description of the Blackhawk specimens: Several poorly preserved fragments of this fern were collected at The incomplete pinnules vary from 1 cm the Water Hollow site, 8/24/70. Total size and shape long and 0.3 cm wide to 4 cm long and 1 cm wide. 0f the complete fronds is unknown. The ultimate pinnules are lanceolate and attached to a thin, foliate rachis. The margin is entire to shallowly lobed and appears to be thickened or perhaps slightly revolute at the margin. A single midvein can be seen in each ultimate pinnule, but secondary venation is entirely obscure. The foliage of this plant aearns to have been somewhat thin but coriaceous and heavily cutinized. NeWberry (1895, p. 40) used the term "polished" to describe the leaf anIt'face, indicating its thick cuticle. No cuticle with epidermal cell impressions could be obtained from the Blackhawk fossils. Because of its obscure venation and lack of color contrast with the rock matrix this specimen was difficult to photograph. Thus the drawing was prepared. As shown, there are few features to characterize the plant. Therefore, its relationship to other Cretaceous ferns and u 1‘ ”u-av ‘ l..t..l~ I:.. it. h .5.» 1‘ 0 a ‘ ’0. p, '1‘ r” 1 pg. U H Iv; 5.; H 5‘. 5. he.‘ a . 4. 143 to the living species of Asplemlum may be questioned. Fern fragments similar to these were collected in abundance in the Amboy Clays of Woodbridge, New Jersey (Newberry, 1895). Assznium dicksonianum was a member of the swamp plant community and, as explained earlier, seems to have been an epiphyte on the conifer Sequoia cuneata . cyathea pinnata (MacGinitie) LaMotte (Plate 3, Figure l) Cyathea pinnata, LaMotte, 1952, p. 140; Pabst, 1968, p. 36, pl. 2, 3, 4’ Se Hem-italic: pinnate, MacGinitie, 1941, p. 97, pl. 10, £13. 1. Description of the Blackhawk specimens: Complete fronds of this fern have not been collected in Blackhawk Sediments but fragments consist of an unbranched axis 3 to 7 cm long. These axes are most likely the secondary or tertiary pinnules of a much la‘rger frond. They are covered with small, alternate or opposite, “1 timate pinnules, 0.7 to 1.7 cm in length which vary in shape from deltoid to linear. All are inclined or curved such that their apices point to the anterior (proximal) end of the axis to which they are a“:tached. A few pinnules are narrowly attached to the rachis but most a‘t‘ebroadly attached (decurrent) and some are even joined to one another at their bases because of an incomplete cleft between pinnules. The apax of most pinnules is acute, but a few are rounded. The venation 1‘1 the ultimate pinnules consists of a central midrib which extends Ileaxly to the apex. The open, dichotomous secondary veins diverge :W‘ DRE ..43 w 3’. "‘7’ U'U.‘l sped: I I’- .eI‘, a u,‘ 1‘9 rv H- 144 from the midrib at an acute angle and curve toward the margins. They are not decurrent. Some veins are unbranched, others are once-branched, and a few are twice-branched; none have three orders of branching. These veins do not anastomose. A few veins in the base of some of the ultimate pinnules arise directly from the main rachis rather than from the midrib of the pinnules. Fertile specimens have not been collected in the Blackhawk Forma- tion. This Cretaceous collection apparently represents the earliest Occurrence of this plant, but it seems indistinguishable from Tertiary 8Decimens found in the middle Eocene Ione Formation (7) (MacGinitie, It is 1941), and the Paleocene Chuckanut Formation (Pabst, 1968). also much like CZadophZebis fisheri collected in the Lower Cretaceous I(OOtanie Series (Knowlton, 1907). This fossil species is thought to be related to species in the eJ'Ztant genus of "tree ferns", Cyathea. This plant was discussed as an apparent member of the herbaceous understory of a Blackhawk swamp. Onoclea hebridica (7) (Forbes) Bell (Plate 4, Figures 1, 2) Onoclea hebridica, Bell, 1949, p. 40, pl. 20, fig. 5; pl. 24, fig. 3, 5; Pl. 25, £13. 2. D38 cription of the Blackhawk specimens: Fragments of this species consist of small axes 4 to 10 cm long, Probably 15 cm or more long when complete, with opposite or alternate ultimate pinnules. They are obovate to spatulate in outline and 145 appear to be the complete frond of this species. The ultimate pinnules are linear to ovate with margins which are broadly crenate to coarsely serrate. Venation consists of a broad, 2 mm wide, midvein in both the main and secondary axes which is characterized by a parallel striation on either side. In some specimens it appears that these lateral and parallel striations are secondary veins while in other specimens they look like ridges or channels in the mesophyll. All the major midribs in the pinnules including those which extend into some of the lobes of the ultimate pinnules have these striations. The fine venation is evident in only one specimen, but it is apparent that the veins branch and anastomose, forming numerous, small aerola, about 2 mm long and 0.5 mm wide, before they reach the margin. Fertile fronds have not been collected in the Blackhawk Formation. This fern seems to range into the Paleocene where it has been collected by Bell (1949). He considered his species to be conspecific with those of Onoclea sensibilis fbssilis collected by Newberry (1898) in the Fort Union Formation. Newberry considered his specimens to be very much like the living sensitive fern 0. sensibilis but the diag- nostic fertile fronds of this fossil plant have not yet been collected. Two small fragments of a fern of similar appearance, Wbodwardia crenata have been collected by Knowlton (1900) (1917) and Dorf (1942) in Cretaceous sediments. However, all fragments are too small to characterize or to compare adequately with the Blackhawk specimens. In the Blackhawk Formation, this species was collected chiefly in swamp sediments. At one locality, 7/11/70 II, it was found preserved ;a H 'I’ 146 in growth position, apparently buried as it grew on the surface of peaty swamp soil. Osmunda hOZZicki Knowlton (Plate 3, Figure 6) Osmunda hollicki, Knowlton, 1917, p. 246, p. 30, fig. 6. Sphenopteris hoZZicki, Bell, 1957, p. 23, pl. 4, figs. 1, 5. Description of the Blackhawk specimens: Complete fronds of this fern have not been reported in any Cretaceous flora, but the Blackhawk specimens indicate that they were bipinnate, probably broadly ovate in shape, 3 dm or more in length and 1.5 dm broad. Apparently, only the apical portions of the compound fronds have been collected during this study, but these specimens indicate that there were at least 3 secondary and probably 5 to 7 secondary pinna on the complete frond. These pinna (which are that portion of the plant most often collected) are borne suboppositely along the main rachis and are in turn divided into 8 to 15 ultimate pinnules. The ultimate pinnules are lanceolate to oblong in shape and range from 1 to 3 cm long. They are borne alternately along the secondary rachis. Margins of the ultimate pinnules are deeply lobed near the base, undulate in the mid portion and entire near the apex. The apex is rounded. The open, dichotomous venation of the ultimate pinnules consists of a distinct midvein which extends to near the apex, and secondary veins which diverge from the midvein at an acute angle. They are slightly decurrent to the midvein. The secondary veins are typically forked 1 to 4 times as they extend to the margin. Seause I :5 his 5; the syst 4 Elalihav p HM e :“her I lift-ace . F 'n. a! In“: i the e 1° the “usual traZSpc or551212 147 They do not anastomose. No fertile fronds have been collected in the Blackhawk or other formations. Bell, 1957, says specimens collected from Vancouver Island are undoubtedly the same species that Knowlton (1917b) collected from Colorado and New Mexico, but places them in the.form genus Sphenqpteris. Because he gives no justification for this and because illustrations of his specimens do not show critical details, it is best to leave the systematics of this plant as Knowlton established them. The Blackhawk specimens are apparently only the third collection of this species reported to date. It ranges from the Campanian to the Maestrichtian. As indicated earlier in this report, Osmunda hOZZicki seemed to prefer bottomland habitats where it apparently made up most of the herbaceous understory. Chaney (1925) infers that any fern foliage which is commonly found as fossils probably was very abundant in the living forest. Unknown Fern 1 (Plate 3, Figures 3,4,5) Description of the Blackhawk specimens: The specimens collected in the Blackhawk Formation consist of three equal sized pinnules attached in palmate, trifoliate organization to the end of a 2 cm long rachis. Five specimens clearly show this unusual type of pinnule arrangement, suggesting that it is not the transport-damaged condition of a single specimen, but was the actual organization of at least a portion of the frond. Individual pinnules .V'UMU Saul: . 1 “I. {0' | ICE Pa. ‘ .5.“ .n n we 9‘2. s~t 148 range in size from 1.5 to 3.5 cm in length and from 1.3 to 1.8 cm wide. They are oval to slightly ovate in shape with obtuse bases and broadly rounded apicies. The margin is entire to slightly undulate and is marked by a distinct, dark, vein-like line which could be the remains of a marginal vein, marginal sclerenchyma tissue, a slightly revolute margin or immature marginal sporangia. The midvein is distinct and extends nearly to the apex of the pinnule. Secondary veins are not decurrent to the midvein, but diverge at an acute angle and run parallel to one another to the margins. They are open and dichotomous, branching at least once, typically near the midvein, but commonly branching again midway or near the margin. Discussion: Associated with all the trifoliate specimens and many isolated pinnules is a thin, longitudinally striated stem, 1.5 to 3 mm wide. In three of the complete specimens it passes directly through or near the axis of the trifoliate organization. Because no other plant remains are directly associated with these fern fronds, and because of the interesting symmetry of these stems to the pinnules, this may have been the main rachis of a much larger compound leaf or it may have been the thin stem of a climbing fern. This fern is very similar to two other Cretaceous ferns previously described, AspZenium occidentale (Knowlton, 1917b, p. 84, pl. 31, figs. 2-5; Brown, 1933, p. 3, pl. 1, fig. 5) and Pteris? sp. (Knowlton, 1917a, p. 245, pl. 30, fig. 3). It is similar to several species of the living genus PeZZea, which have marginal sporangia. It also bears 149 a superficial resemblance to certain large-leafed clover species, particularly Trifblium amoenum, T. flavulum and T. repens. This species seems to have been restricted to bottomland environ- ments where it was part of the herbaceous understory. Araucarites sp. (Plate 4, Figures 4 to 8) Araucarites, Presl. 1838, p. 204 (in Sternberg, 1838) Description of the Blackhawk specimens: Many leafy twigs of this plant have been collected in sandy, apparently point bar sediment, at 3 localities. These specimens have been preserved as casts of the stems and leaves, often with a carbon- aceous residue remaining inside. Most are the apical areas of thin twigs, l'to 3 mm in diameter, but a few are of older, thicker stems, 2 cm wide. All specimens are fairly short, the longest being 11 cm, and none are branched. Leaves are narrowly awl-shaped, 1.5 to 2 cm long, and recurved toward the stem apex. All have an accuminate apex: and a slightly expanded base, 1 to 2 mm broad. Some leaves, particu- larly on older, larger twigs are slightly decurrent. The leaves remain attached even as the stem increases in circumference, but the leaves do not increase much in lateral dimension, as do those in certain living evergreen conifers. This has the effect of moving individual leaves apart from one another or making them less dense on older twigs. Stomatal bands, other epidermal features and venation have not been preserved. 150 In some specimens the rock matrix has broken at right angles to an embedded twig revealing the appearance of the twigs in cross section. In all cases, the leaves are equally distributed around the circum- ference of the twig in a "bottle-brush" fashion. It seems possible to imbed and cut one of these specimens in serial section and thus determine its phyllotaxy. This has not yet been done. Several rhombohedral to triangular shaped cone scales, similar to those Dorf (1942) considered to have belonged to foliage he called Araucarites Zongifblia, were collected in the Blackhawk Formation. However, since none of the specimens were collected in association with the foliage, and since all scales were collected in several swamp, rather than point bar localities, it is unreasonable to believe they are part of the same plant. Although I consider the Blackhawk species to be much like the foliage of extant species of the genus Araucaria, there is no other basis for believing it to be related. Several plants have similar foliage including species in the extant genera cryptomeria, Cunninghamia, Dammara, GZyptostrobus, Juniperus, and Sequoiadendron, plus extinct species in the genera Cunninghamites, Elatidés, Geinitzia, and Sequoia. Perhaps with more efforts directed toward the determina- tion of phylotaxy and epidermal features, a better estimate of its true relationship to living plants can be made. Many other large Upper Cretaceous floras illustrate foliage which is similar in appearance. However, there remains a considerable amount of confusion in the nomenclature and systematics of this foliage even though the first specimens were collected more than a century ago. 151 Some of the plants which look very similar to the Blackhawk are the following: Araucarites Zongifblia (Bell, 1965, p. 24, pl. 11, fig. 8) Damnara sp. (Knowlton, 1922, p. 114, pl. 2, fig. 4) EZatocZadus albertaensis (Bell, 1965, p. 16, pl. 7, fig. 4) Geinitzia formosa (Newberry, 1895, p. 51, pl. 9, fig. 9; Knowlton, 1900, p. 28, pl. 5, figs. 1, 2; Knowlton, 1917b, p. 251, pl. 31, figs. 1-3; Bell, 1965, p. 14, pl. 6, fig. 5) Sequoia acuminata (Lesquereux, 1878, p. 80, pl. 7, figs. 15-16a; Knowlton, 1922, p. 114, pl. 2, figs. 7-8) Sequoia bifbrmis (Ward, 1885, pl. 31, figs. 7, 8) Sequoia Zongifblia (Lesquereux, 1878, p. 79, pl. 7, figs. 14, 14a; pl. 61, figs. 28, 29) Sequoia reiohenbachi (Berry, 1903, p. 59, pl. 48, figs. 14, 20; Hollick, 1906, p. 42, pl. 3, figs. 4, 5) The Blackhawk specimens have leaves which are generally shorter and much thinner than the variable-sized leaves of: Araucarites Zongifolia (Dorf, 1942, p. 130, pl. 4, figs. 9, 12, 13; pl. 5, figs. 1-6) Cunninghamites ? sp. (Knowlton, 1900, p. 29, pl. 5, fig. 3) Sequoia Zongifolia (Knowlton, 1922, p. 115, pl. 3, fig. 3; pl. 4, fig. 2) EZatocZadus was proposed as a comprehensive form genus for sterile coniferous shoots that cannot otherwise satisfactorily be assigned to other groups of plants or when it is undesirable to imply relationship 152 to other plants (Arnold, 1942). It may be best to eventually include the Blackhawk araucarites-like foliage in this form genus, as Bell (1965) has done. This plant may have been a member of the piedmont community above the Blackhawk floodplain. Brachyphyllum macrocarpum Newberry (Plate 4, Figure 9; Plate 5, Figure 1) BrachyphyZZum crassicaule, Fontaine, 1889, p. 211, pl. 100, fig. 4; pl. 109, fig. 1-7; pl. 110, figs. 1-3; pl. 111, figs. 6, 7; pl. 112, figs. 6-8; pl. 158, fig. 9; Brown, 1950, p. 50, pl. 9, fig. 5, 6. Braohyphyllum crassum, Lesquereux, 1892, p. 32, pl. 2, fig. 5; Newberry, 1896, p. 51 (see his footnote), pl. 7, figs. l,2,5,7. Brachyphyllum macrocarpum, Newberry, 1895, p. 51, p1. figs. 1-7; Knowlton, 1900, p. 29, pl. 4, figs. 5, 6; Hollick, 1904, p. 406, pl. 70, figs. 4, 5; Berry, 1905, p. 44, pl. 2, fig. 9; Berry, 1906, p. 168, pl. 9; Hollick, 1906, p. 44, pl. 3, figs. 9, 10; Hollick & Jeffrey, 1906, p. 200; Berry, 1910, p. 420; Berry, 1910, p. 183; Berry, 1912, p. 392, pl. 30; Berry, 1912, p. 106; Berry, 1914, p. 106; Berry, 1914, p. 21, pl. 3, fig. 2; Knowlton, 1917b, p. 249, pl. 31, fig. 4; Berry, 1919, p. 59, pl. 5, fig. 9; Berry, 1922, p. 160, pl. 36, fig. 1; MacNeal, 1958, p. 54. Thuites crassus, Lesquereux, 1883, p. 32. Description of the Blackhawk specimens: The Blackhawk specimens are composed of the leafy, much-branched 153 portions of woody stems. They vary in width from 2.3 cm to about 0.3 to 0.5 cm in the youngest branches. The youngest branches range from 1 to 4 cm in length. All branches are subopposite and distichously arranged. The ultimate branchlets were apparently pendulous and flattened, forming frond-like horizontal sprays. The largest axis collected is 19 cm long, 15 cm wide, has 4 orders of branching, and at least 10 flat sprays or branchlets. It was used as the basis for the reconstruction. The accuracy of the reconstruction was improved by examining all 155 Blackhawk specimens and included aspects of stem size, branching pattern, branch shape, number of branches, leaf size, leaf shape and leaf markings. Not indicated in the reconstruction is the range in size of the lateral branchlets, representing the latest season's growth. One such specimen, with only 1 order of branching, was 18 cm in length and 3.5 cm in width, about twice the size of those illustrated in the reconstruction. The stems are covered with spirally arranged scale-like, rhome boidal leaves which range in width from less than 1 mm on the youngest stems to about 5.5 mm on the oldest. They are appressed to the stem along the whole adaxial surface. On older leaves there are numerous thin ridges which radiate from the apex toward the base. Most leaves have small, 0.01 mm diameter, irregularly spaced glands near the base. Stomatal bands or other epidermal features could not be determined. No cones or other reproductive structures of this plant were collected in the Blackhawk Formation. Many Blackhawk specimens exhibited an interesting transition from the typically poorly preserved youngest branches with obscure or 154 indistinct leaf patterns to the better preserved lower or older portions where the leaves were very well defined. Almost all the above listed workers either comment on the poor preservation of the ultimate branches of their specimens, or illustrate this with drawings or photographs. A reasonable explanation of this observation is that the living plant produced succulent or very soft branch and leaf tissue the first year, but as the branches aged and thus increased in girth, the leaves also grew in width and breadth producing much more scleren- Chymous tissue. This is not unusual and can be observed in existing genera such as cupressus, Juniperus, Sequoiadendron, and others. This development of leaf and stem hardness is probably also related to the growth and branching pattern of the plant. After examining many specimens, it appears that the youngest stems have a determinate growth pattern which allows them to reach a limited size with a certain number of leaves. These branches remain small (1-2 cm in length) the first season but begin increasing in length and diameter the second or perhaps third season when they also produce lateral stems. This explains the difference in the size of the leaves and stems and is in keeping with the typical long shoot-Spur shoot growth pattern of many living conifers. Brachyphyllum is chiefly a genus of Jurassic and Lower Cretaceous plants although several Upper Cretaceous species have been described. However, methods for distinguishing them have not been clearly estab- lished (Brown, 1950). B. macrocarpum seems to be the only species remaining through the Santonian and Campanian, and it seems to have become extinct in the Maestrichtian. 155 Plants in the genus BrachyphyZZum are known to have been among those which produced the common Mesozoic pollen genus CZassopoZZis spp., although gymnosperms of other types were also probably involved (Chaloner, 1969). The numerous species of this plant have not been critically examined since Berry's (1911, 1914) work 50 years ago. This genus could be reexamined with recent knowledge of new collections, the stratigraphic and geographic range of the apparent palynomorphs, its Mesozoic origin and distribution as it was affected by continental movements and its ecological requirements examined in this report. No anatomical studies have been done on petrifactions of wood or cones since near the turn of the century (Hollick and Jeffery, 1906; Jeffery, 1906) and these studies might also need reevaluation or commentary. The Blackhawk specimens were restricted to swampy environments, where apparent clusters of trees were only of local importance. It is thought that these swamps were entirely fluvial floodplain in origin, some distance from the coastal strand. One small florule collected in probable brackish water sediments on the delta had no specimens of Brachyphyllum, suggesting that it was restricted by brackish water. All other North American collections in which it is possible to deter- mine rock matrix type indicate that this species was collected in clay (Newberry, 1896; Hollick, 1906; Berry, 1914a, 1914b) or black clay (Brown, 1950) also suggesting swampy or quiet-water environments. Wieland (1916) misidentified several specimens of a Jurassic (Liassic) species of Brachyphyllum in Mexico when he considered several 156 leafy twigs to be the remains of a cycad Williamsonia sp. He apparently thought that the rhomboidal leaves were leaf base scars of the much larger compound cycad leaves which were found in associated rocks. However, these specimens seem to be unquestionable branching stems of a species much like those of B. macrocarpum, including such features as leaf size, arrangement, and vertical striations.(Wieland, 1916, pl. 4, fig. 1; pl. 33, figs. 1, 2, 4; pl. 34, figs. 1-5; pl. 35, figs. 1-3; pl. 36, fig. 4 in part). Moriconia cyclotoxon Debey and Ettingshausen (Plate 6, Figures 3,4; Plate 7, Figure 1) Mbriconia cyclotoxon, Debey and Ettingshausen, 1859, p. 59, 64, pl. 7, figs. 23-27; Heer, 1882, p. 49, pl. 33, figs. l-9b; Heer, 1883, p. 53, fig. 10; Newberry, 1895, p. 55, pl. 10, figs. 11-22; Hollick, 1898, p. 57, pl. 3, fig. 10; Hollick, 1907, p. 46, pl. 3, figs. 16, 17; Berry, 1903, p. 65, pl. 48, figs. 1-4; Berry, 1911, p. 86, pl. 8, figs. 3—6; Berry, 1925, p. 30, pl. 3, figs. 1, 2 Pecopteris kudZisentensis, Heer, 1874, p. 97, pl. 26, fig. 18. Description of the Blackhawk specimens: The specimens of this plant are leaf covered, decussate, branch- lets which formed flattened sprays similar to those of several extant species in the family Cupressaceae, particularly Libocedrus spp. They consist of a flattened central axis with numerous decussate secondary or ultimate branches. The outline of the entire branchlet is distinctly wedge shaped, widest at the base and tapering toward the apex. They 157 range in size from specimens 1-2 cm wide and 6 cm long to those which are 4 cm wide and 20 cm long. The apex of most branchlets is acuminate, the base being acute to obtuse and typically forming a thin, flattened petiole-like structure 3 mm wide and 5 mm long. The secondary or ultimate branches are 1 to 3 cm in length, lanceolate in shape with an acute to round apex, broadly attached to the main axis at the base. All are inclined at about a 45° angle toward the apex. The leaves are scale-like and closely appressed to the stems. Two kinds are evident, those which occur over the midrib areas of the main axis and ultimate branches. These are dorsal-ventrally flattened, have broadly attached bases and broad, semicircular apicies. Most of them are slightly keeled. The second type of leaves occur lateral to the first, in opposite pairs on the margins of the main and ultimate branches. They are narrower than the other leaves and are compressed transversely (or laterally) over the edges of the main and secondary stems. They have acute apicies but broad bases. Ultimate branches arise in axes of the lateral leaves on the main stem. Both types of leaves become smaller toward the apex of the branches. These branchlets appear to have been deciduous units. This possibility has been men— tioned by Berry (1914). The main vascular strand is 1-2 mm wide at the base. In some specimens a vein can be seen to diverge from the main strand and enter an ultimate branch. Leaves show no veins. A single Blackhawk specimen is apparently a fertile branch, with a small single staminate strobilus sunken in the acute apex of the ultimate branches. These are carbonized and spherical in shape, 0.5 to 0.75 mm in diameter. No structure or organization was preserved 158 such as scales, bracts or sporangia. Significantly these are the first strobili described (Berry, 1925). They are very similar in size, shape and position to the stament strobili of certain members of the family Cupressaceae, and support the proposal that Mbriconia was a member of that family (Berry, 1925). A single strobulus was carefully chipped from the rock matrix in which it was imbedded and macerated in standard polynologic methods for analysis of fossil palynomorphs (Cross, 1968). It was hoped that possible Mbrioonia pollen could be isolated and thus characterized, but the strobili yielded numerous trilete spores and angiosperm pollen grains. Apparently all the pollen the plant produced had been shed, leaving an empty cone as a potential trap for wind blown polynomorphs of other types. Cross (personal communication, 1973) said that entrap- ment of foreign pollen and spores in empty cones and anthers is fairly common in extant plants. In general outline the flattened sprays of Mbriconia spp. have the appearance of a once-pinnate fern frond with narrow, pointed pinna. The first European and Greenland specimens were considered ferns of the genus Peoopteris and it was not known to be a coniferophyte until much later (Berry, 1925). Berry (1925) has discussed the stratigraphic and geographic dis- tribution of Mbriconia spp. At that time he considered it one of the "most characteristic fossil plants" in stratigraphic determinations of strata of Cenomanian to Santonian age. The Blackhawk specimens there- fore increase the geologic range into the Campanian and the distribution into Western North America. ‘2'" l‘ I ... ..- 'Q ‘C D f- " le. 92: ti: \h‘ 159 Two species of Mbriconia have been previously described,.M. cyclotoxon and MK americana. Berry, 1925, says that they are probably the same biological species but because Mk americana differs in size and stratigraphic distribution, he suggests that they remain as separate forms. References to this second species are: Berry, 1910, p. 20, 186; Berry, 1914, p. 26, pl. 7, figs. 1-4; Berry, 1916, p. 802, pl. 56, fig. 1; Berry, 1925, p. 31, pl. 3, figs. 3, 4. Mbriconia cyclotoxon seems to have been a common plant of the floodplain and brackish delta swamps of the Blackhawk coastal strand. Other specimens of the genus were also collected in swamp or coastal strand sediments (Berry, 1914, 1925) and suggest that this plant was a consistent member of fresh water and brackish water swamp communities. Nageiopsis sp. (Plate 6, Figures l,2,5,8) Nageiopsis, Fontaine, 1889, p. 194. Description of the Blackhawk specimens: Thirteen leafy twigs and more than 1,000 isolated leaves of an apparently new species of Nageiopsis were collected at site 8/19/70 at Pipe Springs. Individual leaves are typically cuneate, but range from suborbicular to lanceolate in shape. They also vary in size from leaves 5 mm long and 4 mm wide to 24 mm long and 6 mm wide. The apex of all specimens is acute and the base is always round. Margins are entire. Venation consists of 10 unbranching, parallel veins of equal thickness which diverge at the base and converge at the apex. No major midvein is present. All leaves were thin, but seem to have 160 been sclerified or rigid. Attachment to the twigs is distichous and opposite, by a short, decurrent petiole up to 1.5 mm long. Leaves. occur only on ultimate twigs which appear to be the latest season's growth. Older stems have no leaves, suggesting, with the abundance of isolated leaves in the sediment, that the plant was annually deciduous. Ultimate twigs, which are up to 7 cm long, thin and uncurving, and have the appearance of also being erect. Branches also arise in opposite, distichous pairs. A single specimen exhibits 3 orders of branching, while the other twigs show only 2 orders of branching or were ultimate twigs. Twigs typically exhibit leaf scars consisting of the decurrent petiole bases; these scars are less evident on the larger twigs. One twig 5 mm in diameter was collected. Although the Blackhawk specimens represent only the terminal branches of the plant, the short ultimate branches and the opposite or often dichotomous branching pattern suggest that the entire plant was probably shrub-like in appearance. Because all the specimens of Nageiopsis sp. were collected within a 10 cm thick horizon in a single block which was .75 m wide and l m long, it seems probable that they were produced by a single plant. The presence of Nageiopsis in this study is significant because it has heretofore been considered an exclusively Lower Cretaceous genus. It was originally described by Fontaine (1889) from the Lower Cretaceous (no younger than Albian) Potomiac series of Virginia. Fontaine (1889) so named this group of plants because of their close resemblance to living plants of the Nageia section (tribe?) of the genus Podocarpus. 161 The true relationship of these plants to any members of the Podocarpaceae has been questioned by Berry (1910) and Arnold (1947). Arnold (1947) reported that no fructifications of this plant had been collected. However, several fragments of small, apparently staminate conifer cones were observed in the rock matrix of the Nageiopsis site (8/19/70). One of these was removed and macerated according to standard palynological techniques (Cross, 1968). Several hundred pollen grains were isolated, supporting the thought that it had indeed been the remains of a staminate cone. Cross (personal communication, 1972) tentatively identified the pollen as being similar to some of the earlier "Podocarpus types." These cones and pollen grains, although not showing organic connection to the foliage of the Blackhawk Nageiopsis sp., may have been produced by it. Nageiopsis sp. was collected in sediment of swamp origin and because of the numerous leaflets collected, unquestionably grew in the immediate vicinity. Podozamites sp . (Plate 6, Figures 6,7) Podozamites (Brongniart) Braun, 1843, p. 28 (in Munster, 1843) Description of the Blackhawk specimens: Fragments and a few complete specimens of this plant were collected in several Blackhawk sites. They are elongate, linear-lanceolate to ovate in outline with entire margins and range in size from specimens which are 0.7 cm wide and 4 cm long to those which are 1 cm wide and 8 cm long. The base is acute with a short petiole; the apex is 162 typically acute but in some specimens it is slightly rounded. No midvein is present in these specimens; all veins are of equal size, are parallel with one another and are straight and unbranched. They do not converge at the tip, but gradually st0p as they are encroached upon the narrowing margins. None of the specimens were attached to a stem or rachis and no epidermal or other cellular features could be determined. No repro- ductive structure was collected in association with these specimens which could be considered part of this plant. The Podozamites fossils found in the Blackhawk strata may be derived from two or more species. Those found at the bottomland sites, 7/30/70 and 8/25/70, were much smaller and more oval than those col- lected in the swamp sites, 8/14/70, 8/18/70, and 8/19/70. Many species of Podbzamites have been described from Europe, Russia, and North America in rocks ranging from Triassic (Daugherty, 1941) to the lower Tertiary (Brown, 1962). The genus was originally proposed for leaves believed to belong to cycadophytes because the leaves, when attached to a rachis, are similar in appearance to a pinnate cycad frond. Later it was observed that the supposed pinnae of some species are spirally arranged on the twigs, indicating that it is a leafy shoot. In addition, the leaves of some species seem to have been deciduous (Arnold, 1947) and are often found detached like those of the Blackhawk flora. 163 Protophyllocladus polymorpha (Lesq.) Berry (Plate 6, Figures 9,10; Plate 8, Figures 3,5) Adiantites praelongus, Dawson, 1893, p. 25, pl. 5, fig. 19; Dawson, 1894, p. 55, pl. 6, fig. 6. Proteoidea major, Dawson, 1893, p. 61. pl. 12, fig. 54. P. obesus, Hollick, 1930. P. polymorpha, Lesquereux, 1895, p. 362; Berry, 1903, p. 438-445; Bell, 1957, p. 35, pl. 19, fig. 5; pl. 20, figs. 1, 2, 4; pl. 21, figs. 1, 3, 5; pl. 25, fig. 4; Bell, 1963, p. 31, pl. 9, fig. 5. P. subintegrifolius, Lesquereux, 1874, pl. 1, fig. 12; Lesquereux, 1892, pl. 2, figs. 1-5; Hollick, 1906, p. 36, pl. 5, figs. 1-6; MacNeal, 1958, p. 51, pl. 31, fig. 3. Salisburia baynesiana, Dawson, 1883, p. 25, pl. 5, fig. 21. S. polymorpha (nomen nudum), Lesquereux, 1895, p. 362. Thinfeldia Zesquereuxiana, Heer, 1882, pl. 46, figs. 1-126; pl. 49, figs. 9, 10. T. montana, Knowlton, 1900, p. 11, pl. 1, figs. 1-3. Description of the Blackhawk specimens: Several complete phyllodes (phylloclades) of this plant have been collected in the Blackhawk Formation ranging in size of from 6 to 15 cm long, and from 1.5 to 7 cm broad. Fragments of some specimens suggest that they were often nearly twice that size. They are generally obovate in outline but are variable and include oblanceolate, spatulate, and obcordate forms. The apex is typically acute or round but in some it is emarginate or otherwise deeply cleft. This apical cleft is often l MN on ) .l .5...“ “to“ ‘1'; ul.l::£ 7?": NE a 'Yn' '1' 164 as deep as 1/3 the length of the leaf, giving these specimens an appearance similar to the leaves of the extant Ginkgo biloba. The base is attenuate or wedge shaped, forming a thick, 0.5 cm wide, petiole-like structure often 1-2 cm long, where it attaches to the plant. Margins, are also variable including forms which are entire, undulate, irregularly lobed, and irregularly cleft or divided to the midrib. In some specimens the lobing is similar to that of Protophyllocladus Zobatus (Berry, 1914, pl. 2, figs. 9-13) only the individual lobes are broader and less frequent than those of that species. Occasional small, 0.5 mm long, teeth have been observed on a few specimens. When present, the teeth are either located at the apex of small lobes or are irregularly spaced, at least 2 mm apart, along otherwise entire margins. The main axis of each phyllode has a more or less distinct midvein or vascular system which is typically the width of the "petiole" at the base of the phyllode, becoming less and less distinct toward the apex. Judging from the vertical depth of the impression it usually formed in the rock matrix, this midrib was 2 to 3 mm thick in life. The lateral veins or vascular bundles diverge at an acute angle to the midrib and curve to the margin. They remain parallel with one another but may or may not bifurcate once or rarely twice. They never anastomose. These lateral veins are numerous and lie close to one another with roughly 20 to 25 veins per cm, similar to the veins in Ginkgo biloba leaves. The phyllodes of this plant are simple, and often crowded together at the tip of small, 0.5 cm wide branches. The thickness of the carbonaceous remains of certain specimens was nearly 1 mm thick, suggesting that 165 they were very thick structures, probably coriaceous in life. No cuticular remains could be isolated from the Blackhawk phyllodes. As pointed out earlier in this report, Protophyllocladus polymorpha preferred swampy or otherwise saturated floodplain soils and was an abundant member of the fluvial swamp community. It is not found in a small florule collected in the apparent brackish waters of the Blackhawk delta. It-seems to have been evergreen. This plant is abundant in several floras of both North America and Europe where it has been known for more than a century. It apparently ranges from the Albian through the Maestrichtian and into the Paleocene; however, it is interesting that it is absent in several major Upper Cretaceous floras. Undoubtedly, its geographical distribution was, strongly controlled by environmental factors. More specimens have been collected in the Blackhawk Formation (124 specimens) than in any other flora, perhaps suggesting that it was entirely restricted to fresh water conditions similar to those of the Blackhawk floodplain. It probably is related to the living genus PhyZZocZadus (Podo- carpaceae) with at least 7 species which are all currently restricted to the Southern Hemisphere. Other species of this genus have been collected in Cretaceous and Early Tertiary strata, but problems still exist in the systematics of Protophyllocladus spp. and Thinfeldia spp. which should be resolved before the limits of this genus can be defined. 166 Protophyllocladus sp. 2 (Plate 8, Figure 2) Description of the Blackhawk specimens: The collection site 7/28/70 II at the Taylor Flat locality yielded nearly 50 phyllodes of an obvious member of the genus Protophyllocladus. They were generally similar to those of P. polymorpha, but differ enough to isolate them from that species, at least until all the possible ecotypes of P. polymorpha are known. Earlier, in the dis- cussion of the stratigraphy of Taylor Flat, it was mentioned that these odd specimens may have been produced and shed from one P. polymorpha tree which was in poor health because of burial of the trunk base by overbank sediment. Phylloclades of this plant are typically much wider than those of P. polymorpha, and are very broadly obovate. At least one specimen (7/78/70 11, 22-41) is reniform in outline with a crenate to serrate anterior margin, measuring 5 cm long and 5 cm broad. It is very unlike the wedge-shaped phylloclades of the P. polymorpha. These specimens also differ in having much shorter "petioles", fewer marginal lobes and an apparent membranous texture rather than being thicker or coriaceous. About 8 very small, 0.5 cm wide and 0.5 cm long, apparently immature phyllodes were among those collected at this site. Since they are the only immature phyllodes of any species collected, they may support the proposal of being shed from a dying tree, perhaps early in a growing season. 167 Sequoia cuneata Newberry (Plate 8, Fig. 4; Plate 9, Figs. l—l3; Plate 10, Fig. 1; Plate 11, Fig. 4) Foliage: Metaaequoia cuneata, Chaney, 1950, p. 229, pl. 11, figs. 1-6; Bell, 1957, p. 31, pl. 11, figs. 3, 5, 6; pl. 13, fig. 2; pl. 17, figs. 1, 7; Bell, 1963, p. 29, fig. 1, only. Sequoia affinia, Parker, 1968, p. 27, pl. 2, figs. 4-7. sequoia brevifblia, Lesquereux, 1874, U. S. Geol. Survey Terr., Ann. Rept., p. 298 (no illustrations); Lesquereux, 1878, U. S. Geol. Survey Terr., vol. 7, p. 78, pl. 61, figs. 25-27; Knowlton, 1900, U. S. Geol. Survey Bull. 163, p. 27, pl. 4, figs. 1-4. Sequoia cuneata, Newberry, 1898, U. S. Geol. Survey Mono. 35, p. 18, pl. 14, figs. 3, 4a. Sequoia dakotensis, Brown, 1939, U.S. Geol. Survey Prof. Paper 189, p. 247, pl. 48, fig. 10; Dorf, 1942, Carnegie Inst. Wash. Pub. 508, 129, pl. 6, fig. 4-6 (not figs. 8-11 as Chaney, 1950, believed). Sequoia heterophylla 7, Knowlton, 1905, U. S. Geol. Survey Bull. 257, p. 132, pl. 16, fig. 5. Sequoia Zangdorfi, Lesquereux, 1878, U. S. Geol. Survey Terr., vol. 7, p. 76. Sequoia macroZepis 7, Heer, 1883, vol. 7, p. 16, pl. 51, fig. 13. Sequoia nordenskioldi, Dorf, 1938, Carnegie Inst. Wash. Pub. 508, p. 45, pl. 1, fig. 10. Sequoia obovata, Knowlton, 1916, p. 333; Knowlton, 1917, p. 250, pl. 30, 168 fig. 7; Hollick, 1930, p. 58, pl. 25, figs. lO-12; pl. 29, fig. 2b; Capps, 1940, p. 201. Sequoia wincheZZi, Lesquereux, 1895, p. 10, p1. A, fig. 1. sequoiites sp. cf. Gainitzia fbrmosa, Bell, 1963, p. 28, pl. 12, fig. 4. Tamodium cuneatum, Newberry, 1863, Boston Jour. Nat. Hist., vol. 7, p. 517; Dawson, 1893, Roy. Soc. Can. Trans., vol. 1, p. 25. Tumion 7 suspeotum, Hollick, 1930, p. 55, pl. 19, figs. 4-6a; pl. 29, fig. 16. Cones: Geinitzie fbnmosa, Bell, 1963, p. 28, pl. 12, figs. 2, 3, 4 only (note that fig. 2 shows foliar attachment). Sequoia graciZZima, Berry, 1903, p. 57, pl. 48, figs. 21, 22; Newberry, 1895’ p. 50, p19 9’ £188. 1.3. Description of the Blackhawk specimens: This conifer, one of the most abundant plants collected in the Blackhawk flora, has been described by Chaney (1950). Although he considered this plant to be a species of Metasequoia, analysis of foliage, epidermal cells, and reproductive structures of the Blackhawk specimens indicate that it clearly falls within the description of the genus Sequoia. Information to support this conclusion will be subse- quently presented, as will other aspects of morphology which are either new or are modifications of Cheney's (1950) descriptions. The reconstruction of the leafy axis with staminate and pistillate cones, was based upon the specimen, 8/24/70, Ol3A-020A. All aspects 169 of twig, leaf, and cone gross morphology were considered; however, the staminate cones were added. Cheney's (1950) description of the foliage is as follows: Foliage shoots bearing monoporphic, acicular leaves except at base where they are scaly; of two types, long. shoots which are persistent and develop into branches, and short shoots which are deciduous. Long shoots bearing needles up to 14 mm.long (some probably longer, but incom- plete), and up to 3 mm. broad; needles decussately attached and rotated into flat sprays prior to the development of short shoots in their axils, at which stage they show a return toward diametrically opposed position, and become widely spaced as the shoot lengthens and short shoots develop; subtending needles commonly deciduous during or after shoot development; needles in whose axils no short shoots have developed may be persistent, including single needles on one side of the stem where a shoot has failed to develop or has been shed. Short shoots slender, straight or curving, up to 5 cm. long, bearing at maturity 15 to 20 closely spaced pairs of leaves, decussately attached but always rotated into distichous position, longest in lower half of shoot, and progressively shorter to its apex; commonly shed separately. Leaves typically slender- oblanceolate, abruptly rounded at the base, and narrowed to a very short petiole, much widened and rounded at apex with a mucronate tip which is seldom preserved, or more rarely of uniform breadth to apex; approximate average dimensions at middle of shoot 8 mm. by 1.8 mm.; closely spaced on shoot, branching off at angles under 90 degrees but seldom as low as 45 degrees; obliquely attached on decurrent bases which are fairly prominent and extend obliquely down shoot to next pair of needles; needles somewhat more persistent than those of.M. oocidentaZis; midvein well defined. Because moretfiuu1450 leafy twigs of S. cuneata were collected in the Blackhawk Formation, several modifications can be made to Chaney's description. First, short shoots, more than twice as long as those he described, up to 12 cm in length with at least 96 leaves, are in the Blackhawk collection. Typically, they are shorter with fewer leaves, 5 to 8 cm being average length. Second, the short shoots were not deciduous. More than one half of the specimens, 257, were long shoots. 170 The rest, 212 specimens, were isolated short shoots, some of which may have shown attachment to long shoots if the rock matrix had been excavated. Thus, the total number of long shoots was probably higher. This, therefore, does not support Cheney's suggestion that the plant was deciduous. Instead, it seems to have been an evergreen species which lost foliage because of external factors such as wind or animals. All the foliage of S. cuneata which was collected is apparently mature, rather than immature, and was therefore shed from the plant sometime after spring growth ended. The shoots and growth of this fossil plant can be described in terms of short shoot-long shoot organization, similar to many extant and extinct conifers. The short shoots typically became long shoots after the first season by an increased length and thickness. As this transition occurred, the short shoot leaves lose their distichous organization and become more spiral. They also become more obviously decurrent, and are moved away from one another. Although the foliage of this plant is generally like that of the living redwood, S. sempervirens, periodic growth or overdwintering features are not evident in the fossil plant as they are in the living redwood. S. sempervirens has obvious clusters of small, spirally arranged, awl-shaped leaves typically at the base of short shoots. These are the slightly enlarged and hardened protective leaves which enclosed the bud during the non-growing season. No such over-wintering bud scales or buds can be observed on any of the Blackhawk specimens. In this aspect, the fossil S. cuneata is more like Sequoiadendron gigantea which does not typically display overdwintering features or buds. 171 Older twigs, up to 1 cm thick, which Chaney (1950) did not describe have now been collected. They clearly show leaf scars. Cuticular fragments were isolated from needle-like leaves of two specimens using the preparation techniques of Dilcher (1963). They are described below according to the format and terminology suggested by Dilcher (1974). Besides having impressions of numerous epidermal cells one specimen had remains of 3 stoma. The epidermal cells are short-rectangular to isodiametric in shape and arranged in indistinct rows parallel with the long axis of the leaf. Most have square end walls; a few end walls are oblique. Neither the lateral or end walls have undulations or ornamentations. The stomatal complex is oriented with the long axis of the guard cells parallel with the long axis of the epidermal cells and leaf. Their position and organization on the leaf is unknown. The guard cells were apparently sunken, their impressions on the cuticle was not preserved. Subsidiary cells were tetracytic. See Plate 11, Figure 4. Both staminate and pistillate cones were collected in the Blackhawk flora, some attached to foliage. The 2 staminate cones apparently had deciduous scales and seem to be incomplete. They are ovoid, 8 mm long and 4 mm wide, attached to the end of a leafy shoot. Cone scales are not clearly seen, but seem to have subtended the 8 or 10 globose sporangia, very similar in appearance to male cones of S. sempervirens. One cone was chipped from the rock matrix and macerated, using standard palynological techniques (Cross, 1968), but unfortunately no Taxo» diaceous pollen could be isolated. 172 About 30 pistillate cones are in the Blackhawk collection, seven of them attached to foliage shoots of S. cuneata. They are narrowly oval to rectangular in shape and thus differ from the subglobose cones of S. sempervirena. They range from mature specimens 4 cm long and 1.2 cm wide to those which are 7.2 cm long and 1.8 cm wide. Fifteen to 20 scales may be seen in the fossil compressions, suggesting that 30 to 40 scales were present in complete cones. Scales are peltate with a hexagonal outer face, 4 to 5 mm tall and 7 mm wide. An umbo, 2 to 3 mm wide, which is in the center of each scale, terminates in a thin, erect spine about 0.5 mm long. Most scales showed shallow striations radiating outward from the umbo to near the margin. A narrow, 1 mm wide, rim is present around the hexagonal periphery. One cone had been preserved whole without distortion in the rock matrix and had subsequently been broken to allow a transverse view. It shows 5 scales attached to the axis in an apparent spiral fashion and is definitely not cruciform in organization as cones of Metasequoia. When mature all the scales presumably fit tightly together, but separated or shrank apart in dehiscence. This seed dispersal mechanism is similar to the living redwood and several other species in the families Taxodiaceae and Cupressaceae. Pistillate cones were borne on the end of a thick, 3-4 mm wide, leafy twig. One incomplete twig was 4.5 cm long and bore at least 15 awl-shaped leaves. Six small ovulate cones in the flora are apparently immature. All were 2.4 cm or less in length, had exactly the same number of scales as the larger or mature cones, and were attached to the ends of leafy S. cuneata twigs. None of the scales have the thickened ‘l and 5:1 tirecti were 6.: late a have t :equir requir E: g. plan: of th likel 5PM 173 and sclerified appearance of those of mature cones. Because all were directly associated with mature rather than immature foliage, they were dropped from the tree sometime after spring growth, perhaps as late as the end of the first growing season when strong winds could have torn them from the plant. This may suggest that two seasons were required for their maturity. Although the living S. sempervirens requires only one season for cone maturity, the closely related Sequoiadendron gigantia does require two. Chaney (1950) supposed that certain Cretaceous pistillate cones which Dorf (1942) and Hollick (1930) collected were produced by this plant. However, all of them were attached to naked stalks. In light of the Blackhawk cone morphology and stem attachment it does not seem likely that these specimens belonged to S. cuneata. A single Sequoia-like seed was recovered. It is 4 mm wide and 6 mm long with a wing or membrane which partially surrounds the embryo. Although it was not connected directly to a cone scale it is less than 0.5 cm away from the fragment of a seed cone and 0.5 cm away from a leafy twig of S. cuneata. It is nearly twice the size of seeds of S. sempervirens and Sequoiadendron gigantea, but is remarkably similar to them. It is thought that it is a seed of S. cuneata. This fossil plant falls within the limits of the genus Sequoia as it has been defined and discussed by Buchhotz (1938, 1939), Chaney (1950) and Bierhorst (1971). Although it has at least 4 features similar to Sequoiadendron it seems clear that it is not a.Metasequoia as Chaney (1950) believed after he examined a limited number of leafy specimens. The following indicate its relationship to the genus Sequoia: 174 1. Leaves of short shoots are subopposite or alternate rather than opposite as in Metasequoia. 2. Leaves are borne spirally and secondarily rotated into a distichous position whereas in Metaaequoia leaves are borne distichously. 3. Branching is always alternate, never Opposite as in Metasequoia. 4. Short shoots are normally persistent not deciduous as in Meta- sequoia. 5. Two types of leaves are present, needle-like and awl-like, whereas Metasequoia (and Sequoiadendron) produce only one leaf type.. 6. Epidermal cell shapes, and stomatal orientation are like those of sequoia (and Sequoiadendron)and are clearly unlike Metasequoia. 7. The peltate pistillate cone scales are Sequoia-like in general appearance. They resemble no other Taxodiaceous genera. 8. Staminate and pistillate cone stalks are covered with leaves like S. sempervirens, and are not naked like those of Metasequoia. 9. Cone scales are attached to the axis in a spiral manner, not cruciform or decussate as in Metasequoia. The features of this plant which are somewhat similar to Sequoia- dendron are: l. The awl-like leaves present on the pistillate cone stalks. 2. The epidermal cell size which is normally smaller than in Sequoia sempervirens. 3. The lack of overdwintering bud scales and buds. 4. The apparent two-year period for pistillate cone development. Recently, Eckenwalder (1976) has proposed that the families Taxodiaceae and Cupressaceae be combined because of numerous 175 similarities which make them closely related. The recovery of S. cuneata with such obvious Sequoia-like features indicates that any divergence of the two families occurred much earlier than the Upper Cretaceous. The foliage of S. cuneata has been collected widely in Western and Central North America during the last century. Localities include those in Alaska (Hollick, 1930); Fort St. John, Alberta (or perhaps‘ British Columbia, it is unclear) (Bell, 1963); Kootenai, British Columbia (Dawson, 1893); Namaino, British Columbia (Newberry, 1863, 1898); Vancouver, British Columbia (Bell, 1957); Craig, Colorado (Dorf, 1938); Vermejo, Colorado and New Mexico (Knowlton, 1917b); Austin, Minnesota (Lesquereux, 1895); Marmarth, North Dakota (Brown, 1939); Fruitland, New Mexico (Knowlton, 1916); Black Buttes, wyoming (Lesquereux, 1878); Lance Creek, wyoming (Dorf, 1942); Point of Rocks, Wyoming (Lesquereux, 1874, 1878; Knowlton, 1900); and Judith River, state unknown (Knowlton, 1905). All are apparently Santonian to Lower Maestrichtian in age. The foliage of this plant seems to have been rare in all the localities. Although it has been called many different specific names, almost all authors have recognized its Taxodiaceous affinities. The distinctive ovulate cones have also been widely collected. These range from an unidentified locality in Alberta (Bell, 1963); a single site at Vancouver, B. C. (Newberry, 1898) and three sites entirely disjunct from.western cone and foliage sites in New Jersey. They are near Cliffwood (Berry, 1903; Jeffery, 1911) and Key Port (Newberry, 1895). It is interesting that while only six cones had 176 previously been collected in the west, not counting those of the Blackhawk Formation, apparently hundreds were collected in New Jersey. The western cones including most of the Blackhawk specimens are com- pressions, while those in the east are preserved whole as lignified remains or are petrified.. Jeffery (1911) examined the cellular structure of several petrified specimens. No S. cuneata foliage was collected in association with the New Jersey specimens. Only 2 of the previously collected cones showed attachment to foliage twigs (Bell, 1963, pl. 12, fig. 2; Newberry, 1895, pl. 9, fig. 2), the rest were found unattached to twigs of any type. The significance of the leafy cone stalks as a means of distinguishing genera of Taxodiaceous plants had not been recognized in the reports of these previously collected cones. The disjunct distribution of the cones, which were on either side of the Cretaceous epicontinental sea, suggests the possibility that at least 2 species existed which produced cones of similar appearance. Considering this and the large number of fossil species which have been referred to the family Taxodiaceae in the last 150 years, a major monograph of the family is probably in order. Although Chaney (1950) made significant contributions to certain Taxodiaceous genera, the systematics may be more complex than he has indicated. S. cuneata clearly preferred the Blackhawk fluvial swamps where it was an apparent co-dominant tree. Several aspects of this plant, discussed earlier, indicate that it was an approximate ecological equivalent to the living bald cypress, Taxodium distiohum of south- eastern North America. 177 Widdringtonites reichii (Ettingshausen) Heer (Plate 8, Figures 1,6) Widdringtonites reiohii, Heer, 1882, p. 51, pl. 28, fig. 5; Berry, 1914, p. 25, pl. 2, figs. 14—17; Berry, 1916, p. 793, pl. 55, fig. 1; Newberry, 1895, p. 57, pl. 10, figs. 2-4; Bell, 1963, p. 30, pl. 12, fig. 1, pl. 13, figs. 1,4. Description of the Blackhawk specimens: The specimens collected in the Blackhawk formation consist of the terminal portions of several much-branched axes. The largest specimen is 22 cm long, consisting of a main stem with numerous, alternate branches; three orders of branching are evident. The secondary branches arise on all sides of the main stem and thus do not form distichous, flattened sprays as in Mbriconia spp. and BrachyphyZZum spp. The main stem is about 16 cm long and 2.5 mm wide at the base. Smaller, ultimate branches are 0.5 cm to 4.5 cm long and very narrow, typically about 0.5 mm wide. The leaves are broadly awl-like to ovate, spirally arranged on the stem but very small, no longer than 1 to 2 mm. On ultimate branches where they are clearly observable, there are usually 6 to 8 leaves per cm. They are apparently much more appressed to older stems or are missing altogether. No cones or other reproductive structures have been collected in the Blackhawk Formation. Both microsporangiate and megasporangiate cones have been col- lected in other Cretaceous collections in Europe, Greenland and North America. They are very similar to extant species of the genus Widdringtonia and, based upon both foliar and reproductive morphology, 178 they have been referred to that extant genus (Berry, 1925). Two species of the fossil genus.Widdringtonites have been collected, the. other being W. subtilis also of Europe, Greenland and North America (Berry, 1914). They are very similar in appearance. The stratigraphic range of this species seems to be Cenomanian to Campanian. Its occurrence in the Blackhawk Formation is only the second time it has been collected in Westeranorth America (Bell, 1963). W. reichii appears to have been an infrequent or relatively unimportant member of the Blackhawk fluvial swamp communities. Geonomites imperiaZis (Dawson) Bell (Plate 11, Figures 1 to 3) Geonomites imperialis, Bell, 1957, p. 37, pl. 22, fig. 5; pl. 23, fig. 2; pl. 24, fig. 3. Description of the Blackhawk specimens: No complete leaves of this species have been collected in any Cretaceous flora, however, by piecing together several large Blackhawk fragments, it is now known that they are 2 m or more.in length and about 0.5 to 0.8 m wide. The leaves are simple, pinnate, and oblong to oblong-obovate. The apex is rounded in outline and the base is acute to slightly attenuate. The blade was at least 1.0 to 1.5 m in length and attached to the end of a 0.5 to 0.8 m long petiole. The leaf blades are plicate or folded into lamina or rays, typical of all palms. These plications are reduplicate or A-shaped in cross-section 'with the midrib prominent on the upperside, characteristic of most extant pinnate genera (palmate genera with some exceptions are 179 induplicate) (Corner, 1966). The orientation of these plications in the fossil palms is therefore a convenient means of determining the. adaxial or abaxial surface of these leaves as they are preserved in the rock. Each ray or fold is about 8 to 25 mm broad and are united by their edges except near the leaf margins where they normally split apart. Each contains about 5 to 10 parallel veins, 0.3 to 0.8 mm apart with 3 or 4 intermediate striae between and parallel with them. The rays diverge from the rachis at broad angles from the base of the blade, while near the center of the blade they diverge at about 30° and near the apex they diverge at 10 to 15°. These plicae normally are decurrent to the rachis for l to 2 cm. The margins of all the leaves examined is made of the distal splitting of the plicae to a distance of from 15 to 30 cm toward the rachis. These splits only reach the rachis in the most weathered or perhaps transport-damaged specimens. The major portion of the blade of these leaves is therefore solid, and not divided or split into leaflets. The rachis extends from the petiole to near the apex of the blade. At the base of the blade it is about 3 cm wide and tapers gradually to near the apex where it is only a few mm wide. It is longitudinally striated. The petiole is unarmed. Throughout most of its length it is 3 to 6 cm wide, but widens abruptly at the base into a wedge-shaped structure, 17 to 20 cm broad. This expanded portion attaches to the stem as a decurrent, short sheath. In situ trunk casts (described on p. 69) had several of these wedge-shaped petiole bases attached to them. Both the petiole and the widened base are also longitudinally striated. The depth of 180 the.impressions of a few leaf fragments indicate that the petiole at the base of the blade was 1 to 2 cm thick. Apparently based upon incomplete specimens, Brown (1962) con- sidered Geonomites imperialis and several other species to be of the genus SabaZ, a group of palmate or fan—leaved palms. However, the large specimens (although also incomplete) collected in the Blackhawk Formation clearly indicate that this species has a rachis which extends throughout the length of the blade making it pinnate in organization. One such specimen was recovered from Unit 0 at the Water Hollow locality. It is composed of a 0.6 m long petiole with the wedge-shaped base and a portion of the leaf blade. The petiole extends into the blade as a gradually tapering rachis, rather than the abruptly tapering or wedge-shaped rachis (hastula) of the fan palms. On the same rock slab several leaf apicies are present and clearly show the narrow, tapering rachis near the apex. In addition, the rays of this plant are clearly decurrent, leaving little doubt that this species is a pinnate rather than a palmate palm. A group of these palms described earlier in this report (p. 69) were growing on a peaty substrate of a Water Hollow swamp as close as 1.5 to 2 m to one another. Since the leaves were longer than the distance between the trunks, a tight palm thicket must have been formed. In other localities, isolated leaves were recovered in coarser bottomland and point bar sediments, but all the leaf "mats" were associated with swamps. This suggests that although many plants extended into adjacent environments, they grew most abundantly in swamps or near swamp margins. :ig. l flcra spec: that ' 181 ..The restoration of Geonomites visianii by Berry (1914, p. 38, fig. 4) is.somewhat similar to that of G. imperiaZis in the Blackhawk flora, except I have reason to believe that the leaves of the Blackhawk specimens remained attached to the base of the plants after they died, that the leaves occurred much closer together, vertically, along the stem, and that the leaf margins were normally split at the plications. Recently, Read and Hickey (1972) have proposed a classification of Mesozoic and Cenozoic palm foliage. They emphasize that because it is very difficult to identify specimens of modern palms accurately from leaves alone, attempts to place fossil palm fragments in genera of modern palms probably gives a confused picture of the floristics of the geologic record. For example, leaves of the extant genera Geonoma and Manicaria are almost impossible to distinguish without seeing flowers or fruit. It is therefore questionable that the fossil Geonomites imperialis bears any relationship to the extant genus Geonoma, and only has a superficial foliar resemblance to it. Perhaps, as Read and Hickey (1972) suggest, fossil leaves of this species should be placed in the form genus Phoenicites A. Brongniart. This species seems to have been restricted to sediments of Campanian age. APPENDICES :‘ete: l by, ‘If uUbub mile in 0:1 last 01'! bel: Se: CD 41. Set on 182 APPENDIX I COLLECTION LOCALITIES Several areas in the Wasatch Plateau were examined in order to determine the most feasible collection localities. Fossil plants were found at a large number of places but only six were selected for major collection. All six localities are within 200 yards (180 m) of either Utah State Highway 29 in Straight Canyon, west of Orangeville, Utah, or Interstate 70 in Salina Canyon, east of Salina, Utah (Figure 1). Most localities include three or more specific plant-bearing horizons or sites. These localities and sites are identified and described below. 1. Cox Swale collection locality in Straight Canyon is in SW 1/4 sec. 2, T. 17 S, R. 6 E and in the adjacent NW 1/4 sec. 11, T. 17 S, R. 6 E, Hiawatha, Utah Quadrangle. It is in a road cut on the north side of Utah State Highway 29, opposite and northwest of Cox Swale, about 300 yards (275 m). It is 14.2 miles (22.9 km) from Orangeville, Utah. One site was excavated in the above road cut, 7/11/70 II. A second site, 7/11/70 I, was excavated approximately 200 meters west on Utah 29 in a small amphitheatre-like wash (see Figure 4). 2. Black Diamond Mine collection locality in Straight Canyon is in NW 1/4 sec. 12, T. 17 S, R. 6 E, Hiawatha, Utah Quadrangle. It is southwest of the abandoned mine entrances about 200 yards (180 m), and on the east-facing slope of the small amphitheatre-like canyon. This 183 locality is 12.9 miles (20.8 km) west from Orangeville, Utah and 1.4 miles (2.3 km) east of the Cox Swale locality. Collection sites excavated here were: 7/23/70 1, 8/28/70 1, 8/28/70 II, 8/28/70 III (See Figure 4). 3. Knight Mine collection locality in Salina Canyon is in SW 1/4 sec. 34, T. 23 S, R. 4 E, Acord Lakes, Utah Quadrangle. The collection sites here are adjacent to the abandoned mine road about 50 yards (45 m) west and below the mine entrance. This locality is 31.0 miles (50 km) from Salina, Utah,on Utah State Highway 10 (being replaced by Interstate 70). Collection sites excavated here were: 7/22/70, 8/26/70 1, 8/26/70 11, 8/26/70 III (see Figure 4). 4. Taylor Flat collection locality in Salina Canyon is in NW 1/4 sec. 21, T. 22 S, R. 6 E, Water Hollow Ridge, Utah,Quadrangle. It is 30 yards (27 m) north of Interstate 70 at the point where the highway enters (from the west) the down-faulted graben at Taylor Flat. It is 18.6 miles (29.9 km) from Salina, Utah. The sites excavated here were: 7/8/70 I(l), 7/12/70, 7/18/70 I(l), 7/28/70 I(2), 7/28/70 1(5), 7/28/70 11, 7/30/70 1, 7/30/70 II, 7/30/70 III (see Figure 4). This is at the same position as that section measured by Spieker and Baker (1928). 5. Pipe Springs collection locality in Salina Canyon is in NW 1/4 sec. 20, T. 22 S, R. 3 E, Water Hollow Ridge, Utah,Quadrangle. It is 200 yards (180 m) north of Interstate 70 in a small unnamed canyon, herein called Pipe Springs Canyon. (Before the construction 0f Interstate 70, there existed a roadside water fountain, piped out 184 of this canyon from a small spring.) This locality is 17.5 miles (28.2 km) east of Salina, Utah. The collection sites are 165 feet (50.3 m) above the canyon floor. The sites excavated here were: 6/1/68, 7/9/70 I(l), 7/9/70 I(2), 7/9/70 1(3), 7/17/70 I(l), 7/18/70 I(2), 8/13/70, 8/14/70, 8/15/70, 8/18/70, 8/19/70, 8/20/70 (see Figure 4). Collection number 6/1/68 was collected entirely by W. D. Tidwell. This is the same section measured by Bachman (1958) and Baughman (1958). 6. Water Hollow collection locality in Salina Canyon is in NE 1/4 sec. 14, T. 22 S, R. 2 E, Steve's Mountain, Utah,Quadrangle. It is about 200 yards (180 m) northwest of where Interstate 70 crosses Salina Creek on a steep east-facing slope. Most of the collection sites were under the massive, overhanging sandstone, about 170 feet (52 m) above the road. It is 13.3 miles (21.4 km) east of Salina, Utah. Sites excavated here were: 8/24/70, 8/25/70, 8/29/70, "Base of Road Cut", "Unit 1", "Unit K", "Unit M", "Railroad cut" and "Above railroad cut" (see Figure 4). In addition, several fragments of Araucarites sp. were collected in a large sandstone block which had been exposed in the construction of Interstate 70 about 2 miles east of the Taylor Flat locality. This site was termed "Road Construction." Its stratigraphic position is unknown, although it is probably within the middle 1/3 of the Blackhawk Formation. 185 APPENDIX II OTHER FOSSIL LEAF IMPORTANCE INDEX CONSIDERATIONS A second fossil plant Importance Index could be constructed to consider the large number of fossil leaves which were unidentifiable. Table 1 shows that of the dicotyledons collected, 2071 could be identi- fied and 2928 were not identifiable out of the 4999 dicot leaves differentiated in the collection. This total is 2.4 times more than those actually identified. An Importance Index might be as follows: Fossil Leaf a Relative frequency + 2.4 Relative density Importance Index of dicots of dicots The index for the non-dicotyledonous plants would be calculated as in the Fossil Leaf Importance Index used earlier. The results of this calculation are interesting and are listed in Table 10, where they are compared with the Importance Index obtained using the first formula. It is my opinion that this index gives a more realistic idea of the true relationship among dominant plants in the living community, since it uses the total number of dicot leaves collected, instead of those that are identified. At least one problem in using this third index is that the unidentifiable dicot remains might be from species other than those which are identified. However, it is my own opinion that if there are taxa which as yet have not been recognized among the dicotyledons, they are unimportant members of the communities statistically. 186 It is thought that because of the bias in various factors of preservation, a fossil species which is represented by a few specimens in a majority of collection sites is ecologically more significant than a species which might be found in great abundance at only one or few localities (R. Anstey, personal communication, 1972). Therefore, consideration has been given for the construction of a third possible Fossil Leaf Importance Index in which "frequency" is used instead of "relative frequency." Frequency is determined as follows: Fossil Plant a number of collection sites in which the species occurred Frequency number of collection sites x 100 This third Fossil Plant Importance Index using frequency could be calculated as follows: Fossil Plant Importance Index = Frequency + Relative Density When this is used for the 43 important Blackhawk species, the plants are listed in almost exactly the same order as when the first Importance Index (using Relative Frequency and Relative Density) is used. Unfortunately, none of these Importance Indicies can be compared directly to Importance Indicies calculated from plants in living communities. A method to determine the number of individual plants in the Blackhawk communities has not been found and probably will have to await the completion of studies correlating the number of leaves on the forest floor with the number of parent plants in several types of living communities. 187 Table 10. A comparison of the values from the two Importance Indices. Taxa Swamps Bottomlands Point Bars I.I. I.I I.I. I.I. I.I. I.I. #1 #2 #1 #2 #1 #2 Asplenium dicksonianum 1.8 1.8 0 0 0 0 cyathea pinnata 3.2 3.2 O O O O Onoclea hebridica 3.4 3.4 1.1 1.1 0 o Osmunda hoZZicki 2.4 2.4 6.9 6.9 O 0 Unknown Fern l O 0 1.7 1.7 0 0 Arauearites sp. 0 O 0 O 31.6 31.6 Brachyphyllum macrocarpum 13.8 13.8 0 0 O 0 Mbriconia cyclotoxon 6.4 6.4 1.0 1.0 O 0 Nageiopsis sp. 1.4 1.4 O O O 0 Podozamites sp. 3.5 3.5 O 0 47.9 47.9 Protophyllocladus polymorpha 15.0 15.0 6.0 6.0 11.4 11.4 Protophyllocladus sp. 2 0 0 5.4 5.4 O O Sequoia cuneata 43.4 43.4 7.1 7.1 7.7 7.7 Widdringtonites reichii 1.5 1.5 0 0 0 0 cyperacites sp. 4.1 4.1 1.2 1.2 O 0 Geonomites imperialis 9.2 9.2 4.3 4.3 15.9 15.9 Anona robusta 1.4 2.4 O O 0 0 Apocynophyllum giganteum 3.1 3.5 4.3 6.4 O 0 Cereidiphyllum arcticum 1.2 1.9 27.3 60.3 9.5 13.4 Cissus marginata 7.0 11.9 9.2 13.0 4.3 5.7 Cbrnus denverensis 3.9 5.4 2.5 3.3 O O Cbrnus praeimpressa 4.1 6.9 5.7 7.2 3.6 4.0 Dryophyllum subfalcatum 5.5 7.3 19.0 35.2 13.3 22.5 Dryophyllum whitmani O O 3.9 6.7 O O Ficus Zaurophylla 2.7 3.5 3.1 3.5 0 O Ficus planicostata 2.1 3.1 2.1 2.4 5.0 7.4 Laurophyllum coloradensis 0 0 7.5 12.8 0 0 Manihotitea georgiana 2.4 2.8 7.4 13.8 3.5 4.0 Menispermum dauricumoides O O 2.5 3.3 4.0 5.0 Myrtophyllum torreyi 4.7 6.4 9.4 16.1 0 0 PhyZZites vermejoensis 3-2 4-7 7.3 11.1 0 0 Platanus alata 1.9 2.6 3.1 4.8 O O Platanus raynoldsii 10.8 18.1 21.2 36.6 16.1 20.0 Rhamnites eminens 18.1 31.7 4.7 6.1 9.1 12.5 Salix gardneri 2.4 3.8 1.3 1.9 O 0 Salix proteaefblia 2.8 3.8 O O O O salix stantoni 0.8 0.9 3.7 5.0 O O Viburnum antiguum 2.3 2.6 3.7 6.2 3.6 4.0 Unknown Dicot 2 O 0 13.4 29.5 I O 0 Unknown Dicot 13 3.7 6.9 2.2 2.6 , o 0 Unknown Dicot 19 1.9 2.6 1.0 1.1 ‘ 13.0 21.8 Unknown Dicot 25 2.8 5.7 O O . O 0 Unknown Dicot 32 1.5 2.6 o o . o o ms? I ‘F—A“ E 0.! J. i . 188 APPENDIX III RAINFALL CALCULATIONS Calculations to determine the total precipitation in the drainage basin of the Cretaceous Ferron River described by Cotter (1971). 6,500 ft3/sec for 11 months 22,000 ft3/sec for 1 month Total 7,000 sq miles - 1.95 x 1011 2.45 x 1011 £c3 1.95 x 1011 ft = 1.25 feet 15" = 20% of Precipitation 15 .20. Precipitation 75" (190 cm) s Precipitation - 1.88 x 1011 ft3 10 t3 = 5.70 x 10 f l - 2.45 x 101 ft3/year ft2 - 15" runoff 189 APPENDIX IV DICOTYLEDONS IN EACH OF THE FLOODPLAIN ENVIRONMENTS o H H H H «3:84.32... .3855. N.. N N m «H m N N N 3H H NH 3 N 2 ..H Hm a HH HH H NN 33.28 83:65. H.. o o H H .nu TC §Hau§§m 0.. _ o o N H. .2688: nausea». an . o H H o nHoHnann anHznnn mm 1 o N N o 3833?: meugmmmosenm R m H H .. N meH a m H Nm 2 N NH 0 N a H: H H. H a m a N a ”.8383: 3883 on o NH 2 N N H N 8an 3.3%... an o NH «H N NH m m NH H N NH nanrnnnnnnnn mmnHHHmem an o c m N H T833 omumNHnHHm mm o e s o nennwmnuno nnHHNHNen NH 9 w H H o nHHnennnnnn uncensnnnnmn Hm o _ o H H engages senescensae on o .sn NH m N N N mH H N H H o annexes stHsenonnNz AN N N . o m H o mmmmosaowtaom Eastuumwrez N H H _ .... on o «N .. H H N 332an snununimnz N o _. e s N N announce inHHNennHHormnz oN H H m o N N H N N nHHpiHensn nHHnenn: mN c w o o 0 Eggs soamrmmoawe ..N o N N a a means 53HH3enntnsN MN o m. mN oH NH N o nennnnnnann :nNHNenonnsH NN o o N c H 3398m€3u ESE HN o m o N H H mwoeertenumom 383 ON A m . N H N HH 0 N nunnmnnanan magma aH o . .H N H H H. .H H .H nHHénnnéH ennui 3 o _ o e H H N anxnnnnnHm manna NH 0 o .. .H censuses exmsk 3 o nN 0N H o assesses anHmennmuq HH 2 H 3 00H n ..m on a m H H .H 3 N H H H m NH EzeooHuedam Esififihog ..H o H H H H sesame guacamesoe NH H H 3 N H N m H Om mH m 0H cemetefimoau @3589 NH 0 o n q 0H N N m N mmmrmaemrmfi N358... HH N H _ mm o .N H H H N H Nm H o H H H. enuresis: masses OH 0 c m 6 unevenness Exfiogrrmo o o o N N ExemmEmur... £3526:er m m n m mg m T. NcH 3H d m Exomnoao ExmmemummToLem N o o m w Eauouxmrx 533095633 0 o H H o Emuoumfio EJHmemgumonb m o N N H H mmmaerfloaoo ExHmeuotoHowuNeb a c N m o .NH n H N H H Exeerommm Exmumxuormoouw m o o o o ramosuwto .32.. N o 0 0H 0H senses.» motor“. H N 9 8 8 I. I. IH 9 9 9 9 I. I. I. I. I. I. I. I. I. 0 n n 9 3 9 8 8 8 9 8 I. I. I. I. I. I. 9 m o w I I I I / 0 q I I l I l l I l l l I I l m u u u I I I I l , / I I I l I I / / nwmnnnnuunuuuummmuuummn unuunmamnnuuummnun 53 see... I "I. I I i I I a, l I I l I. I. l w I I I I I l I I I I l I I I 9 o l 0 0 0 O 0 0 0 0 0 0 0 0 0 0 0 0 O 0 O 0 O 0 O 0 O 0 O 0 O H. a m 1 n I. 3 I... when uchHH mvcoH-Houuon mnaazm .mueosaouH>ao :HsHevoOHm emu mo some cH moovlouoan .HH oHnma (con't) Table 11. 190 Point Bars TVLOL uoraonaasuoo pron 3‘0 'I 'I 'AOQV III II I I'I 01/9Z/8 Ot/9Z/8 Ol/9Z/9 OLIZZ/L OL/lt/L COOOO0OHOOOOCOO02HOOOOOOONOOOOOOOOOOOOOO 12 r-l N Bottomlands TVLOL 3“3 P'OX II'H III II III II H I HH I 0L/6Z/8 0L/8Z/8 01/82/8 01/92/8 OL/OC/L Ol/Of/L 0L/OCIL Ol/SZIL OLICZ/l Ol/II/l C-I Ol/GIL Z'I 0L/6/l 1'1 0L/8/L ..g MN N H N CH P“ H N ...b‘? .\ tr. Swamps I TVIOI H ltufl X 37““ I 31"“ Ol/SZ/S 0L/9Z/8 OLIOZ/S Ol/6I/8 OI/SI/S Ol/SI/B OL/VI/S Ol/EI/B OL/BZ/l I Ol/BZ/L I Ol/SIIL Ol/SI/L OLIZI/L OL/II/L 89/I/9 v-lNHHHOfinooflmmmoog§OHNOAPIO—‘OHWONNUQH-«o n HI W H TAXA NUMBER . 51 Unknown dicotyledon 2 ............................... ............................... ............................... ............................... Salix proteaefolia Salix stantoni 47 Sapindus morriaoni 48 Trapa paulula Sal is: lancensia 49 Trapa sp. 43 Salix gardneri 50 Viburnum antiquum 44 45 46 52 53 54 55 H ‘ m-e—K“I¢‘wrhl L] I » Table 12. \OQNG-FWNH 10 11 12 13 191 A summary of the dicotyledons which appear to.he character- istic of each of the environments. to those listed in Table 11. Swamps (60 species) Texa Numbers 14(7) 29 16 30 17 33 18 34 19 35 20 36 21 39 23 40 24 41 25 42 26 43 27(7) 44(7) 45 46(7) 47 49 50 52 53 S7 58 59 62 63 65 66 68 69 71 73 74 76 77 79 80(7) 81 The taxa numbers refer Bottomlands (49 species) Tana Numbers 3 22 38 4 23 41(7) 5 26 42 7 27 43 10 28 44 11 29 46 12 31 48 13 32 50 14 34 51 15 35 53 18 36 54 19(7) 37 55 56(7) 9 59(7) 61(7) i 53 64 67 68 7o 71 72 75(7) 73 82 192 APPENDIX V PHYSIOGNOMY 0F LEAVES FROM A MICHIGAN FOREST Table 13. Leaf margins and Raunkiaer leaf size classes of the woody dicotyledons of Sanford Natural Area, Michigan State University, East Lansing, Michigan. The species have been determined by Beaman (1970) and all measurements were made by me from herbarium specimens. Entire Leaf .'"" _~ I “ta-£14.... . Taxa Margins f Size Class Acer negundo Notophyll 2 A. nigrwn Mesophyll 3 A. platcmoides Mesophyll -'-* A. rubrum Mesophyll A. saccharinum Notophyll A. saccharum Mesophyll Amelanchier Zaevia Microphyll Asirmlna triloba X Mesophyll Berbemls thunbergii X Nanophyll Carpinua caroliniana Notophyll Carya cordiformis Notophyll C. ovata Mesophyll Celastrus scandens Microphyll Ce Ztis occidentalis Notophyll Cephalcmthua occidentalis Mesophyll Camus altemifolia X Microphyll C. amomum Microphyll C. florida X Microphyll C. foemina X Microphyll C. stolonifera X Microphyll Crataegus macrospema Notophyll C. moZZis Notophyll C. punctata Microphyll C. succulenta Notophyll Dirca palustris Microphyll Euonymus atropurpureus Notophyll E. obovatus Microphyll Fagus grandifolia Notophyll Fraxinus anemicana Mesophyll F, nigra Notophyll F- quadrangulata Notophyll Gleditsia triacanthos X Nanophyll Gymnocladua dioica X MicrOphyll [1761772527772 Zia virginiama Microphyll I Z ex vertici Z Zata Microphy 11 193 APPENDIX V (Cont .) Entire Leaf Taxa (Cont.) Marlins Size Class Juglans cinema Microphyll J. nigra Microphyll Lindera benzoin X Notophyll Liriodendron tulipifera X Mesophyll Menispemwn canadenae Mesophyll Morua aZba Mesophyll M. rubra Mesophyll Ostrya virginiama Notophyll Parthenocissus quinquefolia Notophyll Platanus occidentalis Macrophyll . PopuZus deltoides Mesophyll P. grandidentata Notophyll P. tremuloides Mesophyll Prunus serotina Microphyll P. virginiama NotOphyll Ptelea trifoliata X Notophyll Quercus aZba Mesophyll Q. bicolor Mesophyll Q. macrocarpa Mesophyll Q. muhlenbergii Mesophyll Q. rubra Mesophyll Q. velutina Mesophyll Bhus typhina Microphyll Ribes cynosbati Microphyll 1?. sativwn Mesophyll Rubus allegheniensis Microphyll R. occidentalis Notophyll R. strigosus Microphyll Salix amygdaloides NotOphyll S. discolor X Microphyll S. fragilis Microphyll S. interior Microphyll S’. rigida Notophyll Sambucus canadensis Notophyll S. pubens Microphyll Sassafras albidwn X Mesophyll Staphylea trifolia Notophyll Tilia americana Mesophyll Toxicodendron radicans Notophyll T. vemix X Microphyll U Zmus americana Notophyll U. rubra Notophyll U. thomasi Mesophyll Viburnum acem’folium Notophyll V-) Zentago Mesophyll V- recognitwn Notophyll V. trilobum Microphyll Vitis riparia Mesophyll Nanophyll Z arz thoxy Zum ameri canum I'M-f ln‘lf'n‘" ~' 1 “ “"L I; . 7 7"“ We“: 194 APPENDIX VI PHYSIOGNOMY OF LEAVES IN THE BLACKHAWK FLORA Table 14. Those dicotyledons of the Blackhawk Formation which have entire margins, pinnate nervation, coriaceous texture, and drip points. The average size of the leaves in cm2 and Raunkiaer leaf size class is also indicated. When there was a possibility that the average size of the leaves could be larger if more had been measured, the leaf size class indicates a range from one class to another. a? .38. m a u u o u u-H o m a a u Efififififfiflfi 2 TAXA ngé’gysgcm Size Class 1 Anona? robusta X X 7 14 Microphyll 2 Acer cretaceum 37 Notophyll 3 Apocynophyllum giganteum X X X X 68 Mesophyll 4 Celastrophyllum carolinensis X 7 34 Notophyll S Celastrophyllum cretaceum X X 7 1 Nanophyll 6 CsZastrophyZZum undulatum X X 29+ MicrophylléMesophyll 7 Cercidiphyllum arcticum 9 MicrOphyll 8 Cinnamomum intermedium X X 7 13+ Microphyll-Notophyll 9 Cinnamomum sezannense X X X 8 Microphyll 10 Cissus marginata X 11 Microphyll 11 Cbrnus denverensis X X X 21+ Microphyll-Notophyll 12 Cornus praeimpressa X X X X 9 Microphyll-Notophyll l3 Dombeyopsis obtusa X X 24 NOtOPhyll l4 Dryophyllum subfalcatum X X X 15 Microphyll-Notophyll 15 Dryophyllum whitmani X X ? 27 Notophyll l6 Fugue cretacea X X 11 Microphyll l7 Ficus gZassconea X X X 7 60 Mesophyll 18 Ficus ZaurophyZZa X X X 7 34 Microphyll-Notophyll 19 Ficus planicostata X X X 70 Mesophyll 20 Ficus post-trinervis X 7 X 19 Microphyll 21 Ficus puryearensis X X X 7 28 Notophyll 22 Laurophyllum coloradensis X X X X 14 Microphyll 23 LaurophyZZum meeki X X X 44 Notophyll 24 Liriodéndron aZatum X X X 7 21 NotoPhY11 25 Magnolia amphifblia X X X X 40+ Notophyll-Mesophyll 26 Mbgnoliophyllum cordatum X X X X 77 Mesophyll 27 Manihotites georgiana X X 400 Macrophyll 28 Menispermum dauricumoides 30 Notophy11 29 Myrtophyllum torreyi X X 17 Microphyll 30 Nymphaeites dawsoni X 4 Microphyll 31 Pararymphaea crassifblia X X 69 Mesophyll 32 Phyllites craigensis X 7 47 Mesophyll 33 Phyllitss wilderi X X 7 28 Notephyll 34 PhyZZites vermejoensis X X X X 14 Microphyll 35 Platanus aZata X X 218 Mesophyll 195 APPENDIX VI (Cont.) a 3 0-3 3 o u a u.u o u u-a a m n a u 33:22:35 Taxa (Conn) lg 53 3." g 8 E2 a 8 cm2 Size Class 36 Platanus raynoldsii X 58+ Notophyll-Mesophyll 37 Pterospermites undulatus X X X 23 Notophyll 38 PopuZus? apicuZata X X X 26 Notephyll 39 Quercus stantoni X 7 74 Mesophyll 40 Banunculus (?) 813- X 3 Microphyll 41 Rhamnites eminens X X X X 16 Micr0phy11 42 Rhwnnus aaZicifoZius X X X 10 Microphyll 43 Salix gardneri X X X 4 Microphyll 44 Salix Zancensis X X X 6 Microphyll 45 Salix proteaefolia X X X 4 Microphyll 46 Salix stantoni X X X 11 Microphyll 47 Sapindus morrisoni‘ X X 7 12 Microphyll 48 Trapa pauZuZa 7 l Nanophyll 49 Trapa sp. 1? Microphyll 56 Viburnum antiguum X X 42 NOtOPhyll 51 Unknown dicotyledon 2 X X 12 Microphyll 52 " " 9 X X 7 20 Microphyll 53 " " 13 X X X X 33 Notophyll-Mesophyll 54 " " 14 X X 2+ Nanophyll 55 " " 15 X X 12 Microphyll 56 " " 16 X 1 Nanophyll 57 " " 17 X X X 10 Microphyll 58 " " 18 X X X 36 Notophyll 59 " " 19 X X X 7 25 Microphyll-Notophyll 6O " " 20 X X X 10 Microphyll 61 " " 24 X X 6 Microphyll 62 " " 25 X X X X 11 Microphyll 63 " " 26 X 21 Microphyll-Notophyll 64 " " 27 X X X 7 Microphyll 6S " " 30 X X X 7 8 Microphyll 66 " " 32 X X X 33 Notophyll 67 " " 33 X X X 31 Notophyll 68 " " 35 X X 7 46 Mesophyll 69 " " 36 X X 36 Mesophyll 70 " " 37 X X 15 Microphyll 71 " " 40 X X 22 Microphyll—Notophyll 72 " " 41 X X 7 21 Notophyll 73 " " 44 X X X 13 Microphyll 74 " " 46 X X 7 10 Microphyll 75 " " 47 X 7 17 Microphyll 76 " " 49 X X 7 55 Mesophyll 77 " " 50 X X 7 l Nanophyll 78 " " 53 X X X 7 1 Nanophyll 79 " " 54 X X X 7 18 Microphyll 80 " " 55 X 7 7 18 Microphyll 81 " " 56 7 7 7 70 Mesophyll 82 " " 57 X X X 2 Nanophyll $1 LIST OF REFERENCES 196 LIST OF REFERENCES Abbott, W} O. and Liscomb, R. L. 1956. Stratigraphy of the Book Cliffs in east central Utah. In: Intermountain Assoc. Petroleum Geologists 7th Ann. Field Conf., Geology and economic deposits of east central Utah: 120-123. Anderson, J. A. R. 1961. The ecology and forest types of peat swamp forests of Sarawak and Brunei in relation to their silvi- culture. Doctoral Dissert., Univ. of Edinburgh, Edinburgh. Anderson, J. A. R. 1973. The flora of the peat swamp forests of Sarawak and Brunei. Gardens Bu11., Singapore 20(2): 76-102. Andrews, H. N. and Pearsall, C. S. 1941. On the flora of the Frontier Formation of southwestern Wyoming. Ann. Mo. Bot. Armstrong, R. L. 1968. Sevier orogenic belt in Nevada and Utah. Arnold, C. A. 1947. An Introduction to Paleobotany. McGraw Hill, New York. 433 p. Arnold, C. A. and Lowther, J. S. 1955. A new Cretaceous conifer from northern Alaska. Amer. J. Bot. 42(6): 522-528. Axelrod, D. I. and Bailey, H. P. 1969. Paleotemperature analysis of Tertiary floras. Palaeogeography, Palaeoclimatol., Palaeoecol. 6: 163-195. Bachman, M. E. 1958. Geology of the Water Hollow Fault zone, Sevier and Sanpete Counties, Utah. M. S. Thesis, Ohio State Univ., Columbus. Baer, J. L. 1969. Paleoecology of cyclic sediments of the lower Green River Formation, central Utah. Brigham Young Univ. Geol. Studies 16(1): 1-95. Bailey, E. W. and Sinnot, I. W. 1915. A botanical index of Cretaceous and Tertiary climates. Science N. S. 41: 831-834. Barrett, J. W. 1962. Regional silviculture of the United States. Ronald Press, New York. 610 p. Bartram, J. G. 1937. Upper Cretaceous of the Rocky Mountain area. Amer. Assoc. Pet. Geol. Bull. 21: 899-913. “1 ..UL 197 Baughman, R. L. 1958. Geology of the Musina Graben area, Sevier and Sanpete Counties, Utah. M. S. Thesis, Ohio State Univ., Columbus. Beaman, J. H. 1970. A botanical inventory of Sanford Natural area. 2. Checklist of vascular plants. Michigan Botanist 9: 147-164. Bell, W. A. 1949. Uppermost Cretaceous and Paleocene floras of western Alberta. Geol. Survey Can. Bull. 13: 1-231. . 1957. Flora of the Upper Cretaceous Nanaimo Group of 'Vancouver Island, British Columbia. Geol. Survey Can. Memoir 293: 1-84. fl .15 . 1963. Upper Cretaceous floras of the Dunvegan, Bad Heart, and Milk River Formations of western Canada. Geol. Survey . 1965. Illustrations of Canadian fossils; Upper Cretaceous and Paleocene plants of Western Canada. Geol. Survey Can. Paper 65-35: 1-46. Berry, E. W. 19033. The flora of the Matawan Formation (Crosswick Clays). N. Y. Bot. Gard. Bull. 9(3): 45—103. . 1903b. Additions to the Matawan flora. Am. Nat. 37: 677—648. . 1904. Additions to the flora of the Matawan Formation. Torrey Bot..Club Bull. 31: 67—82. . 1905a. Additions to the fossil flora from Cliffwood, New Jersey. Torrey Bot. Club Bull. 32: 43-48. . 1905b. The flora of the Cliffwood Clays. New Jersey Geol. Survey Ann. Rept. 1905: 135-172. . 1906. Contribution to the Mesozoic flora of the Atlantic coastal plain. Torrey Bot. Club Bull. 33: 163—182. . 1908. A new Cretaceous Bauhinia. Torreya 8: 218-219. . 1910. A revision of the fossil plants of the genus Nageiopsis of Fontaine. U. S. Nat. Museum Proc. 38: 185—195. . 1911a. Lower Cretaceous of Maryland. Maryland Geol. Survey: Lower Cretaceous 214-508. . 1911b. The flora of the Raritan Formation. New Jersey Geol. Survey Bull. 3: 1-233. 198 Berry, E. W. 1912. Notes on the geological history of the walnuts and hickories. The Plant World 15(10): 225-240. . 1914. Upper Cretaceous and Eocene floras of South Carolina and Georgia. U. S. Geol. Survey Prof. Paper 84: 1-229. . 1916a. The Lower Eocene flora of southeastern North America. U. S. Geol. Survey Prof. Paper 91: 1-481. . 1916b. Upper Cretaceous deposits of Maryland. Maryland Geol. Survey Rept. 1916: 757-901. . 1919. Upper Cretaceous floras of the eastern gulf region in Tennessee, Mississippi, Alabama, and Georgia. U. S. Geol. Survey Prof. Paper 112: 1-177. . 1922a. The flora of the Cheyenne Sandstone of Kansas. U. S. Geol. Survey Prof. Paper 129: 199-231. . 1922b. The flora of the Woodbine Sand at Arthur's Bluff, Texas. U. S. Geol. Survey Prof. Paper 129-G: 153—180. . 1924. The middle and upper Eocene floras of southeastern North America. U. S. Geol. Survey Prof. Paper 92: 1-206. . 1925. The flora of the Ripley Formation. U. S. Geol. Survey Prof. Paper 136: 1-94. . 1929a. The Allison flora. Canada Nat. Museum Bull. 58: 66-72. . 1929b. The Kootenay and lower Blairmore floras. Canada Nat. Museum Bull. 58: 28-54. . 1929c. The upper Blairmore flora. Canada Nat. Museum Bull. 58: 55-65. . 1930a. The flora of the Frontier Formation. U. S. Geol. Survey Prof. Paper 158-H: 129-133. . 1930b. Revision of the lower Eocene Wilcox flora of the Southeastern States with descriptionscfi new species, chiefly from Tennessee and Kentucky. U. S. Geol. Survey Prof. Paper 156: 1-196. . 1934. A lower Lance florule from South Dakota. U. S. Geol. Survey Prof. Paper 185-F. . 1939. Fossil plants from the Cretaceous of Minnesota, Wash. Acad. Sci. Jour. 29(8): 331-336. 199 Berry, E. W. 1941. Additions to the Wilcox flora from Kentucky and Texas. U. S. Geol. Survey Prof. Paper 193-E: 83-99. Bierhorst, David W. 1971. Morphology of Vascular Plants. MacMillan Co., New York. 560 p. Braun, E. L. 1950. Deciduous forests of eastern North America. Hefner Pub. Co., New York (Facsimile, 1964). 596 p. Brown, R. W. 1933. Fossil plants from the Aspen shale of south- western Wyoming. U. S. Nat. Museum Proc. 82(12): 1-10. . 1939. Fossil plants from the Colgate Member of the Fox Hills Sandstone and adjacent strata. U. S. Geol. Survey Prof. Paper 189-I: 239-275. . 1946. Fossil plants and Jurassic-Cretaceous boundary in Montana and Alberta. Amer. Assoc. Pet. Geol. Bull. 30: . 1950. Cretaceous plants from southwestern Colorado. U. S. Geol. Survey Prof. Paper 221-D: 45-53. . 1956. New items in Cretaceous and Tertiary floras of western United States. Wash. Acad. Sci. J. 46(4): 104-108. . 1962. Paleocene flora of the Rocky Mountains and Great Plains. U. S. Geol. Survey Prof. Paper 375: 1-119. Buchholz, J. I. 1938. Cone formation in Sequoia gigantea. I. The relation of stem size and tissue development to cone formation. II. The history of the seed cone. Amer. J. Bot. 25(4): 296— 305. . 1939. The generic segregation of the Sequoias. Amer. J. Bot. 26(7): 535-538. Buell, M. F. 1939. Peat formation in the Carolina bays. Torrey Bot. Club Bull. 66: 483-487. Capps, S. R. 1940. Geology of the Alaska railroad region. U. S. Geol. Survey Bull. 907: 1-201. Chaloner, W. G. 1969. Triassic spores and pollen. In: Tschudy, R. H. and Scott, R. A. (eds.) Aspects of Palynology. Wiley- Interscience, New York: 291-309. Chamberlain, C. J. 1935. Gymnosperms, structure and evolution. U. of Chicago Press, Chicago. 484 p. ’h-hnnji ‘ l \ 4H; 200 Chaney, R. W. 1924. Quantitative studies of the Bridge Creek flora. Amer. J. Sci. 8(44): 127-144. . 1925. A comparative study of the Bridge Creek flora and the modern redwood forest. Carnegie Inst. Wash. Pub. 349: 1-22. . 1950. A revision of fossil Sequoia and Tomodiwm in western North America based on the recent discovery of Metasequoia. Am. Phil. Soc. Trans. 40(3): 171-263. Chaney, R. W. and Axelrod, D. I. 1959. Miocene floras of the Columbia Plateau. Carnegie Inst. Wash. Pub. 617: 1-237. Chaney, R. W. and Sanborn, E. I. 1933. The Goshen flora of west central Oregon. Carnegie Inst. Wash. Pub. 439: 1-103. Chebotorev, N. P. 1966- Theory of stream runoff. Israel Prog. for _ Sci. Translations, Ltd., Jerusalem. 464 p. ' Childers, B. S. and Smith, B. Y. 1970. Abstracts of thesis concerning ‘ the geology of Utah to 1966. Utah Geol. and Mineral. Survey ' Chu, K. and Cooper, W. S. 1950. An ecological reconnaissance in the native home of Metasequoia gZyptostroboides. Ecology 31: 260-278. Clark, F. R. 1928. Economic geology of the Castlegate, Wellington and Sunnyside quadrangles, Carbon County, Utah. U. S. Geol. Survey Bull. 793: 1-165. Cleavinger, H. B., 11. 1974. Paleoenvironments of deposition of the Upper Cretaceous Ferron Sandstone near Emery, Emery County, Utah. Brigham Young Univ. Geol. Studies 21: 247-274. Cobban, W. A. and Reeside, J. B., Jr. 1952. Correlation of the Cretaceous formations of the Western Interior of the United States. Geol. Soc. Amer. Bull. 63(10): 1011-1043. Cockerell, T. D. A. 1916. A Lower Cretaceous flora in Colorado. Wash. Acad. Sci. J. 6: 109-112. Corner, E. J. H. 1966. The natural history of palms. U. of Calif. Press, Berkeley. 393 p. Cotter, E. 1971. Paleoflow characteristics of a late Cretaceous river in Utah. J. Sed. Pet. 41(1): 129-138. . 1975a. Deltaic deposits in the Upper Cretaceous Ferron Sandstone, Utah. In: Broussard, M. L. S. (ed.) Deltas, models for exploration. Houston Geol. Soc.: 471—484. 201 Cotter, E. 1975b. Late Cretaceous sedimentation in a low-energy coastal zone: the Ferron Sandstone of Utah. J. Sed. Pet. 45(3): 669-685. Cross, A. T. 1968. Technique of preparation of Utah sediment. Unpbl. laboratory preparation sheet, Mich. State Univ., East Lansing. Cross, A. T., Maxfield, E. B., Cotter, E., and Cross, C. C. 1975. Field guide and road log to the western Book Cliffs, Castle Valley, and parts of the Wasatch Plateau. Brigham Young Univ. Geol. Studies 22(2): 1-132. Cross, A. T. and Singh, H. D. 1976. Palynologic indicators of paleoenvironments of Upper Cretaceous coals. (In preparation) Darrah, W. C. 1960. Principles of Paleobotany. The Ronald Press Co., New York. 295 p. Daugherty, L. H. 1941. The upper Triassic flora of Arizona. Carnegie Inst. Wash. Pub. 526: 1-108. Dawson, J. W. 1882-1883. On the Cretaceous and Tertiary flora of British Columbia and Northwest Territory. Roy. Soc. Canada Trans. 1(4): 26-90. . 1894. On new species of Cretaceous plants from Vancouver Island. Roy. Soc. Canada Trans. 2(4): 53-71. Debey, M. H. and Ettinghausen, C. 1859. Die urweltlichen Acrobryen des Kreidegebirges von Aachen und Maestricht: Akad. Wiss. Wien. Denkschr., Math.-naturw. K1., 17: 183-248. Dietz, R. S. and Holden J. C. 1970. Reconstruction of Pangaea: Breakup and dispersion of Continents, Permian to Present. J. Geophysical Res. 75: 4939-4956. Dilcher, D. L. 1963. Cuticular analysis of Eocene leaves of Ocotea obtusifblia. Amer. J. Bot. 50: 1-8. . 1973a. A paleoclimatic interpretation of the Eocene floras of southeastern North America. In: Grahm A. (ed.) Vegetation and Vegetational History of Northern Latin America. Elsevier Sci., New York: 39-59. . 1973b. A revision of the Eocene flora of southeastern North America. The Paleobotanist 20(1): 7-18. . 1974. Approaches to the identification of angiosperm leaf remains. Bot. Rev. 40: 1-157. 202 Doelling, H. H. 1972. Central Utah Coal Fields: Sevier-Sanpete, Wasatch Plateau, Book Cliffs and Emery. Utah Geol. and Mineral. Survey Mono. Series 3: 1-496. . 1972. Coal in the Sevier-Sanpete Region; Plateau-Basin and Range Transition Zone, Central Utah. Utah Geol. Assoc. Dorf, E. 1938. Upper Cretaceous floras of the Rocky Mountain region; I. Stratigraphy and paleontology of the Fox Hills and lower Medicine Bow formations of southern Wyoming and midwest Colorado. Carnegie Inst. Wash. Pub. 508: 1-78. . 1940. An illustrated catalogue of Mesozoic and Early g Cenozoic plants of North America. Science 91: 477-478. fl . 1942. Upper Cretaceous floras of the Rocky Mountain L region; 11. Flora of the Lance formation at its type locality,. 4 Niobrara County, wyoming. Carnegie Inst. Wash. Pub. 508: 19-159. ' . 1952. Critical analysis of Cretaceous stratigraphy and I. paleobotany of the Atlantic coastal plain. Bull. Amer. Assoc. Pet. Geol. 36: 2161-2184. . 1959. Climatic changes of the past and present. Contr. Mus. of Paleo., Univ. of Mich., Ann Arbor, 8(8): 181-210 . 1960. Climatic changes of the past and present. Amer. Y Scientist 48: 341. . 1964. The use of fossil plants in paleoclimatic inter- pretations. In: Narin, A. E. M. (ed.), Problems in Paleo- climatology. Interscience, London: 13-31. . 1969. Paleobotanical evidences of Mesozoic and Cenozoic climate changes. North Am. Paleontol. Conv., Chicago, Proc., A: 324-246. Dury, G. H. (ed.). 1970. Rivers and River Terraces. Praeger Pub., New York. 283 p. Dutton, C. E. 1880. Geology of the high plateaus, Utah. U. S. Geog. and Geol. Survey of the Rocky Mountain Region: 1-307. Eardley, A. J. 1934. Structure and physiography of the southern Wasatch Mountains, Utah. Michigan Acad. Sci., Arts and Letters 19: 377-400. Eckenwalder, J. E. 1976. Re-evaluation of Cupressaceae and Toxodiaceae: a proposed merger. Madrono 23(5): 237-300. 203 Edwards, W. N. 1955. The geographical distribution of past floras. Adv. Sci., London 46: 1-12. Ellis, C. H. and Tschudy, R. H. 1964. The Cretaceous megaspore genus ArceZZites. Miner. Micropaleont. 10: 73-79. Endo, S. 1934. The Pleistocene flora of Japan and its climatic significance. Johns Hopkins Univ. Studies Geol., Baltimore 11: 251-261. Esau, K. 1952. Plant anatomy. John Wiley and Sons, New York. 767 p. Fernald, M. L. 1950. Gray's Manual of Botany, 8th ed., Amer. Book Co., New York. 1632 p. Fisher, D. J., Erdmann, C. E. and Reeside, J. B., Jr. 1960. Cretaceous and Tertiary formations of the Book Cliffs, Carbon, Emery, and Grand Counties, Utah, and Garfield and Mesa Counties, Colorado. U. S. Geol. Survey Prof. Paper 332: 1-80. Fisk, H. N. 1947. Fine-grained alluvial deposits and their effects on Mississippi River activity. War Dept., Corps of Engineers, Mississippi River Comm., Waterways Experiment Station, Vicksburg, Mississippi. . 1952. Mississippi River valley geology: relation to river regime. Amer. Soc. Civ. Eng. Trans., 117: 667-689. Fontaine, W. M. 1889. The Potomac or Younger Mesozoic flora. U. S. . 1892. Description of some fossil plants from the Great Falls coal field of Montana. U.S. Nat. Mus. Proc. 15: 487-495. . 1893. Notes on some fossil plants from the Trinity Division of the Comanche Series of Texas. U. 8. Nat. Mus. Proc. 16: 261-282. . 1905a. Notes on some Lower Cretaceous (Kootanie) plants from Montana. U. S. Geol. Survey Mon. 48: 284-315. the Older Potomac of Virginia and Maryland. U. S. Geol. Survey Mon. 48: 476-599. Forrester, R. 1893. Coal fields of Utah. U. S. Geol. Survey Mineral Resources: 511-520. . 1905b. Report on various collections of fossil plants from - 6Txax fir. .‘ “ m7 '__,_- m ' ‘7' 1’,ng fi. 204 Gies, T. F. 1972. Palynology of sediments bordering some Upper Cretaceous strand lines in Northwestern Colorado. Doctoral Dissert., Mich. State Univ., East Lansing. Gilluly, J. 1963. The tectonic evolution of the western United States. Geol. Soc. London Quart. Jour. 119: 133-174. Gould, H. R. and Morgan, J. P. 1962. Coastal Louisiana swamps and marshlands, field trip no. 9. In: Rainwater, E. H. and Zingula, R. R. (eds.), Geology of the Gulf Coast and Central Texas Guidebook of Excursions. Houston Geol. Soc., Houston: 287-341. Gray, R. J., Potalski, R. M. and Schapiro, N. 1966. Correlation of Coal Deposits from Central Utah. Utah Geol. and Mineral. Survey Bull. 80: 55-79. Gunnison, J. 1855. U. S. Pacific Railroad Exploration 2: 62-66. Hale, L. A. 1959. Intertonguing Upper Cretaceous sediments of Northeastern Utah-Northwestern Colorado. In: Washakie, Sand Wash, Piccance Basins. Rocky Mtn. Assoc. Geology. 11th Field Conf. Guidebook: 55-66. . 1972. Depositional history of the Ferron Formation, Central Utah. In: Baer, J. L. and Callaghan E. (eds.), Plateau-Basin and Range Transition Zone, Central Utah. Utah Geolog. Assoc. Pub. 2: 29-40. Hale. L. A. and Van de Graaff, F. R. 1964. Cretaceous Stratigraphy and facies patterns -- Northeastern Utah and adjacent areas. Intermountain Assoc. Pet. Geologists Guidebook, 13th Ann. Field Conf.: 115-138. Hall, J. W. 1974. Cretaceous Salviniaceae. Annals Mo. Bot. Garden 61(2): 354-367. Hall, N., Johnson, R. D. and Chippendale, G. M. 1970. Forest Trees of Australia. Australian Gov. Pub. Service, Canberra. 333 p. Hall, T. F. and Penfound. W. T. 1943. Cypress-gum communities in Blue Girth Swamp near Selma, Alabama. Ecology 24: 208-217. Hays, J. D. 1960. A study of the South Flat and related formations of Central Utah. M. S. Thesis, Ohio State Univ., Columbus. Hear, 0. 1874. Die Kreide-Flora der arctischen Zone. In: Flora fossilis arctica, Band 3, Heft 2: Kgl: Svenska vetenskapsakad. handlingar, 12(6): 1-140. 205 Heer, O. 1882. Die Fossile Flora Gronlands sec. 1. Flora Fossile Arctica 6(2): 1-112. . 1883. Die Fossile Flora der Polarlander sec. 11. Flora Fossile Arctica 7: 1-46. Hickey, L. J. 1973. Classification of the architecture of dicotyledon- ous leaves. Amer. J. Bot. 60(1): 17-33. Hickey, L. J. and Hodges, R. W. 1975. Lepidopteran leaf mine from the early Eocene Wind River Formation of northwestern Wyoming. Science 189: 718-720. Hintze, L. F. 1973. Geologic history of Utah. Brigham Young Univ. Geol. Studies 20(3): 1-181. Hollick, A. 1898. Additions to the paleobotany of the Cretaceous formation on Staten Island. Ann. New York Acad. Sci. 11: 415-430. 4%: ‘6" wuss-1" . 1904. Additions to the paleobotany of the Cretaceous formation on Long Island. Bull. New York Bot. Garden: 403-418. . 1906. The Cretaceous flora of Southern New York and New England. U. S. Geol. Survey Mono. 50: 1-219. . 1930. The Upper Cretaceous floras of Alaska. U. S. Geol. Survey Prof. Paper 159: l-ll9. . 1936. The Tertiary floras of Alaska. U. S. Geol. Survey Prof. Paper 182: 1-185. Hollick, A. and Jeffrey, E. C. 1906. Affinities of Cretaceous plant remains commonly referred to Damniara and Brachyphyllum. Amer. Naturalist 40: 189-216. . 1909. Studies of Cretaceous coniferous remains from Kreischerville, New York. Mem. New York Bot. Garden 3: 1-76. Howard, J. D. 1966. Characteristic trace fossils in Upper Cretaceous sandstone of the Book Cliffs and Wasatch Plateau. In: Central Utah Coals: A Guidebook Prepared for the Geol. Soc. Amer. and Assoc. Soc. Utah Geol. Mineral. Survey Bull. 80: 35-53. . 1966. Sedimentation of the Panther Sandstone Tongue. In: Central Utah Coals: A Guidebook Prepared for the Geol. Soc. of Amer. and Assoc. Soc. Utah Geol. and Mineral. Survey Bull. 80: 23-33. . 1966. Upper Cretaceous Panther Sandstone tongue of east central Utah, its sedimentary facies and depositional environ- ments. Doctoral Dissert. Brigham Young Univ., Provo. 155 p. 206 Hoyt, J. H. and Weimer, R. J. 1965. The origin and significance of Qphiomorpha (Halemenites) in the Cretaceous of the Western Interior. In: wyoming Geol. Assoc. Guidebook 19th Field Conf. Sedimentation of Late Cretaceous and Tertiary Outcrops, Rock Springs uplift: 203-207. Hunt, R. E. 1954. South Flat Formation, new Upper Cretaceous Formation of central Utah. Amer. Assoc. Pet. Geol. Bull. 1 38(1): 118-128. Huttel, C. 1975. Root distribution and biomass in three ivory.coast. rain forest plots. In: Golley, F. B. and Medina, E. (eds.) 1975, Tropical ecological systems, trends in terrestrial and aquatic research. Springer-Verlag, New York. Imlay, R. W. and Reeside, J. B., Jr. 1954. Correlation of the Cretaceous formations of Greenland and Alaska. Bull. Geol. Soc. Amer. 65: 223-246. Jeffrey, E. C. 1906. The would reactions of Brachyphyllum. Annals Bot. 20: 383-394. . 1911. Affinities of Geinitzia graciZimiZZa. Bot. Gaz. 51: 21.-27o Katich, P. J. 1951. The stratigraphy and paleontology of the Pre-Niobrara Upper Cretaceous rocks of Castle Valley, Utah. Ohio State Univ. Press. 206 p. . 1953. Source direction of the Ferron Sandstone in Utah. Amer. Assoc. Petrol. Geol. Bull. 37: 858-861. . 1954. Cretaceous and Early Tertiary stratigraphy of central and south-central Utah. In: Geier, A. W. (ed.), Geology of portions of the high plateaus and adjacent canyon lands central and south-central Utah. Intermountain Assoc. Petrol. Geol. 5th Ann. Field Conf.: 42-54. Kidson, Evan J. 1971. Palynology and paleoecology of the Buck Tongue of the Mancos Shale (Upper Cretaceous) from east central Utah and western Colorado. Doctoral Dissert. Mich. State Univ., East Lansing. Knowlton, F. H. 1900. Flora of the Montana formation. U. S. Geol. Survey Bull. 163: l-117. . 1905. Fossil plants of the Judith River beds. U. S. 6 I- q‘-. )7? 207 Knowlton, F. H. 1907. Description of a collection of Kootanie Plants from the Great Falls CoalField of Montana. Smithson. Misc. Coll. 50(1): 105-128. . 1916. Contributions to the geology and paleontology of San Juan County, New Mexico. U. S. Geol. Soc. Prof. Paper . 1917a. A fossil flora from the Frontier Formation of southwest Wyoming. U. S. Geol. Soc. Prof. Paper 108-F: 73-94. . 1917b. Fossil floras of the Vermejo and Raton Formations of Colorado and New Mexico. U.S. Geol. Survey Prof. Paper 101: 223-455. . 1922. The Laramie flora of the Denver basin; with a E review of the Laramie problem. U. S. Geol. Survey Prof. ; Paper 130: 1-175. ‘ . 1924. Flora of the Animas Formation. U. S. Geol. Survey } 4 Prof. Paper 134: 71-117. 35.. .. . 1930. The flora of the Denver and associated Formations of Colorado. U. S. Geol. Survey Prof. Paper 155: 1-139. Lammons, J. M. 1968. The palynology and paleoecology of the Pierre Shale (Campanian-Maestrichtian) of northwestern Kansas and environs. Doctoral Dissert., Mich. State Univ., East Lansing. LaMotte, R. S. 1952. Catalogue of the Cenozoic Plants of North America through 1950. Geol. Soc. of Amer. Mem. 51: 1-381. Lawrence, G. H. M. 1951. Taxonomy of Vascular Plants. MacMillan Co., New York. 823 p. Lawyer, G. F. 1972. Sedimentary features and paleoenvironment of the Dakota Sandstone (early Upper Cretaceous) near Hanksville, Utah. Brigham Young Univ. Geol. Studies 19(2): 89-120. Lee, W. T. 1912. Coal fields of Grand Mesa and West Elk Mountains, Colorado. U. S. Geol. Survey Bull. 541-D: 135-140. Leopold, L..B., Wolman, M. G. and Miller, J. P. 1964. Fluvial processes in geomorphology. W. H. Freeman Co.,San Francisco. 522 p. Lesquereux, L. 1874. Contributions to the fossil flora of the western Territories. Part 1. The Cretaceous flora. U. S. Geol. and Geog. Survey Terr. Rept. 6: 1-136. 208 Lesquereux, L. 1878. Contributions to the fossil floras of the western territories. Part 2. The Tertiary flora. U. S. Geol. Survey . 1883. Contributions to the fossil flora of the western territories. Part 3. The Cretaceous and Tertiary floras. U. S. Geol. Survey Terr. Rept. 8: 1-283. . 1888. Fossil plants collected at Golden, Colorado. Harvard Coll. Mus. Comp. Zoology Bull. 16: 43-59. . 1892. The flora of the Dakota group. U. S. Geol. Survey Mon. 17: 1-226. . 1895. Cretaceous fossil plants from Minnesota. Minnesota Geol. Survey 3: 1-22. Little, E. L. and Wadsworth, F. H. 1964. Common trees of Puerto Rico and the Virgin Islands. U. 8. Dept. of Agriculture, Forest Serv. Lohrengel, C. 1969. Palynology of the Raiparowits Formation, Garfield County, Utah. Brigham Young Univ. Geol. Studies 16(3): 61-180. Lupton, C. T.‘ 1916. Geology and coal resources of Castle Valley in Carbon, Emery, and Sevier Counties, Utah. U. S. Geol. Survey Bull. 628: 1-88. Maberry, J. 0. 1968. Sedimentary features of the Blackhawk Formation (Cretaceous) at Sunnyside, Carbon County, Utah. U. S. Geol. Survey open-file report. 180 p. . 1971. Sedimentary features of the Blackhawk Formation (Cretaceous) in the Sunnyside District, Carbon County, Utah. U. S. Geol. Survey Prof. Paper 688: 1-44. MacGinitie, H. D. 1937. Eocene Weaverville flora of California. Carnegie Inst. Wash. Pub. 465: 1-113. . 1941. A middle Eocene flora from the central Sierra Nevada. Carnegie Inst. Wash. Pub. 534: 1-178. . 1969. The Eocene Green River flora of northwestern Colorado and northeastern Utah. Univ. Calif. Pub. Geol. Sci. 83: 1-140. MacNeal, D. L. 1958. The flora of the Upper Cretaceous Woodbine Sand in Denton County, Texas. Acad. Nat. Sci. Phil. 10: 1-152. Masters, C. D. 1966. Sedimentology of the Mesa Verde Group and of the upper part of the Mancos Formation (Upper Cretaceous), northwestern Colorado. Doctoral Dissert., Yale Univ.ifimr Haven. 88 p. ‘=»X.—rI-_1- n. 5'0“; :1] IE ...I. A 209 Masters, C. D. 1967. Use of sedimentary structures in determination of depositional environments, Mesaverde Formation, Williams Fork Mountains, Colorado. Am. Assoc. Pet. Geol. Bull. 51(10): 2033-2043. Matsuo, H. 1967. A Cretaceous solvinia from the Hashima Island (Gunkan jima), outside of Nagasaki Harbor, West Kyushu, Japan. Trans. Proc. Paleontol. Soc. Jap. 66: 49-55. May, F. E. 1972a. A survey of palynomorphs from several coal-bearing horizons of Utah. In: Doelling, H. H., Central Utah Coal Fields: Sevier-Sanpete, Wasatch Plateau, Book Cliffs and Emery. Utah Geol. Min. Survey Mono. Series 3: 497-542. . 1972b. Palynology of the Dakota Sandstone (Middle. Cretaceous) near Bryce Canyon National Park, southern Utah. Geoscience and Man, Am. Assoc. Stratigraphic Palynologists Ann. Conf. McGookey, D. P. (coordinator). 1972. Cretaceous system. In: Mallory, W. W. (ed.), Geologic atlas of the Rocky Mountain Region. Geol. Soc. Am.: 190-228. McNaughton, S. J. and Wolf, L. L. 1973. General.Ecology. Holt, Rinehart and Winston, New York. 710 p. Miller, C. N. 1974. Pityostrobus haZZii, a new species of structurally preserved conifer cones from the Late Cretaceous of Maryland. Moberly, R., Jr. 1960. Morrison, Cloverly and Sykes Mountain Forma- tions, northern Bighorn Basin, wyoming and Montana. Geol. Soc. Am. Bull. 71: 1137-1176. Morisawa, W. 1968. Rivers. In: Fairbridge, R. W. (ed.), Encyclopedia of Geomorphology. Reinhold Book Corp., New York: 952-957. Munster, G. G. 1843. Beitrage zur Petrefacten-Kunde 6: 1-100. Newberry, J. S. 1891. The flora of the Great Falls coal field, Montana. Am. J. Sci., 3rd Ser. 41: 191-201. . 1895. The flora of the Amboy Clays. U. S. Geol. Survey . 1898. The later extinct floras of North America (edited by A. Hollick). U. S. Geol. Survey Mon. 35: 1-151. Numata, M. 1974. The flora and vegetation of Japan. Elsevier Sci., New York. 294 p. -__.-,,\ l .-;‘ ‘V 4 bu 210 Orlansky, R. 1970. Palynology of the Upper Straight Cliffs Sandstone, Garfield County, Utah. Utah Geol. & Mineralogy Survey Bull. 89: 57-75. Ostrom, J. H. 1964. A reconsideration of the paleoecology of hadrosaurian dinosaurs. Amer. J. Sci..262: 975-997. Pabst, M. B. 1968. The flora of the.Chuckanut Formation of north- western Washington. Univ. Calif. Pub. Geol. Sci. 76: 1-85. Parker, L. R. 1968. A reconnaissance of Upper Cretaceous plants from the Blackhawk Formation in central Utah, and their paleo- ecological significance. M. S. Thesis, Brigham Young Univ., Provo. 58 p. Pashley, E. F., Jr. 1956. The geology of the western slope of the Wasatch Plateau between Spring City and Fairview, Utah. Ohio Unpub. M. S. Thesis, Ohio State Univ., Columbus. Penfound, W. T. 1952. Southern swamps and marshes. Bot. Review 18: 413-446. Penfound, W. T. and Hall, T. F. 1939. A phytosociological analysis of a tupelo gum forest near Huntsville, Alabama. Ecology 20: 358-364. Penfound, W. T. and Hathaway, E. S. 1938. Plant communities in the marshlands of southeastern Louisiana. Ecol. Mono. 8: 1-56. Penny, J. S. 1947. Studies on the conifers of the Magothy flora. Amer. J. Bot. 34: 281-296. Peterson, J. A. (ed.). 1956. Geology and economic deposits of East Central Utah. Intermountain Assoc. Geol. Guidebook. Phillips, E. A. 1959. Methods of Vegetation Study. Holt, Rinehart and Winston, New York. 107 p. Pike, W. S. 1947. Intertonguing marine and nonmarine Upper Cretaceous deposits of New Mexico, Arizona, and southwestern Colorado. Geol. Soc. Amer. Mem. 24: 103. Powell, J. W. 1876. Report on the geology of the eastern portion of the Uinta Mountains and a region of country adjacent thereto. U. S. Geog. and Geol. Survey Terr. Rept. 2: 16-58. Rmmanujam, C. G. K. and Stewart, W. N. 1969a. Fossil wood of Taxodiaceae from the Edmonton Formation (Upper Cretaceous) of Alberta. Can. J. Bot. 47: 115-124. . 1969b. Taxodiaceous bark from the Upper Cretaceous of Alberta. Am. J. Bot. 56(1): 101-107. 211 Raunkiaer, C. 1934. The life-forms of plants and statistical plant geography. Oxford Univ. Press, Oxford. 632 p. Raven, P. H. and Axelrod, D. I. 1974. Angiosperm biogeography and past continental movements. Ann. Mo. Bot. Gard. 61(3): 539-673. Read, R. W. and Hickey, L. J. 1972. A revised classification of foesil palm and palm-like leaves. Taxon 21: 129-137. Reeside, J. B., Jr. 1957. Paleoecology of the Cretaceous seas of the western interior of the United States. In: Ladd, H. S. (ed.) Paleoecology. Geol. Soc. Amer. Mem. 67: 505-541. Richards, P. W. 1966. The tropical rain forest -- an ecological study. Cambridge Univ. Press, Cambridge. 450 p. Richardson, G. B. 1906. Coal in Sanpete County, Utah. U. S. Geol. Survey Bull. 285: 280-284. . 1907. Underground water_in Sanpete and central Sevier Valleys, Utah. U. S. Geol. Survey Water Supply Pap. 199. . 1909. The Book Cliffs coal field between Grand River, Colorado and Sunnyside, Utah. U. S. Geol. Survey Bull. 316: 302-320. Rigby, J. K. and Hamblin, W. K. (eds.). 1972. Recognition of ancient sedimentary environments. Soc. of Econ. Paleont. and Mineral. Spec. Pub. 16. 340 p. Rigby, J. R., Hamblin, W. K. and Young, R. G. 1966. Fieldtrip guide to Carbon County coal fields from Provo to Price and Sunnyside. Utah Geol. and Min. Survey Bull. 80: 131-164. Rigby, J. R., Hintze, L. F., and Welsh, S. L. 1974. Geologic guide to the northwestern Colorado Plateau. Brigham Young Univ. Geol. Studies 21(2): 1-117. Sarmiento, R. 1957. Microfossil zonation of the Mancos Group. Amer. Assoc. Pet. Geol. Bull. 41: 1683-1693. Sch0pf, J. M. and Cross, A. T. 1945. Plant microfossil investigations in western coals, a progress report (abs). Geol. Soc. Amer. Bull. 56: 1194. d Schumm, S. A. (ed.). 1972. River Morphology. Dowden, Hutchinson and Ross, Stroudsburg. 429 p, . 1968. Speculations concerning paleohydrologic controls of terrestrial sedimentation. Geol. Soc. Amer. Bull. 79: 1573-1588. 212 Seliacher, A. 1964. Biogenic sedimentary structures. In: Imbrie, J. and Newell, N. D. (eds.) Approaches to Paleoecology. John Wiley 6 Sons, New York: 296-316. Seward, A. C. 1926. The Cretaceous plant-bearing rocks of western Greenland. Royal Soc. London Phil. Trans. 215(3): 57-175. Shelford, V. E. 1963. The Ecology of North America. Univ. of Illinois Press, Urbana. 610 p. Sinnott, E. W., and Bailey, I. W. 1915. Foliar evidence as to the ancestry and early climatic environment of the angiosperms. y a» Amer. J. Bots 2: 15.16. I" . 1916. The climatic distribution of certain types of angiosperm leaves. Amer. J. Bot. 3. Smiley, C. J. 1966. Cretaceous floras from Kirk River Area, Alaska: Stratigraphic and climatic interpretations. Geol. Soc. Amer. ‘ J . 1969. Cretaceous floras of Chandler-Colville region, Alaska: Stratigraphy and preliminary floristics. Amer. Assoc. Pet. Geol. Bull. 53: 482-502. Sokolovskii, D. L. 1971. River runoff; theory and analysis. Translated from Russian by A. Wald. Pub. by Israel Prog. Sci. Translations, Jerusalem. 489 p. Spackman, W. 1949. The flora of the Brandon lignite: Geological aspects and a comparison of the flora with its modern equiva- lents. Doctoral Dissert., Harvard Univ., Cambridge. Spieker, E. M. 1946. Late Mesozoic and early Cenozoic history of central Utah. U. S. Geol. Survey Prof. Paper 205-D: 117-161. . 1949. Sedimentary facies and associated diastrOphism in the upper Cretaceous of central and eastern Utah. In: Longwell, C. R. (chairman), Sedimentary facies in Geologic history; symposium. Geol. Soc. Amer. Mem. 39: 55-81. . 1949. The transition between the Colorado plateaus and the Great Basin in central Utah. Utah Geol. Soc. Guidebook to Geol. of Utah 4: 106. . 1931. Wasatch Plateau coal field, Utah. U. S. Geol. Survey Bull. 819: 206. Spieker, E. M. and Baker A. A. 1928. Geology and coal resources of the Salina Canyon District, Sevier County, Utah. U. S. Geol. Survey Bull. 796-C: 125-170. 213 Spieker, E. M. and Reeside, J. B., Jr. 1926. Upper Cretaceous shore- line in Utah. Geol. Soc. Amer. Bull. 37: 429-438. . 1925. Cretaceous and Tertiary Formations of the Wasatch Plateau, Utah. Geol. Soc. Amer. Bull. 36: 435-454. Stam, M. B. 1956. Structural features of east central Utah and west central Colorado. In: Geology and economic deposits of east central Utah. Intermountain Assoc. Pet. Geol. 7th Ann. Field Conf.: 28. Stanton, T. W. 1894. The Colorado Formation. U. S. Geol. Survey Stephenson, L. W. 1942. Correlation of the outcropping Cretaceous formations of the Atlantic and Gulf coastal plain and Trans- Pecos, Texas. Geol. Soc. Amer. Bull. 53: 435-446. Sternberg, G. K. 1838. Versuch einer geognostischen botanischen Darstellung der Flora Vorwelt. Leipsic and Prague 2(7, 8): Stewart, R. C. (ed.). 1975. U. G. M. S. drills for coal. Utah Geol. Mineral. Survey Quart. Rev. 9(3): 3. Stokes, W. L. 1952. Lower Cretaceous in Colorado Plateau. Amer. Assoc. Pet. Geol. Bull. 36: 1766-1776. Stokes, W. L., Peterson, J. A., and Picard, M. D. 1955. Correlation of Mesozoic Formations of Utah. Amer. Assoc. Pet. Geol. Bull. 39(10): 2003-2019. Stone, J. F. 1971. Palynology of the Almond Formation (Upper Cretaceous), Rock Springs Uplift, wyoming. Doctoral Dissert., Mich. State Univ., East Lansing. Taff, J. A. 1906. Book Cliffs coal field, Utah, west of Green River. U. S. Geol. Survey Bull. 285-F: 289-302. . 1907. The Pleasant Valley coal district, Carbon and Emery Counties, Utah. U. S. Geol. Survey Bull. 316: 338-358. Taggart, R. E. 1973. Additions to the Miocene Sucker Creek Flora of Oregon and Idaho. Amer. J. Bot. 60: 923-928. Taylor, I. N. 1968. Application of the scanning electron microscope in paleobotany. Trans. Amer. Micros. Soc. 87(4): 510-515. Thayne, G. F. 1973. Three new species of petrified dicotyledonous wood from the Lower Cretaceous Cedar Mountain Formation of Utah. M. S. Thesis, Brigham Young Univ., Provo. 56 p. 214 Thiessen, R., and Sprunk, G. C. 1937. Origin and petrographic composition of the Lower Sunnyside Goal of Utah. U. S. Bureau of Mines Technical Paper 573: 34. Thomas, G. E. 1960. The South Flat and related formations in the northern part of the Gunnison Plateau, Utah. M. S. Thesis, Ohio State University, Columbus. Thompson, G. G. 1970. Paleoecology of palynomorphs in the Mancos Shale, Southwestern Colorado. Doctoral Dissert., Mich. State Univ., East Lansing. Toots, H. 1961. Beach indicators in the Mesaverde Formation. In: Symposium on Late Cretaceous rocks, wyoming and adjacent areas. : Wyoming Geol. Assoc. 16th Ann. Field Conf.: 165-170. 7 . 1962. Paleoecological studies on the Mesaverde Formation e in the Laramie Basin. M. S. Thesis, Univ. of wyoming, Laramie. ‘ Traverse, A. 1955. Pollen analysis of the Brandon lignite of Vermont. 7 U. S. Bureau Mines Rept. Invest. 5151: 1-107. Tschudy, R. H. 1961. Palynomorphs as indicators of facies environment in Upper Cretaceous and lower Tertiary strata, Colorado and Wyoming. In: Symposium on Late Cretaceous rocks, Wyoming and adjacent areas. Wyoming Geol. Soc. 16th Ann. Field Conf.: 53-54. . 1966. Associated megaspores and microspores of the Cretaceous genus Ariadnaesporites Potonie. U. S. Geol. Survey Prof. Paper 550-D: 76-82. Upshaw, C. F. 1962. Palynological zonation of the Upper Cretaceous Frontier Formation near Dubois, Wyoming. In: Cross, A. T. (ed.) Palynology in oil exploration -- a symposium. Soc. Econ. Paleontologists and Mineralogists Spec. Publ. 11: 153-168. Van de Graaff, F. R. 1972. Fluvial-deltaic facies of the Castlegate Sandstone (Cretaceous), East-Central Utah. J. Sed. Petrol. 4(3): 558-571. Visher, G. S. 1972. Physical characteristics of fluvial deposits. Soc. Econ. Paleontologists and Mineralogists Spec. Pub. 16: 84-97. Voigt, J. W., and Mohlenbrock, R. H. 1964. Plant Communities of Southern Illinois. Southern Illinois Univ. Press, Carbondale: 202 p. Ward, L. F. 1885. Sketch of Paleobotany. U. S. Geol. Survey, 5th Ann. Rept.: 357-452. 215 Ward, L. F. 1885. Synopsis of the flora of the Laramie Group. U. S. Geol. Survey Ann. Rept. 6: 399-570. . 1899. The Cretaceous Formation of the Black Hills as indicated by the fossil plants. U. S. Geol. Soc. Ann. Rept. 19(2): 521-946. Warner, M. M. 1949. A correlation study of the Mesozoic stratigraphy of Utah and the adjacent portions of surrounding states. M. S. Thesis, Brigham Young Univ., Provo. Webb, L. J. 1959. A physiognomic classification of Australian rain forests. J. Ecol. 47: 551-570. in. $.31; iii. 7F “fl, Weber, R. 1973. Salvinia coahuiZensis nov. sp., dek Cretacio superior de Mexico. Ameghiniana 10(2): 173-190. a":‘ s Weimer, R. J. 1960. Upper Cretaceous stratigraphy, Rocky Mountain area. Amer. Assoc. Pet. Geol. Bull. 44: 1-20. A Tr. ' Luau". " "A . 1960. Upper Cretaceous stratigraphy, Rocky Mountain area. Amer. Assoc. Pet. Geol. Bull. 44(1): 1-20 . 1961. Uppermost Cretaceous rocks in central and southern Wyoming and northwest Colorado. In: Symposium on Late Cretaceous rocks, wyoming and adjacent areas. Wyoming Geol. Assoc. 16th Ann. Field Conf.: 17-28. Wells, B. W. 1942. Ecological problems of the southeastern United States coastal plain. Bot. Rev. 8: 533-561. Wheeler, G. M. 1875. U. S. Geog. Surveys west of the 100th Meridian. Final Rept. 3. Wheelwright, M. 1958. Preliminary palynology of some Utah and Wyoming coals. M. S. Thesis, Univ. of Utah, Salt Lake City. 110 p. Whitmore, T. C. 1973. Palms of Malaya. Oxford University Press, London. 129 p. Wieland, G. R. 1916. La Flora Liasica de la Mixteca Alta. Departmento do Imprenta de la Secretaria de Fomento, Primera Calle de Betlemitas num. 8. Wilmarth, M. G. 1938. Lexicon of Geol. Names of the U. S. U. S. Geol. Soc. Bull. 896. Wolfe, J. A. 1969. Paleogene floras from the Gulf of Alaska region. Open-file Rep., U. 8. Dept. Interior Geol. Survey. 110 p. 216 Wolfe, J. A. 1971. Tertiary climatic fluctuations and methods of analysis of Tertiary floras. Palaeogeogr., Paleoclimatol., Palaeoecol. 9: 27-57. Wolfe, J. A. and Hopkins, D. M. 1967. Climate changes recorded by Tertiary land floras in northwestern North America. In: Changes in the Pacific. Sasaki, Sendai: 67-76. Wolman,1L.G., and Leopold, L. B. 1957. River flood plains: some observations on their formation. U. S. Geol. Survey Prof. Paper 282-C. Young, R. G. 1955. Sedimentary facies and intertonguing in the Upper Cretaceous of the Book Cliffs, Utah-Colorado. Geol. Soc. Amer. Bull. 66(2): 177-201. . 1957. Late Cretaceous cyclii deposits, Book Cliffs, eastern Utah. Amer. Assoc. Pet. Geol. Bull. 41(8): 1760-1774. . 1966. Stratigraphy of coal-bearing rocks of Book Cliffs, Utah-Colorado. Utah Geol. Mineral. Soc. Bull. 80: 7-21. Zangerl, R. and Richardson, E. 8., Jr. 1963. The paleoecological history of two Pennsylvanian black shales. Fieldiana: Geol. Mem. 4: 1-352. Zapp, A. D. and Cobban, W. A. 1960. Some late Cretaceous strand lines in northwestern Colorado and northeastern Utah. U. S. Geol. Survey Prof. Paper 400-B: 246-249. -A‘. . PLATES "fl1 Figure 217 Plate 1 The southern end of the Wasatch Plateau viewed toward the west from near Emery, Utah. The Mancos Shale (Ms) forms the lower slopes of the Plateau while the Star Point Sandstone Formation (not distinguished on the photograph) and the Spring.Canyon Member (Sc) of the Blackhawk Formation are resistant cliff forming units midway up the face of the Plateau. The Blackhawk Formation (Bh) extends from the base of the Spring Canyon Member to the base of the resistant sandstone cliff at the top of the Plateau formed.from the Castlegate Sandstone (Cg) of the Price River Formation. The fossil plants discussed in this study were collected in the middle and lower portions of the Black- hawk Formation. The collection locality at Water Hollow Road in Salina Canyon viewed toward the northwest from Interstate 70. Several major fossil plant collections (Fp) were made in the alternating fluvial swamp sediments seen here. Numerous palm leaves and. other fossils can be seen on lower surfaces of the overhanging ledges including those discussed in Units M and 0, see text Figure 7 and Plate 11, Figure 2. A massive in-channel point bar (P) capped the swamp. Load casts and cross bedding in the point bar indicate that the river was flowing in a southwest direction in this particular meander. The collection locality at the Knight Mine in the Ivie Creek area of eastern Salina Canyon looking north. The Spring Canyon Member (Sc) of the Blackhawk Formation is the massive, white sandstone. Fossil plant collections (Fp) were made in fluvial sandstones and siltstones of floodplain origin above the littoral marine Spring Canyon sandstones. The entrance to the abandoned Knight Mine (K) and three coal dumps can be seen. 218 PLATE 1 A )- 5' 691A Figure l. 2. 219 Plate 2 A recent roadcut opposite (southeast) the Water Hollow Road collection locality seen in Plate 1, Figure 2. The alter- nating fluvial sandstones, siltstones, shales and coals indicate the local extent of the peat forming swamps near an actively meandering river. Note the several thinning coals (C) wedge-shaped sandstones (Se) and particularly the three thin lenticular channel fills (Cf) within the coal in the middle of the roadcut. A roadcut at the Pipe Springs locality in Salina Canyon looking north from Interstate 70. Wedge-shaped sandstones (Ss) and split coals (Sc) are present. A 10 m thick point bar (P) has several interesting fluvial sedimentary features such as cross bedding and load casts. Also present are 5 dm diameter fossil log casts. Plant collections made here were about 1/4 of the way up the slope at the right of the roadcut. The Castlegate sandstone (Cg) is near the top of the mountain approximately 170 m above the road. The lenticular point bar sandstones seen in text Figure 11 are about 300 meters to the right of the roadcut. 220 PLATE 2 #59 '1’.” Figure 221 Plate 3 Cyathea pinnata (MacGinitie) LaMotte. Portion of frond showing ultimate pinnules and veins. No. 6/1/68, 018-031. X 2. AspZenium dicksonianum Heer. Portion of frond. Secondary veins in pinnules could not be seen. Drawn from specimen no. 8/24/70, 013-023. Unknown fern 1. Tripinnate portion of a frond. Secondary veins can be seen. No. 8/28/70 11, 024-067. Unknown fern 1. Tripinnate portion of a frond. No. 8/28/70 11, 028-091. Unknown fern 1. Large ultimate pinnule. No. 8/28/70 11, 028-093. Osmunda hoZZicki Knowlton. Portion of frond. No. 7/30/70 11, 222 PLATE 3 Figure 223 Plate 4 Onoclea hebridica (7) (Forbes) Bell. Portion of a frond. Note the small gastropod to the left. Nos. 7/11/70 11, 153-338; 7/11/70 11, 153-341. Onoclea hebridica (7) (Forbes) Bell. Portion of a large frond. No. 7/11/70 11, 175-427. Brachyphyllum macrocarpum Newberry. Fragment of an older stem. Casts of a scale-like rhombobedral leaves can be seen. No. 8/19/70, 068C-100. Araucarites sp. Tip of leafy twig. No. 7/22/70, 050-083. Araucarites sp. Transverse view of a leafy twig showing arrangement of leaves. No. 7/22/70, 018-033. Araucarites sp. Portion of a leafy twig. No. 7/22/70, 062-097. Araucarites sp. Branching twig. No. Above R. R. cut, 091. Araucarites sp. Older leafy twig with leaf scars. Leaf length is no greater in this specimen than in younger ones. No. 7/22/70, 064-109. Brachyphyllum macrocarpum Newberry. Branching stem. No. 8/19/70, 018-053. 224 PLATE 4 .\. , townh9. ...—LL... 225 Plate 5 Figure l. BrachyphyZZum macrocarpum Newberry. Reconstruction of specimen no. 8/19/70, 054-119. X l. 226 PLATE 5 ..ov ‘l"~l 0'17," O ., In t, A ’ .. .7. ~ ‘. .37.?59449fi'3‘742a ' ...?— ’ 1 ”2', r! Fl’ 4- I- > 99 ms: —.-‘¢.'0~‘0'"\y 's’wr ”v V 3. . .... 6., .. an -.»:¢.¢e::~.zr~.eea m ‘_‘ mm. W, at. g ... f g. a 7‘4} \ ... id \.~. :‘m a;..D;n~aa./ ‘ 2 x‘ ‘i‘ \02‘ .. ' l " ‘ .' ‘ a {.9}: _.3"‘:,¢_I: .4; J., '4 .111”. ~ _. . ,; 5. > ”at- -‘ . , I, m -:' V tfi «19'. , r. a. fifluifiv' (a even-$3. l \ “ ‘13"- :7; was; .. P; a, x “56‘ "‘1. o H“Q‘ c. :v: a» ; A 0 e a 1; ‘ 411 l" .. P‘ . Alt "‘ h. ,2“ . Q I 3 0 w, an Figure 10. 227 Plate 6 Nageiopsis sp. Portion of a branching axis. No. 8/19/70, 0683-159. Nageiopsis sp. Leafy twigs showing spiral origin of leaves. No. 8/19/70, 006-016. Mbriconia cyclotoxon Debey and Ettingshausen. Branching axis with impressions of the scale-like leaves. No. 7/11/70 11, Moriconia cyclotoxon Debey and Ettingshausen. Branching axis with male strobili (Ms) at the end of the ultimate branches. No. 8/15/70, 031-091. X 2. Nageiopsis sp. Leaves with parallel venation. No. 8/19/70, 053-117. X 2. Podozamites sp. Leaf. No. 8/19/70, 059-125. Podozamites sp. Leaf with parallel venation. No. 8/13/70, 008-027. Nageiopsis sp. Branching axis with 3 orders of branching. No. 8/19/70, 005-019. Protophyllocladus polymorpha (Lesq.) Berry. Phyllode. No. Unit I, 699. Protophyllocladus polymorpha (Lesq.) Berry. Phyllode. No. 8/24/70, 001-004. 228 P L AT E 5 (.ng4: f" _. _, 229 Plate 7 Figure l. Moriconia cyclotoxon Debey and Ettingshausen. Reconstruction of specimen no. 8/20/70, 014-043. 230 PLATE 7 Figure 231 Plate 8 Widdringtonites reichii (Ettingshausen) Heer. Twig with small leaves. No. 8/15/70, 004-007. Protophyllocladus sp. 2. Reniform phyllode with serrate margin. No. 7/28/70 11, 022-041. Protophyllocladus polymorpha (Lesq.) Berry. Phyllode with the bases of two others (Pb) diverging from the stem. No. 8/24/70, 015-024. Sequoia cuneata Newberry. Short shoot. No. 7/11/70 II, 080-256. Protophyllocladus polymorpha (Lesq.) Berry. Portion of a phyllode showing petiole-like base, midrib and venation. No. 8/24/70, 021-031. Widdringtonites reichii (Ettingshausen) Heer. Branching stems. No. 8/15/70, 039-079. 232 PLATE8V Figure 10. 11. 12. 13. 233 Plate 9 Sequoia cuneata Newberry. Long and short shoots. No. 7/11/70 11, 168-417. Sequoia cuneata Newberry. Transverse view of a pistillate cone (probably immature) showing 5 peltate cone scales. No. 7/11/70 11, 058—186. Sequoia cuneata Newberry. Immature pistillate cone. No. 8/14/70, 001-003. Sequoia cuneata Newberry. Lower portion of a pistillate cone with attachment to a foliar stem. Cone scales have separated in dehiscence and have been preserved in an oblique angle. No. 8/24/70, 013-019. X 2. Sequoia cuneata Newberry. Pistillate cone showing approximate shape before dehiscence. No. 7/11/70 II, 057-185. Sequoia cuneata Newberry. Scales from pistillate cone. Note the features of the hexagonal scale at the top. No. 8/13/70, Sequoia cuneata Newberry. Seed(s). To its left is a short shoot and to its right is a portion of a pistillate cone. Sequoia cuneata Newberry. Twig with awl-shaped leaves. No. 8/24/70, 002-006. Sequoia cuneata Newberry. Older twig with leaf scars. No. 8/24/70, 003-008. Sequoia cuneata Newberry. Shoots bearing staminate cones (Sc). No. 8/24/70, 004-009. Sequoia cuneata Newberry. Short shoot. No. 8/24/70, 002-006. Sequoia cuneata Newberry. Long shoot with short shoots. No. R. R. cut, 1526. Sequoia cuneata Newberry. Long shoot with short shoots. No. 8/24/70, 006-010. 234 235 Plate 10 Figure 1. Sequoia cuneata Newberry. Reconstruction based upon specimen 236 PLATE 10 Figure 237 Plate 11 Geonomites imperialis (Dawson) Bell. Portion of a leaf near the base of the blade. No. Unit I, 693. X 0.5. Geonomitea imperialis (Dawson) Bell. A leaf "mat" seen on the undersurface of an overhanging ledge of Unit 0 at the Water Hollow Road locality. An incomplete leaf (A) with its apex toward the left is 1.2 m in length. A portion of a second leaf (B) with its apex toward the right has an expanded petiole base (pb), an unarmed petiole (p), and the lower portion of the leaf blade (b). It is about 1 m in length. These specimens could not be removed from the site. Geonomites imperiaZis (Dawson) Bell. Portion of a leaf. No. Unit I, 142. Sequoia cuneata Newberry. Cuticle removed from a leaf of the specimen illustrated in Plate 9, Figure 11, showing impressions of epidermal cells including 3 stomata (s). The guard cells were apparently sunken and are therefore not seen. Scale as indicated. 238 PLATE 11 I "‘