4—. —v THE STRATIGRAPHIC DISTRIBUTION OF OSTRACODA WITHIN THE TRAVERSE FORMATION OF THE MICHIGAN BASIN. Thesis for the Degree of M. S. MICHIGAN STATE COLLEGE DonaId Edmund Campau I950 0 o "“‘S _ .‘ SUPPLEMEMRY ‘ " MATLHIAL “ INBACKOFBOOK This is to certifg that the thesis entitled r "Stratigraphic Distribution of Ostracoda Within the Traverse Formation of the Michigan Basin." presented bg Donald 3. Carmen liay 32 , 1950 has been accepted towards fulfillment of the requirements or ' ‘ / ”A’Z‘Q’odegree in [ Major professor Date-M 0-169 m smIIGRmIIc DISTRIBUTION OF Osmcom nmn m; TRAVERSE FORMATION OF THE MICHIGAN mm by Donald.Edmnnd Cengea A THBBIB Submitted to the school 61' Giant. studies a: Michigan State College Of Agriculture end.tpp11ed Science in pertiel tuitillment of the requirements for the degree of MASTER OF SCIENCE Dopertnent at Geology and Geography h ACKNOWLEDGEMENTS The writer wishes to express his gratitude to Dr. W; A. Kelly; not only flor directing this study, but in giving freely of his time end fund of information, and also for his valuable criticism.of the manuscript. To Mrs. J. E. Smith, appreciation is given for editing the fossil descriptions and the text, end to Mr. F. V. Monsghsn who, giving his time, technical advice, and losn of equipment, made the photographs possible. The manuscript has been read by Dr. S. G. Bergquist who offered helpful suggestions for its improvement. Acknowledgements ere made to Mr. R. P. Grant, Mr. K. G. Welsworth. and Mr. G. W. Streight, of the lichigsn Geologicel Survey, for their sssistence in obtaining well cuttings. Thanks are elso due to Dr. C. S. Evans, union Gee Company of Csnads, Ltd.. Chsthsm, Ontario, for the well cuttings cf the three Csnedisn wells used in this study. 11 TABLE OF CONTENTS Acknowledgements. . . . . . . . . . . . . List of Illustrations . . . . . . . . . . Introduction............... Objectives of the Study . . . . . . . . . Classification.............. Systematic Classification of Ostracoda. . Stratigraphy of the Traverse Group. . . . Location of Wells used in this Investigation. . . llethods of Preparation . . . . . . . . . Orientation rerninology . . . . . . . . . Criteria Used for Describing Ostracoda. . Systematic Description of Ostracoda . . . Description of Bryosoan Acrogenia . . . . Description of Charom' Troohiliscns. . Interpretation of Cross Sections. . . . . O O O I interpretation of Distribution Chart of Ostracoda and BmIOHAorOEOni‘eeeeooooe Conclusions............... Bibliography............... iii 0 O O O Page . ii .13 . 13 flap 1 flap 2 “p8 Figure 1 Figure 2 Figure 8 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Plate 1 Plate 2 Plate 5 LIST OF ILLUSTRATIONS Outcrep of Traverse Formation in nichigan. . . . . . Location of wells Used in This Study . . . . . . . . index lap Showing Positions of Cross Sections. . . . DIAGRAIB Generalized Columar Section of Michigan . . . . . . Generalised Columns: Section of Equivalent Formations e o e e o e e e e e e o o e o o o e o e or10nt‘t1m0t O.tr..°°d‘ o e o o o o o o o o o e e e Cross Section A-I from Defiance County, Ohio to MnbtonComty,Ontario.......... eoee Cress Section A-B from Defiance County, Ohio to Outcrop at Black Lake, Cheboygan County, Michigan. Cross Section c-D frcn Chehoygan County, Hichigan t0 Lambton County, Ontario e e o o o o o e o e e o Cross Section E-F from Wayne County to Montcalm County o e e ego e e e e e e o e o e e e e e e e o Cross Section 6-H from iosco Township to Hartland TWhip' Livingston County. e o e e e o e o e o e Distribution. Chart of Ostracoda and Bryosoan Acrogenia in the Traverse Formation. . . . . . . . PLATES EIpthiont’fPlatSl.............. ExplmutionofPlatoz.............. Explmation or Plat. 3 O O O O O O O O O O O O O Q C O O C O O O O C O O O O O O O O O O O O O O O 0 iv Page .3 .12 .39 .16 .52 . In pocket .55 .54 .55 e In pocket .46 .47 .48 .49 .51 MODUOTIOI liedcrn ostraccda are snall bivalve crustaceans nest of which live in the sea, although some live in fresh water. Their adaptability to changing environmental conditions shes then cos-son today and probably explains the occurrence of fossil cetracoda in a variety of ancient sediments ranging in age fron Ordovician to Recent. The fossil oetraeoda as nicrofcssils prove useful for correlation purposes because they have a relatively short geologic range, are abundant, wide spread and not readily destroyed by drilling operations. lost of the specimens used in this study were found in well cuttings fro: the middle Devonian Traverse Formation of hichigan (map 1 page 8, figure 1 page 4), or from equivalent strata, the hanilton Shale of Ontario and the Silica Shale, of Ohio (figure 2 page 5). Microfossile were also collected at type localities of fornatione of the Traverse Groupt because it was believed that those fossils night be of aid in the correlation of subsurface zones with those at the surface. Approximately 2,000 nicrofessils, nest of which were ostraccda, were studied. lticrcfcssils other than cstracoda, which have proven significant in this study, include the bryosoan, icrcgnia, and the oogonia of the charcphyte, Trochclcdiscus . I"In this paper the Traverse will be referred to as a group when the individual lithological subdivisions are sufficiently defined to be represented as units which can be used in geological napping. South of the outcrop area the die- tinctions between the subdivisions of the Traverse are difficult to the. The entire Traverse is therefore mapped as a single unit and is properly referred to as the Traverse Pei-nation. The cstracoda occurring in the Traverse Torution were classified into twenty-two genera. All the cstracoda obtained fron well samples are concen- trated in the lower half of the Traverse Formation. This vertical distribu- tion does not agree with that from surface exposures, because cstracoda have been collected from the younger as well as from the older nembers of the ex- posed Traverse Group. This discrepancy uy be explained by the presence of beds, near the center of the basin, younger than any occurring near the rin. Such an occurrence would suggest regressive overlap. It is worth noting that flake and naebius state that the Squaw Bay at the top of the Traverse is best represented towards the center of the nichigan Basin. OBJECTIVES O? THE STUDY The objective of this study ie to determine the extent to which ostra- coda can be used in soning the Traverse Formation, either by showing re- stricted ranges for a few genera, or by establishing a cannon sons for the overlapping portions of relatively long ranges of season ferns. i. To investigate the distribution of cstracoda within the Traverse Porntion. B. To determine if there is a single sons or a number of zones of cstracoda ' within the Traverse Pornticn. 0. To determine if the acute or sones follow the Michigan basin structure and 0 reflect subsurface structures in lower herisons. D. To find out if the sons or gene. pinch and swell within the Traverse ‘ ' remtien. and thus suggest the possibility that other fomtions, below or above, nay also pinch and swell. E. To nahe a faunal list of all cstracoda found in cuttings of certain wells drilled into the Traverse Fornation. r. ittenpt to show the relation “of the Silica shale of Ohio and the Hamilton shale of Ontario to the Traverse romtion of Iichigan. DOMINION OF CANADA ALCONA A ISABELLA .SAAC3/hlli SAGJNAI OAKLANaD TON INGRAM $74 IfiV/IH/ VAN BUREN C? CASS BRANCH JOSEPH "'INDI "N-A GENERALIZED COLUMNAR SECTION OF‘ MICHIGAN MICHIGAN GEOLOGICAL SURVEY DIVISION |949 SYSTEM. SERIES FORMATION.GROUP LITHOLOGY .HICKNESS ECONOMIC PRODUCTS , RECENT SAND. GRAVEL.CLAY, boulders. _ SAND. GRAVEL. PEAT. MARL. PLEISTOCENE GLACIAL DRIFT mm 0 IOOO FRESH WATER “PERMo-CARBONIFEROUS" "RED-BEDS" SHALE,CLAY.SANDY SHALEmsum GRAND RIVER SANDSTONE.Sandyshe|e 80-95 BUILDING STONEFRESH WATER PENNSYLVAN'AN SAGINAW SHALE,SANDSTONE,IImesIone,coaI 20-535 ggmg-gggL-‘RESH WATER' LIMESTONE. SANDY OR CHERTY BAY PORT LIMESTONESANDSTONE 2-I00 LIMESTONE.FRESH WATER MICHIGAN SHALE.xypsum.anhydrITI-. sandstone 0-500 GYPSUM "MICHIGAN STRAv" SANDSTONE 0-30 GAS _ FRESH WATER. BRINE MISSISSIPPIAN MARSHALL SANDSTONE.sandy shale I00 400 WWW STONE COLDWATER SHALE.sendsIone.IImeSTone 500 'IIOO SHALE. FRESH WATER SUNBURY SHALE 0-I40 BEREA-BEDFORD SANDSTONE,SHALE 0-325 GAS.OIL ELLSWORTH‘ANTRIM SHALEJImcsTone . IOO'950 SHALE,GAS _ LIMESTONE. OIL.GAS. TRAVERSE LIMESTONE.SHALE I00 800 FRESH WATER flLL SHALE. Limestone 0‘80 SHALE ROGERS CITY-DUNDEE LIMESTONE 0-475 L'MESTONE' (“L-6‘5 DEVON 'AN A :FMEE55:OVR:TEDROLOM ITE DETROIT RIVER QfiLg’mLTE-"M'°M-”" I50-I400 0IL.GAS.S'ALT. BRINEf Y FRESH WATER SYLVANIA SANDSTONE.SANDv DOLOMITE 0-550 GLASS SAND. FRESH WATER BOIS BLANC DOLOMITE,CHERTY DOLOMITE O-IOOO BASS ISLAND DOLOMITE 50-570 DOLOMITE. FRESH WATER SALINA SALT, DOLOMITE, Shalonnhydme 50-4000 SALT. GAS, OIL NIAGARAN SILURIAN Gum. Luge" Ema...) DOLOM'TE L ' H I50-800 LIMESTONE.DOLOMITE. Momshque- um BIuIT) . ”mm-3 ” OIL.GAS. FRESH WATER Catered) CINCINNATIAN Michmend)u ) SHALE.LIMESTONE 250-800 ORDOV'C'AN ayw .- m OIL GAS LIMESTONE TRENTON-DLACII RIVER LIMESTONE. DOLOMITE ZOO-IOOO FRESH WATER - ST. PETER SANDSTONE 0 - I50 FRESH WATER OZAORKIAN PRAIRIE DU CHIEN DOLOMITE.SI..I. 0- 4I0 R DOLOMITE. SANDY DOLOMITE. - CANADIAN HERMANSVILLE mm" I5 500 -LAKE SUPERIOR T CAMBRIAN Emma“) SANDSTONE 500-2000 Eg'ELSDJ"3ATSE§"‘ Jocobva It) (Copper Tomatoes) 8M! “"43“" SEMI-PRECIOUS GEM STONES "' II' ILLARNET GRANITE GRANITE. GNEISS.dI.rII...y..II. ALGONK'AN WWW" 302%?1IE‘”€JII‘AEC”'5" 2000 I230 SETEAPOERANPRREME' . . N .mTIIIo. 9 . (Iron femohocs) dolomite ”ARBLE ROAD METAL. BUILDING . LAURENTIAN SCHIST. GNEISS. GRANITE STONE.VERDE ANTIQUE.TALC. ARCHEAN GOLD SCHIST, GREENSTONE. REEWATIN SLATE ROAD NETAL FIGURE+ I GENERALIZED COLUMNAR SECTION FIGURE- 2 6 NORTHWESTERN M'CH {GAN SOUTHWESTERN OHIO ONTARIO Z S & HURON SH. ANTRIM SH. HURON SH. 5 <2 (I) <9 2' TRAVERSE HAMILTON GROUP GROUP E SILICA SH. 2", DELAWARE LS. > g COLUMBUS LS. ROGERCITY-DUNDEE DELAWARE .. West of CincinaTTi arch “ONONDOGA D.E.Campou CLASS IPIGATIM Bassler and Kellott (1054) divide the cstracoda into four superfanilies and nineteen fanilies with about 170 Paleosoic genera. Twelve new fanilies and 16'! new genera have since been proposed by Agnew (1942). The nunber of Paleozoic species alone is estinated at 8400 by Cooper (1942) although not all the new fanilies are generally accepted. The four superfanilies are listed below: 1. Lezrditacea z. BeEichiacea 3. Omidaeea 4. Ofleracea A total of twelve fanilies belonging to the Legrditacea, Benichiacea and Cm. idacea represented by twenty-two genera are known to occur. lost of those fall into the beEichiacea and Omidaeea. The nest semen genera are rennet-mega and guasillites which belong in the cmidaoea superfanily. The twenty-two genera are listed under both the superfanily and the fanily and will be described later (pages 17 to 35) in the order given in the list below. ‘ Further references to the fanilies are not nade, but the genera will be listed under the superfenily to which they belong. In general, authorities agree on the naJor divisions to which the genera are‘assigned but not on the fanilies. An example of disagreement is the genus Bglmella which has been assigned by Bassler and Kellett to the fanily Thlipsuridae and by Goryell and llalkin to the family when“... ' SYSTEMATIC CLASSIFICATION OF OSTRAOODA Superfuily Leperditacea Fanily Leperditellidae, Ulrich and Bassler Genus Aparchites Superfanily Beyrichiaeea Fanily Beyrichiidae, Jones Genus Gtenoloculina Gtenobolbina’ Richina Hollinella Panily Kirkbyidae, Ulrich and Bassler Genus Alphissites Ulrichia Panily Ileedenellidae, Ulrich and Bassler Genus Disygopleura Poloniella Panily Prinitiidae, Ulrich and Bassler Genus Halliella reniiy Youngiellidae, Ulrich Genus Bufina Panily Zygobolbidae, Ulrich and Bassler Genus Kloedenia - Superfunily Gypridacea Fanily Bairdiidae, Sara Genus Bairdia Fenily Baryohilinidae, Ulrich Genus Baryohilina l'enily Gytherellidae, Bars - Genus Penderodictya Family Quasillitidae, Goryell and ualkin Genus Jenningsina Quasillites Spinovina ranily Thlipsuridae, Jones Genus Buglyphella Hyphasnaphora Oetcnaria Thlipsura SWIM OF THE TRAVERSE GROUP A very good suuaary of the Traverse stratigraphy as exposed in lichigan is given in an article by Swaun (19”, pages 236 - 239) and is reproduced at length herewith (pages a. s). ' ' ”The Traverse Group is exposed in the northern part of the Lower Peninsula of Michigan in three areas, each separated Tron the other by moderate distances and each containing a rock section quite different from that of the others. The type area, the western one, berders Little Traverse Bay, Lake nichigan, in Emet and Charlevoix counties. The stratigraphic terminology of Pohl (1930) is used for this western area, except that his 'stages' are recognised as for- ntions. In ascending order these are the Gravel Point, the Charlevoix and the Petoskey forntions. Although the western area contains the type Traverse section, only the upper part of the group is here represented in outcrop. ”The most couplets section is exposed in the eastern area, in Alpena. and Presquo Isle eounties,-near Thunder Bay, Lake Huron. Warthin and Cooper (1935a, 1935b, 1943); Cooper. and Warthin (1941, 1942) have described the section in detail and have kindly allowed the author to use material on the stratigraphic succession in this region previous to its publication. The sequence recog- nixed here is that of their 1943 paper. In ascending order, the formations are Bell Shale, Rockport Quarry limestone, Perron Point formation, Genshaw fomtion, including the Killians line- stone member Just above the middle, newton Creek limestone, Alpena linestone, including the Dock Street clay lens at the top, Four Mile Den limestone, Norway Point formation, Potter Fara forea- tion, Thunder Bay limestone, and Squaw Say linestone. ”The third area of outcrops of the Traverse Group occurs in Oheboygan County and at The western edge of Presque isle County, about midway between the other two regions. This was named the Afton-Black Lake area by Mohair (1937 pp. 105-107), who has published the only recent account of these outcrops. Dr. S. A. Kelly, who has done much field work in this area, generously allowed use of his notes on stratigraphy of the region. The section up to and including the Killians linestone menber of the Genshaw fornation is easily correlated with the Thunder Bay section, though the Ferron Point thins greatly to the west and is only four feet thick at Black Lake, whereas the Genshaw below the Iillians is nore than twice as thick in the Afton area as it is in the eastern area. ”Above the Killians limestone member correlation is such less secure. i covered interval of five or ten feet separates the Killians member from an unnamed light gray sparingly fossili- fercus stylolitio limestone about thirty feet thick (since this article has been published this stylolitio limestone is now called the Koehler limestone by W. A. Kelly) which is best ex- posed in the abandoned Campbell Stone Conpany quarry north of Afton, Cheboygan County. Welloria aftonensis Warthin and a few cup corals are about t5; only fossils found in this lime- stone, which is stratigraphically equivalent but lithologi- cally dissimiliar to the upper part of the Genshaw formation. (This limestone is now classified as Lower Gravel Point by We Le I‘llye) "Unconfcrnably overlying this unnamed limestone is a very dark argillaceous limestone six to ten feet thick with numerous black shale partings. This dark limestone, which carries a poorly preserved coral-stromtopcroid fauna, can be considered the basal member in this region of the Gravel Point formtion, although it is stratigraphioally below the exposed base of the forumtion in the Traverse Bay region. Exposed portions of the Gravel Point formation above this member comprise chiefly gray limestones, some of which can be directly correlated with similiar beds in the type area. Long continuous sections are not known, and it seems certain from well records that shale beds are intercalated between the more resistent outcrcpping limestones and that the total thickness of the Gravel Point foremtion in this region is near eighty feet. 'Outcrops of beds above the Gravel Point formaticn occur only in one small area near Beebe School, one-half mile west and two and a half miles south of Afton, where about ninety feet of beds corresponding to the llorway Point formation and Potter rarm or equivalent Peteshey formation can be recog- nised. Several covered intervals and a dip unusually high for the lichigan basin make interpretation of this section difficult. The covered interval between the top bed, which carries a Potter Farm fauna, and the overlying intrim shale appears to be no more than ten feet; this shows that the Thunder Bay limestone and Squaw Bay dolomite or their equi- valents must be either lacking or extremely thin in the Afton region. “The section here recognised in the Afton-Black Lake area emprises in ascending order, Bell shale (unexposed and known only from wells, ) Rockport Quarry limestone, Ferron Point formation, Genshaw formation up to and including the Killians limestone member, a covered interval, unnamed style- litic limestone, Gravel Point formation with dark argillaceous limestone member at the base, a covered interval, beds equiv- alent to the Norway Point formation, aid the Potter Farm or Petoskey foruticn.‘ Q LOCATION OF WELIS USED III HIS INVESTIGATIOI The specific locations ofIwells in which fossil cstracoda, Charo h , and the hryosoan Acrogenia were found are given in the table which follows and also on map 2. NO. 12. 10 State Permit lo. Township County 15 Clinton hacomb 611 lorth Ellis Presque Isle 1213 Chesterfield laoomb 1254 Osceola Livingston 1309 Genoa Livingston 1395 Ft. Gratiot St. Clair 1562 Clyde St. Clair 2961 Canton Wayne 3247 Garfield Bay 4162 Walker Cheboygan 6069 Burnside Lapoer 6926 Ft. Gratiot St. Clair 7227 Lyon Oakland 9275 Greenleaf Sanilac 9426 Hartland Livingston 9766 Adrian Lenaweo 10036 Iosco Livingston 10610 Bloomfield Huron 10642 Avery lontmorenoy 10916 Fremont Sanilac 11001 Re Huron Ste out 11406 lhitney Arenas 11634 Rubicon Huron 11976 Sims Arenac 12035 Burtchvillo St. Clair 12163 Baldwin Iosco 12416 Howell Livingston 12506 Brookfio 1d Huron 12531 Burleigh Ioscc 12603 Howell Livingston 12696 West Branch Ogemaw 1290'! Windsor Huron 13026 Pt. Gratiot St. Clair 13130 Oscoda Oscoda 13637 llaricn Livingston 13669 uoffatt Arenas 13702 Kenockwoo St. Clair 13796 Iorth Plains Ionia 13897 Jerome lidlamd State Permdt lo. 13841 13665 13916 13922 14075 14120 14295 14549 14465 14577 14654 14664 14675 14763 14765 14636 14657 14936 14969 15072 15105 1 A 2 A Canade #12 Canada {us Canada #90 Ohio #1“ 11 Township rt e Gratiot Summer Arbola Clyde Garfield Genoa Bloomfield Owosso Moffatt Sparta Evergreen Summdt Arthur Clay JMuskegon Montcalm Wales Ellis ‘Uhles wales Sdenville Saginmw Outcrcp at Black Lake Moore Zombra Zone Adams Coun Ste 61‘” Gratiot Tuscola Ste c1311. Kalkaska Livingston. Huron Shiawaseee Arenas Kent Montcalm Mnson Clare St. Clair Muskegon Montcalm Ste Clair Cheboygan St. Clair St. Clair midland Saginaw' Cheboygan Lambton.County . Ontario Lambton.County . Ontario Lambton County . Ontario Defiance County . Ohio WELL SAMPLEs EXAMINED : ( FOR OSTRAOODA 7 N 05mm 0%“ 4‘ \ mam * "fiRESOUE ISLE 6‘ 00 0 L'b"; CHARLEVOIII 1 ANTRIM OTSEGO NONTMORENCII ALPENA g Q OW! V emu KALKASKA CRAWFORD OSCODA ALCONA TRAVERSE “m I Q seen I c \ WEXFORD LUISSAUKEE OGEMAW IOSCO MAN T § '5 [E rIOSCOMMOI1,.... w, j“ “m 0 b .mNAC .0976 MASON LAKE OSCEOLA CLARE GLADWIN “a, 2 ones \ A... em "4, HURON § eons BAY eases sen? OCEANA MECOSTA ISABELLA MIDLAND .sm NEWAVGO OLA m TUSC SANILAC "3'“ SAGINAW . T T “$0550" 103:” GRATIO .Is. 233.. I045" IIENT we GENESEE LAPEER Lu OTTAWA IONIA CLINTON s IAIASSEE k Th- V ALLEGAN GARRY EATON , INGRAM fig. a ”mum” m \l ens? sue m Bum RALAMAzoq CALHOUN JACKSON WASNTENAW WAYNE CANADA ST CASS BRANCH HILLSDALE LENAWEE MONROE JOSEPH .m. L A K 5 .—..—.-_..—-.—..a.-.-.- ' N D A N A I—nm m.—.-— 0—- ; O H ERIE “ma. um METHOD OF PREPARATIOI Most of the cstracoda examined were found free in the samples obtained from well cuttings. In the wells from St. Clair County, Michigan, Defiance County, Ohio, and Lambton County, Ontario, concentration was necessary, be- cause the Traverse Forwaticn is a silty shale. Samples were washed and fine material decanted off several times, which left a concentration of fossils that could be examined under the microscope. Material from the outcrop area was treated the same as the well cuttings. Mo further preparation was necessary. The cstracoda then were mounted on slides, and the depth below the Antrim along with the state permit number was recorded. The photography was done with a Graflex Camera mounted on a Spencer binocular microscope. Some of the specimens were coated with ammonium chloride to bring out the de- t‘il' e ORIENTATION TERMIIOLOG! In this study the orientation is tahen from the Journal of Paleontology, 1948, Volume 22, lo. 5, ”Ostracoda from the Middle Devonian Windon beds in western Mew York“ by Swartz and Oriel, who state: ”The tdrm, plenate end, was proposed for the end of the ostra- coda shell towards which the swing is directed, because this end tends to be relatively 'full' either in height, or in extension be- yond the hinge, or in both respects. The opposing end can then be termed 'the antiplenate end' 3 features toward the one or other end are 'adplenate' or 'antiplenate'.‘ The adplenate end in this study will be referred to as posterior and the antiplenato will be anterior. If the determination of a right valve is nmde from a lateral view the posterior end will be at the loft, (figure 3, page 16) and conversely the posterior end will be at the right for a left valve. ' 13 14 For some cstracoda: cg; Ponderodictn and ansillites, plenation is not worked and orientation by that method is not practical. Under those cir- cumstances, orientation is determined by the position of such features as flanges and spines, the former being anterior and the latter, posterior. (figure 3, page 16) CRITERIA USED II DESCRIBING OSTRACODA 1. Shape of carapace B. Position of greatest height 0. Position of greatest thickness D. Relative sharpness of anterior and posterior ends 2. Character of the. hinge line I. Overlap of the valves G. Location of spines, nodes, and sulci H. Surface ornamentation 1. Length and height of cstracoda in millimeters Ostracoda, unlike BrachioPoda and Mollusca, have no part of the carapace that can be classified as a protooonch and therefore developmental stages can not be made out in a single individual. A Because smny of the specimens found in this study do not completely satisfy the descriptions of species given by several paleontologists, the term “variant” has been introduced for those specimens which deviate in a minoradegree from the described and illustrated species of various authors. These variations are not consistent in any one group and variants in species may be mtation in a single species or growth stages. is an example of the latter, one can cite PondercdictE bispinulata variant ‘'H" on page so, the 15 weak ornamentation, small carapace suggests a young specimen rather than a new species. The significance of variations cannot be evaluated. As a re- sult the term ”variant” is used to imply variation from a form arbitrarily taken as type er norm.‘ ORENTAHON OF OSTRACODA .e—-— I 3- —_H I% —'—~ ANTIPLENATE hinge Iine PLENATE END END ANTERIOR POSTERICR POSTERIOR ANTERIOR D.E.C»‘»MPAU FIGURE 5 16 CINEMATIC MCRIPTIOIB 0! Demon ‘ cenne APARCHITB Jones 1669 ”Shell not over 3 u. long, equivalve, subovate or oblong: hinge.straight, ventral edge thickened, often beveled or channeled; surface convex, mostly in ventral half, smooth.“ (Shiner and Shrock, 1944, page 664) Agata variant ”A” Carapace ovate; greats“ height near center of the valve; greatest thickness posterior; straight hingOIine, slight overlap of the valves, surface reticulated. Length, 0.70 mm., height, 0.50 n. Bare in well cuttings. ' Lurchites variant 'B“ Carapace ovate in ldtOral view; greatest height near center of valve; greatest thickness near center; curved hinge line; valves nearly equal, surface granular. Length, 0.25 -., height, 0.50 an. Bare in well cuttings. ' Genus CTSIOLOCULIIA Bassler 1941. 'Tetradella-like shells with valves crossed transversely by four flat-topped, finely reticulated ridges separated by narrow furrows, and with the smrgins surrounded by a false border, which in the fesmle is swollen to form four to six loculi or brood chambers; right valve grooved on free margin to receive edge of left.“ (Shiner and Shroek, 1944, page 667) Ctenoloculina eieeti-ieesg (lax-thin) (plete 8, figures lei-ll) Carapace somiovate in lateral viewj greatest height in center of posterior half; anterior end sharper than blunt posterior; hinge line straight, valves equal; flee margin surrounded by a narrow false border; posterior node near dorsum low and eliptioal in shape, high lobe in center of posterior half slanting posteriorlyz lobe Just anterior of center of 17 16 valve high and curving posteriorly; anterior node near dorsum low: surface very finely reticulated. Length 1.00 e... height, 0.50 we. Bare in well cuttings. Ctenoloculina cioatricosa variant '1' This variant differs from the description of the holotype in having brood pits. It resembles the form figured by larthin (plate 1, figures 5-6) which he cells the female of the species. here in well cuttings. Ctonolooulina cioatricosa and its variant have been compared with the description and plates by Iarthim, 1954, page 209, (plate 1, figures 4-6) min agrees in all respects. 0 Come CTSMOBOLBIIA. Ulrich mo ”Straight-backed, typically with two, but in part with one, long subventral curving sulci dividing the surface into rather broadly convex lobes, and typically with rather inconspicuous submarginal frill along free edges.“ (Shiner and Shrock, 1944, peso 669) Ctenobolbina variant '1' (plate 2, figure 6) Carapace semiovate; greetest height et posterior end; straight hinge line, valves are equal; posteriorly curving salons and a node in center of valve near hinge line; finely reticulated surface. Length, 0.70 mm, height 0.40 e... Bare in well cuttings. ‘ Ctenobolbina variant "3" (plate 2, figure 5) Carapace semicvato; gredtest height in posterior half; straight hinge line, valves equal: posterior sulcus, node in center of valve that pro- jects above the hinge line, surface finely reticulated. Length, 0.70 m, height 0.40 ass. here in well cuttings. ' 19 Ctenobclhina variant '0' (plate 2, figure 8) cerepece seniovatez greetcst height in posterior end; straight hinge line, valves equal; posteriorly curving sulcus, node located in center of valve; surface finely reticulated. length. 0.00 .11., height 0.40 ea. Bare in well cuttings. multina variant "0" verient '0' is lihs werinnt 'A" except that the surface is granular. Length, 0.c0 n... height 0.35 -. Bare in well cuttings. ctcnchol‘cina variant 'l" (plate a. figure 2) cerepecc seniovate; grcitcet thickness in posterior end; straight hinge line; posteriorly curving auleue near center of the valve; large anterior node and a snall posterior node; anall flange near the ventral edge at the an- terior end. Length, 0.90 -., height, 0.40 n. Bare in well cuttings. ctenchclhig variant '0'“ cerepece seniovate: greetest height in posterior end; greatest thickness in the anterior and; straight hinge line; right valve overlaps left; large anterior node, weak posteriorly curving aulcus, weak posterior node; anterior end is sharper. Length, 1.10 n" heiylt 0.50 -. Rare in well cuttings. ° Whittle. variant '0' carapace seniovate; grcctcst height in posterior and; shell entericr node, posteriorly curving aulcuaz anterior and sheet pointed: finely reticu- lated surface. Length, 0.00 m, height 0.25 -. Bare in well cuttings. lens of the. ctenobolbina ferns found in this investigation resenhle the described species. 20 Genus RIGHIIA coryell and lalhin 1930 “Carapace subovate; hinge line straight; ventral nargin eon- vex; ends rounded, anterior end with a backward swing. Right valve overlaps the left. i nedian sulcus is bounded by nodes, or blunt spines, or a node and a spine. Surface of valve snooth, or very finely, to, or finely reticulated.“ (Coryell and Ialkin, 1980,page . Riohina variant “A” Carapace subovate in lateral view; greatest height in posterior end; greatest thickness in posterior and: anterior and sharp, posterior and blunt; straight hinge line; valves nearly equal; ncdian sulcus curving poa- tericrly; surface finely reticulated. Length, 0.70 n., height, 0.40 n. Bare in well cuttings. Genus HOLLIIELLA Corye11.192—S- ”Tapered edge of right valve fits into grooved hinge of left and protuberanoes near cardinal angles of right valve hinge with socket at their base, into dlich sockets corners of left valve fit; each species has three different ferns: (1) with wide frill all along margin except at anterior; (2) with sini- lar but narrower hill; and (3) with only a row of granules or spines representing frill.‘ (Shiner and Shrock, 1944, page 069) hollinella tricollina Van Pelt (plate 2, figure 4) Carapace seniovate in lateral visr 3 greatest height in posterior end; greatest thickness in anterior and; anterior and is sharp, posterior and is blunt; straight hinge line; equal valves; large anterior node near dorsun: posteriorly curving sulcus near center of valve: posterior node near horizon- tal lid-line and a posterior node near dorsun; finely reticulated surface. Length, 0.70 n., height, 0.40 n. i This specimen has been ccamarcd with the description and plates by Warthin, 1945 (page 79) and agrees in every respect. Very rare in well cuttings e 21 Hellinclila variant '1' (plate 2, figure 1) Carapace seniovate in lateral view; greatest height at posterior end; anterior and is sharp, posterior and is blunt; straight hinge line; posteriorly curving sulcus; large posterior node, small anterior node; reticulated surface. Length, 0.90 m, height, 0.60 In. Very rare in well MMIe Genus AHPEISSITES Girty 1910, sncnd Cooper 1941 'Carapace with a single, centrally located node or swelling and tee or norc carinae or false heels, parallel or subparallel to free mgins.’ (Shiner and Shroch, 1944, page 671) w. «Mates (Ulrich) (plate a, figure 13) Carapace subquadrate in lateral view; greatest height. at posterior end, greatest thickness in center of posterior half; free nrgin is striated parallel to free edge; heavy carina around each valve, nearly paralleling the ventral border, but cutting sharply across both ends: kirhbyan pit Just an- terior to center of valve; surface coarsely reticulated, valves equal. Length, 0.65 ms, height, 0.40 all. This specimen is very rare in well cuttings. ‘ this specimen has been compared with the description and plates by Warthin 1934,1pagc 214 (plate 1, figure 12) and agrees in every respect. flissitcs variant '1' differs fron Bhiaaites semis-tea (s.a.) by being ovate in leterel view} greatest thickness is in the anterior half, and the right valve overlaps the left. Length, 0.65 In», height, 0.30 -. this variant is rare in well cuttings. ‘ 22 Genus ULRICHIA Jones 1890‘ ' "Libs Prinitia, but has sharply defined node on each side of sulcus, which in this case is scarcely inpresscd; occasionally other nodes are present on ventral half of surface in some of questionable nonbers of germs." (Shiner and Shrock, 1944, page 667) Ulriohia ccnradi Jones (plate 2, figure 7) Carapace semioval in lateral view; greatest height in the center; straight hinge line, free nargin surrounded by a false border; blunt node in center of posterior half near dorsal, sharper node in center of anterior: reticulated surface. Length, 0.65 -., height, 0.40 -. Bare in well cuttings. ‘ This speoinen he been cornered with the description and plates by Warthin, 1934, page 213 (plate 1, figure 10) and agrees in every respect. Ulrichia mills Warthin Carapace ssnieval in lateral view; greatest hciylt just posterior to the center; anterior and sharper and higher: hinge line straight; false border around free nrgin with a thin carina that ferns a nearly perfect semicircle; two nodes near dorsal nargin in the center of the valve; surface finely reticulated. Length, 0.55 -., height 0.30 n. Bare in well cuttings. ‘l'his specinsn he been conparod with the description and plates by Warthin 1934, page 213 (plate 1, figure 11) and agrees in every respect. dense DIZYGOPLEUBL ulrich end Bassler 1923 , “Differs frcn xlccdcnella in having more or less distinct quadrilebation on valves, longer sulci, lid prominent lobes at and bearing brood pouch (probably posterior): dinorphic.” (Shiner and Shroch, 1944, page 679) 23 Disnopleura “51:22“ Warthin (plate 2,figure 9) Carapace subovate; greatest height near center of posterior half; greatest thickness in center of anterior half; anterior end pointed, posterior and more blunt; anterior and posterior sulci straight and equal in length; nedian sulcus curving slightly posteriorly, and dying out near mid-line; straight hinge line sloping antericrly; right valve overlaps left: Length, 1.50 m, height 0.70 In. Common in well cuttings. This specinen has been compared with the description and plates by Warthin 1934, page 210 (plate 1, figure 7) and agrees in every respect. Disncplsura cblgg: Warthin (plate 2, figure a) Carapace suboblong in lateral _ view; greatest height in center of posterior half; anterior and posterior ends equally rounded: posterior sulcus curving anteriorly; nsdian sulcus broad dying out near nidclinel anterior sulcus curving posteriorly. Length, 0.60 sn., height, 0.50 m. Gown in well cuttings. ‘ this specimen has been ccnparcd with the description and plates by Iarthin 1934, page 211 (plate 1, figure 6) and agrees in every respect. Diszgcplsura variant "A” (plate, 2. figures 10-11) Carapace subovate: greatest height near center of posterior half; greatest thickness in anterior half: anterior and pointed and posterior end more blunt. interior and posterior sulci straight but slightly slanting posteriorly; snall anterior node and large posterior node: nedian sulcus deep and straight to nid-line thal curved sharply posteriorly; straight hinge line with one posterior tooth: right valve slightly larger than left. Length, 0.70 n., height, 0.30 -. Bare in well cuttings. 24 Genus POLOIRLIA Gurich 1006 ”Apparently similar to Octonaria, but the border of the valve also bears a ridge. 1 semicircular Incision at the anterior end of the right valve, into which an extension of the left valve i'its.‘I (Bassler and Kellstt, 1934, page 37) Feloniella cfllata Warthin (plate 1, figure 3) Carapace suboblong in lateral view; greatest height in center of posterior half: anterior and higher and sharper, posterior end broadly rounded; posterior sulcus is straight to the aid-line then curves antericrly, and becomes narrow as it Joins the anterior sulcus; median sulcus triangular ending about mid-line. Length, 0.90 use, height, 0.50 m. Canon in well cuttings. This specinen has been compared with the description and plates by warthin, page 212 (plate 1, figure 9) and agrees in every respect. Poloniella variant "A” (plate 1, figures 1-2) This specimen is his LPoloniella cingglata encopt that the anterior end is more rounded; the median sulcus extending below the laid-line swings posteriorly and has a rather large swelling anteriorly. Length, 1.40 m, height, 0.60 In. Common in well cuttings. Genus ELLLIBLLL Ulrich 1691 ' ”Carapace with broad. sulcus and very coarsely reticulate surface which. rises to greatest height in anterodorsal quarter; thick double .border." (Shiner and Shrook, 1944, page 665) helliellshellimcte vsn Pelt ’ Carapace senioval in lateral view: greatest height is Just posterior to center; ends smoothly rounded: subtriangular median sulcus; hinge line 25 straight 3 surface coarsely reticulated: Length 0.65 1:11., height 0.40 m. Rare in well cuttings. - This specimen has been compared with the description and plates by Werthin, 1934, page 208 (plate 1, figure 2) and agrees in every respect. sellielle variant “a" ’ Carapace senioval in~lateral view; greatest height just posterior to center; ends snoothly rounded; weak sulcus just anterior to center; hinge line straight; blunt posterior spine just below laid-lino; surface coarsely reticu- lated. Length, 0.85 nn., height, 0.50 m. Bare in well cuttings. Genus BUPIIL corysll end nelhin 1936 -"Carapace subovate; dorsal margin straight; ventral nrgin convex; ends rounded, anterior and with a backward swing. Surface is orna- nented by two anterior spines and a posterior ridge, paralleling the posterior nargin. Snell papilla-like spines may or may not be pre- sent on the and margins. Contact of valves rabetted; right valve larger than left." (Coryell and Malhin, 1936, page 8) Mine “page.“ Coryell and Ialkin (plate 3, figures 14-15) Carapace subovate; greatest height and greatest thickness near center of valve; anterior and sharper than posterior end; straight hinge line sloping antericrly} right valve overlaps left; two anterior spines and a high sharp posterior flange: surface very finely reticulated with a snooth mscls spot in center of valve. Length, 0.90 m, height, 0.40 ea. Bare in well cuttings. This specimen has been compared with the description and plates by Coryell and lalkin, 1936, page 9, mid plate on page 13, figure 21, and agrees in every respect except for a prominent insole soar in the center of the valve. Bufina elongata variant ”i' This specimen is the sales as Bufina 3135: except that it is more ovate. Length, 0.65-u, height, 0.55 n. Rare in well cuttings 26 Genus EOEDEIIIA Jones and Hell less ”Straight-backed, subovate, rather obese shells with two subventral to dorsal sulci inclcsing a rounded median lobe; other lobes broadly convex; free margins with narrow border; dimorphic, with ventro- posterior, swollen, well defined brood pouchese' (Shiner and Shrock, 19“, page 675) . chedenia sussexensis Jones and Hell (plate 3, figure 12) Carapace subovate; greatest height near center; greatest thickness in the anterior end: anterior end“ sharper than the broadly rounded posterior end: hinge line is concave; fine carina arcmd free margin: median sulcus curving posteriorly: surface finely reticulated 3 Length, 1. 50 mm, height, 0.50 n. Bare in well cuttings. I this specimen has been compared with the description and plates by Shiner and Shrock, page 615 (plate 283, figure 40) and agrees with their abbreviated description. However, Shiner and Shrock figure incomplete specimens and some doubt exists as to whether structures present in the Traverse specimens exist in the specimen of Jones and Hell. Furthermore the stratigraphic horizon for their specimens are from Lower Devonian beds. Genus MEDIA lioGoy 1844 ”shell subtriangular or rhonbcidal, with greatest height near niddle: inequivalved; narrowly rounded anteriorly and pointed posteriorly; generally moth: dorsal margin rather strongly con- vex; hingenent fornsd by a groove in each of interlocking valves: over 200 species, some of which my belong to BAIRDOPPILLTA Coryell, Sample and Jennings 1955.' (Shiner m, page 683) . nun. variant “A" (plate 2, figure 12) Carapace subtriangular; greatest height’and greatest thickness near center of valves anterior end sharper than posterior and; right valve overlaps left; surface moth. Length, 1.30 mm, height, 0.80 us. Here in well cuttings. 27 Bairdia variant '3' Carapace elongated: greatest height near center of valve 3 anterior end pointed, posterior end blunt; hinge line straight; right valve overlaps left: surface smooth. Length, 1.00 m, height 0.60 m. Bare in well cuttings. Bairdia variant ”0" Carapace subtriangulars greatest height in center of valve 3 greatest thickness Just posterior to center: posterior end pointed Just above mid-line: surface smooth. Length, 1.50 m., height, 1.00 n. Bare in well cuttings. Genus $81011le Ulrich 1891' ”Carapace snall, rhonboidalz valves thick, right overlapping left except in posterior half of convex dorsal edge: surface of valves striate, except along edges where it is smooth; sharply defined narrow or rounded pit.” (Shiner and Shrock, 1944, page 687.) - ‘ . mulina variant ”A” A single specinen was assigned to this genus Mbilina by a nenber of the staff of the U. 8. national unsoun, (personal communication). The specimen was found in the Campbell lo. 1 well, 125 feet below the surface in the Killisns nenber of the traverse Fernation. 28 Genus renumonlcm Coryell and mum 1936 The genotype of Pondcrodictfl bispinulata was erected on gytherclla bispinulatus Stewart, 1927, page 60, who obtained her material from the type locality of the Silica shale near Sylvania, Ohio. Coryell and Halkin later made the specie szherella bispinulata the genotype of PonderodictE. Al- though we do not have any specimens of Ponderodictya bispinulata from the type locality we have specimens of that specie from a shale member in a well located in Wayne County, Michigan, which were studied and identified by Dr. Virginia Kline. Our specimens have been compared with these and are regarded as specifically identical. "Carapace ovate; dorsal margin convex; ventral margin straight with central sinuosity in ventral contact; convex at extremities. Posterior margin rounded; anterior margin broadly rounded with backward swing, and lower than posterior. Left valve overlaps right on all margins, with overlap most pronounced ventrally. A ridge near the margin of the right valve fits into a groove in the left. Surface of valve rcticulate, with a less ornamented spot Just anterior to the center of the valve. interior and posterior without reticulations. Two small nodes or spines, the ventral one more prominent, project near the posterior end from the surface of the convexity, at the crest of the posterior dorsal and posterior ventral slopes. Near the anterior end is a low, non-reticulate, curved ridge, more prominent in the right valve and in some specimens apparently lacking in the left. Greatest height is located about one third of the length from the posterior end, with convexity greatest near the center of the posterior half of the valve.“ (Coryell and Malkin, 1936, page 16) l'he generic description applies to the specimens obtained from the Traverse Formtion during the course of this investigation. To the generic description the author would add the following remarks: Not having had the opportunity to study the type material of Ponderodictya bispinulata (Stewart), the identification is based entirely on descriptions and illustrations in the article by Coryell and Malkin, 1936. It is difficult to Judge the general appearance of Coryell and Malkin's plesiotype Ponderodicm bispyulata from the illustrations. Such features as size, 29 length of spines, and development of the flange can only be approximated. Judging alone from Corycll and Malkin's descriptions there seems to be little doubt that the genotype is represented in the Traverse Formation of nichigan. The majority of the forms studied in this investigation do not completely satisfy this description. Variations from the normal, on the other hand, are abundant. Therefore, the writer has made up a preliminary series of groups which vary in minor characteristics from the genotype as well as from each other. These variations from the type are described as variants. The variants differ chiefly in size, ornamentation, in development of the anterior flange and the posterior spines. All specimens have the some general outline, same reticulation, same muscle spot, but some leek almost entirely the posterior flange, or the anterior spines, or both. Typical examples of these variants are described below as variants ”A” to '3'. Ponderodictn bispinulata (3......) variant ”A” (plate 3, figures 14-3) is taken as identical with n. plosiotype of Ponderodigz: bispinulata described by Goryell and llalkin as well as the forms identified by Dr. Kline. Ponderodietza bispinulatg (Stewart) variant '3' differs from the variant '1' in the absence of a posterior spine. In other respects it agrees because there is a strong anterior flange and strong overlap of the valves. There is also an unornamented spot near the center of the valve. Ponderedictya bispinulata (Stewart) variant "6" (plate 3, figures 4-5) resemble variant '8' in the presence of only, one spine-ventrally low on the posterior end, and a weak development of nanterior flange. In variant '0' the flange is reduced almost to an elliptical node. 30 Ponderodictya bispinulata (Stewart) variant 'D" (plate 3, figure 8) differs from ”A", “3" and "c'' in the greatly reduced posterior spine and anterior flange. ln'this specimen there is a weak, narrow, semi-lunar ridge at the posterior end. This form is the most semen of the variants and is found throughout the cstracoda sons. genderodictn bispinulata (Stewart) variant ”E“ (plate 3, figure 6) resembles 'D' in the presence of a strong posterior spine near the venter, and a rounded node near the dorsum and a moderate, well-developed anterior flulge. It differs markedly in the absence of characteristic reticulation and also in in the proportion of length to height of carapace, variant ”B” being propor- tionately shorter. It is possible that these weak reticulated forms may be partially exfoliated specimens. These forms are women near the top of the Traverse ostracode acne and stratigraphically higher than those assigned to variant '3' which is more common near the base of the zone. . fendercdietya bispinulata (Stewart) variant 'F' (plate 3, figure 7) is the same as “3“ except it has a snmll, sharp, posterior spine and no anterior flange. Ponderodictn bispinulata (Stewart) variant 'G' lacks all ems-sn- tation except a low, rounded, anterior flange. Ponderodicm bispinulata (Stewart) variant "H" (plate 5, figure 9) has a weakly developed spine and flange and is very small in size. It is probably a molt of a young cstracoda. 31 Genus JENNINGSIIA (Van‘Pelt 1933) "carapace subreniforn; mg. 1n. straight. Surface of valveeovered with fine ridges diverging from a median line. These ridges are connected by cross bars at intervals slightly larger than the space between two ridges, thus producing in effect rows or elongate reticulaticns. In the center of the valve is a snall circular pit. Right valve overlaps the left of free nrgins.‘ (Goryell and Halkin, 1936, page 19) J ' sinadcatenulata (Van Pelt) (plate 1, figure 4) Carapace subreniforn; hinge line straight 3 surface covered with fine ridges which are connected by cross bars giving the effect of rows of elongated reticulation” a. snall circular pit in the center of the valve; right valve overlaps left. Length, 0.80 m, height 0.55 In. Bare in well cuttings, not found in outcrops. This specinen has been compared with the description and plates by Goryell'and mum, 1935, page 19 (plate on page 12, fipire as) and agrees in every respect. . Genus QUASILLIIES Coryell manna: 1936 ”Carapace subovate to rhonboidal; hinge line straight. Ventral nrgin straiynt to gently convex. Right valve larger then left, with a grooved contact to receive the left valve. Surface of valves is marked by fine longitudinal ridges and grooves, bifurcating along a median line, and diverging slightly anteriorly. A less orna- nmted median spot is usually discernible. Posterior convexity is generally elevated into a ridge-like surface at the crest of the steep posterior slope. a spine projects forward from the anterior ventral region, at the crest of the anterior slope.‘I (Coryell and lalkin, 1930, page 18) - Quasillites suboblims Swarts and 034.1 Carapace subrhonboidal; greatest height in center of posterior half; greatest thickness in anterior half; anterior end is sharp and posterior and blunt; hinge line straight: right valve overlaps left: blunt antero- ventral spine; surface is covered with ”fingerprint" ornamtation except for 32 a smooth median spot. Length, 1.00 m, height, 0.50 nus. Common in well cuttings. Quasillites ornatus Swarts and Oriel Carapace subovate; greatest height is anterior to center; anterior end blunt, posterior end sharp; hinge line slightly curved; right valve slightly larger then left valve 3 blunt sntero-ventral spine; surface has “fingerprint” ornamentation except for smooth ‘median spot. Length, 1.00 -., height, 0.60-n. Common in well cuttings. ' Quasillites lobatus Swarts and Oriel Carapace subrhonboidalz greatest height posterior to center; greatest thickness in the anterior half; anterior and sharp; posterior and blunt; hinge line straight sloping anteriorly; right valve overlaps left; blunt antero- ventral spine 3 surface ornanented with "fingerprint” ornamentation except for clear nodien spot. Length, 1.00 m... hsight, 0.50 in. Com in well cuttings. In the writer's. opinion, these three species differ only in minor details and should be given the rank of variants, because the variations between then are consensurate with the variations between forns of Ponderodictfl bispinulata previously described on page 29. guasillites binodosus Swarts and Oriel (plate 1, figure 5) Carapace subquadratc; greatest height Just posterior of center; greatest thickness in anterior half; anterior end sharper; posterior end blunter; hinge line straight sloping anteriorly; right valve slightly over- lapping the left; blunt antero-ventral spine 3 surface is covered with reticu- lations arranged in rows except for a smooth, median spot. Length, 0.80 -., height, 0.35 n. Cannon in well cuttings. . The above specimens have been oonpared with the descriptions and plates by Swarts and Oriel, 1948, pages 556 to 559 and agree in every respect. 33 Genus SPINOVDIA Goryell and flalkin, 1936 'Carapace cytherelloid: hinge straight, channeled. Right valve.overlaps left, with grooved contact in right valve to receive the ridge of the smaller left valve. Surface marked by longitudinal ridges. in anterior ventral spine projects forward from the crest of the anterior slope of the convexity. a median spot free from ornamentation is present near the center of the valve.” (Coryell and halkin, 1936, page 17) Spinovina distributa Coryell and halkin Carapace ovate; greatest height anterior half; greatest thickness in the anterior half; anterior and more bluntly rounded than posterior end; hinge line straight; right valve overlaps left valve 3 blunt anteroventral spine and a weak posterior flange; surface covered with I'fingerprint" orna- nentation. Length, 1.10 m., height, 0.65 an. Rare in well cuttings. This specimen has been compared with descriptions and illustrations by 'Coryell and Malkin, 1936, page 17. The fine ornamentation, ”fingerprint” feature, eonld net, however, be directly compared with their‘illustrations. Genus EUGLIPBELLL Warthin 193a . ”Carapace subtriangular in lateral view, greatest height in posterior half; hinge line straight, inconspicuous; each valve bears a c-shaped carina opening anteriorly; anterior end spinese.‘ (Shiner and Shrock, 1944, page 281) Euglyphella siggidalis warthln (plate 1, figure a) ‘Carapace subtriangular: greatest'height in center of posterior half; greatest thickness in center of valve; anterior end sharp and high: posterior end broadly rounded; hinge line straight; right valve slightly smaller than the left; each valve has sharp ”0" shaped carina, the opening of the 'C" is anterior; anterior and has small spines; Length, 0.90 111111., height, 0.60 m. Bare in well cuttings. 34: This specimen has been compared with the description and plates by Warthin, 1954, page 220 (plate 1, figure 21) and agrees in every respect. Egglmella sigmoidalis Warthin variant "1" This specimen differs from.Euglyphella sigmoidalis (s.s.) in that the anterior end is more blunt and lacks spines. Length, 0.75 mm., height, 0.55 In. Common in well cuttings throughout the cstracoda sons. Eglflella sigmoidalis Warthin, variant 'B" This specimen differs from.Euglyphella sigmoidalis (s.s.) in that it has a small projection anteriorly and lacks spines. Length, 1.00 mm, height, 0.50 mm. Bare in well cuttings. Genus HYPEASMOPHORA Van P011: 1933 ”Valve with reticulate surface and central pit, but lacks the mar inal ridge of Amphissitee." (Bassler and Kellett, 1934, page 31 - musnphora textiligera Carapace subovate; greatest height in center of posterior half; hinge line curving, ends smoothly rounded, posterior end lower and blunter: coarse irregular reticulation, with a deep pit near the center; right valve overlaps the left. Length, 0.50 lame, height 0.25 In. Bare in well cuttingse Genus OCTONARIA Jones-1887 ”Similar to Thligsurella, but distinguished by tendency of left valve.te overlap r g , an y having surface of valves raised into a thin spiral or ringlibe ridge, which in more typical form resembles the figure "8". (Shiner and Shrock, 1944, page 682) Octonaria variant 3A” (plate 1, figures 7 and 11) Carapace reniform; .greatest height posterior to center: greatest 35 thickness in center of anterior half; anterior end sharper than posterior; hinge line straight; surface ornamnted with deep pits and fine longitudinal striations. Length, 1.00 11-1., height 0.50 ass. Colman in well cuttings. A number of specimens that differ from variant ”A” only in the amount of sculpturing on the valves were found in this investigation. Some specimens are sculptured only on one valve and others are weakly sculptured on both valves. (plate 1, figures 8-9-10 show these variations) Genus THLIPSURA Jones and Hell 1869 “Valves convex with right everlapping left and with region bordering anterior margin depressed to form well defined sunken area with one to two furrows opening from this area and exten- ding baok for some distance.“ (Shiner and Shreck, 1944, page 681) . Carapace subovate; greatest height near center; greatest thickness near posterior: anterior end sharp, posterior blunt; hinge line straight; right valve overlaps left: small posterior flange. Length, 1.00 m., height, 0.50 n. Bare in well cuttings. (plate 1, figures 13-14;) PHYLUII BRYOZOA Genus ACROGENIA Hall 1888 ' ”Seycented, arising from cylindrical rootlets, two seg- ments from truncated ends of preceding one, each obconieal and striated at. base, later becoming flattened and bearing apertures in linear series, separated by ridges, largest in urginal row: lunaria prominent." (Shiner and Shrock, 1944, page 270) - Brycsoan icroflia variant '1' is a tapered cylindrical form, that has long sigmoid striations which give an appearance of a rifled bullet. The smaller end averages .66 mm. in diameter and has a shallow conic projection. . 1, . . l . .rg ,. O . . . v.. . . . I. a . I . A A ‘ e o. i . . I ' N u; . . . , , . 1 vv 0 4 . . O .. a a _ .. . . . . . O. l . . e u t .. I I, . OI I ‘ v n A W l . . ~ v \ J. . ‘I o . a .m n , O. . _ Kl . -. a .. . , A! . - u . . I. v O u . . Vs) . 4 . .. .lv e . O . a . , . o . . a . . . . ‘ n D e .. . r '4 I A 1 ea .. . u < .4 I r: . a v (V. , . c . ‘_ o . If. .f. I . I .9, V v u e.. — . v I I a n . . I. . . u L .1 4 i .v. w . «m I . , v; e m 0 ., . v v . e I.» I .L . n . r. . . A 9. 1a ‘. . " . . . . ‘ _ . O I. s a..-.- 36 The larger end averages .70 m. in diameter and has a shallow conic depression. The average overall length of the specimen is 1.3 m. (plate 1, figure 15). It is apparent that the conic projection of one unit‘fits into the conic dc- prcssion of another unit in the growth of the aninnl. (plate 1, figure 16) On the projection and depression ends there are concentric growth rings and fine radial striae. Common in well cuttings. CHAROPHYTA Groves J., 1933 ”Charophyta are small bushy plants ranging from about ton on. to 60-cn. in height. They occur abundantly in quiet, clear, fresh- water bodies, like ponds, ditches, and lakes, and are distributed widely throughout the world. The outstanding characteristics of the group are the male and female reproductive organs, termed the antheridia and oogonia, respectively, and the whorled lateral branches on vhich the organs are borne. Some species secrete calcium carbonate and are large contributors to fresh water line- stones. ~ Fossil Charophyta are exclusively oogonia. Vegetative parts are seldon preserved.” (Shiner and Shrock, 1944, page 712) Troehiliscus, Karpinsky variant ”A” (plate 1, figure 12) Calcificd oogonia with nine spiralling striae beginning in a cen- tral pit. Diameter, 0.50 m. Found only in wells and outcrops in Cheboygan County. This specimen has been compared with the description given by Shiner and Shrock, 19“, on page 113. . The presence of Trochiliscus in the Traverse Formtion, ordinarily re- garded as exclusively marine, may be explained either by the possible prox- imity of these sediments to a shoreline, or by rafting far out to sea. S'l INTERPRETATIOI 0F CROSS SECTIONS Map 3, page 39, shows position of Cross Sections A study of the cross section i-I fron Defiance County, Ohio, northeast, to Lanbton County, Ontario (figure 4, page 52) , shows that the ostracod zone: a. lies in the lower half of the Traverse Formation b. reflects the Michigan basin structure I c. reflects the St. Clair structure d. increases in thickness as it enters the deeper part of the hichigan basin 1 study of the cross sectien A-B from Defiance County, Ohio, north, to Perron Point Shale outcrop at Black Lake, Choboygan County, Michigan (figure 5 in pocket) shows that the ostracod zone: a. lies in the lower half of the Traverse Formation b. reflects the Michigan basin structure . c. reflects the structure of the Howell anticlinc d. reflects the West Branch structure e. increases in thickness as it enters the deeper part of the Michigan basin This cross section also shows that the Silica shale of northwest Ohio appears to be stratigraphically lower than the Ferron Point shale of the Black Lake locality. 38 A study of Cross Section.C-D, Chcboygan County, Michigan, southeast to Lanbton County, Ontario (figure 6, page 53) shows that the ostracod sons: a. lies in the lower half of the Traverse Formation b. reflects the Michigan Basin structure c. reflects the St. Clair structure d. increases in thickness as it enters the deeper part of the Michigan MI no A study of Cross Section s-r from Wayne County, northwest to Montcaln County shove (figure 7, page 54) that the ostracod zone: a. lies in the lower half of the Traverse Formation b. reflects the lichigan Basin structure o. reflects the pitch of the howell structure because it is approximately parallel to the axis. A study of Cross Section 6+3 from Iosco Township, Livingston County, northeast to Hartland Township, Livingston county (figure a, page 55) shows that the estracod sons: - . a. lies in the lower half of the Traverse Formation b. reflects the reverse dip of the Howell Structure because it is taken approximately perpendicular to the strike. MP3 MICHIGAN DEPARTMENT OF CONSERVATION , GEOLOGICAL SURVEY DIVISION so“ I I.“ m 0 INDEX MAP SHOWING POSITIONS OF' CROSS SECTTONS \ DOMINION OF CANADA .‘ CH4~~£L ( 0 i o ' ,w. , - , I 1° crtso 4- t ’0‘ ( a“ C e“ ./ ' 3 PRESOUE ISLE [d / cmmvou . xx [x/ P O 3 Arum orsmoI nchv ALPENA t . t x * mm 9 / \ 0 , V mung all us“ ran-FORD 05C A ALCONA ' um: I / g mum: I \ c . ,1. 15m wtxronn IMISSAUKI noscowom o MAN uosco no / b o ARENAC I \ NASON LAKE 05cc0LA CLARE GLAOVIIN *9 z /' t a“? HURON . I I; I oczANA uscosn IsAsELLA MIDLAND 1 Names COLA I “’5 ILAc ' SAC-l w ‘ “mural“ 1 \ uusmm E sumo “fl \ / )(\ KENT othsEL LAPEER SAI . ‘. 0mm IONIA (L M E CW" V l “ I ' MACON OAKLAND . ALLEGAII BARRY EATON ING 0“ i LAKE 57‘ can I ”‘ ”a“ NALANAZ CALHOUN JACKSON ASHY AN NAVN: I : :CANADA I .' ST / CASS sNANcH HILLSDALE NONRot -_ , JOSEPH ‘_/‘ LA [(5 IN D I A N A 1r-—-" '—'"_ '-' ERIE \D 40 DISTRIBUTIOI CHART 01" OSTRACODA AND THE BRYOZOAK. ACROGENIA. III THE TRAVERSE FORMATION This stratigraphic distribution chart (figure 9 in pocket) shows the vertical range and frequency of cstracoda and bryozoa within the Traverse Pomtion, from Black Lake outcrop, Cheboygan County, Michigan to well lilo. 13 in Lanbton County, Ontario. Twenty-two genera of cstracoda, one bryczosn genus and a single plant, were found and determined. Only the most abundant genera were used in as much as they give a true picture of the stratigraphic distribution. The _ genera are listed below: Ostraooda -- Amphissites Bairdia Ctenobolbina Ctenoloculina Diaygopleura Euglyphella Jenningsina Octonaria Poloniella Ponderodictya Quasillites Spinovina Bryosoan -- Acrogenia This chart shows a general restriction of genera to the lower half of the Traverse Formtion. There is an exceptional occurrence of five ostra- coda in the top fifty feet in well S.P. 10610, in Huron County. It is pos- sible that the samples from this well my have been mic-labeled, as they represent the only case where cstracoda, collected from sixty-six wells, were found near the top of the Traverse Formation. The distribution chart of cstracoda shows an increase in thickness of the zone as it enters the deeper part of the hichigan basin. 41 SUMMARY Together, all cross sections show that the ostracod zone: ‘e be 0e d. lies in the lower half of the Traverse Formation reflects the Michigan basin structure reflects structures in lower formations increases in thickness as it enters the deeper part of the lichigan basin the Silica shale of northwest Ohio appears to be stratigraphically lower than the Ferron Point shale of the Black Lake locality. A. B. C. D. E. P. G. H. I. J. K. 42 00110 L113 1038 There is an ostracode zone within the Traverse Formation. The cstracoda zone lies in the lower half of the Traverse Formation. The ostracodc zone follows the synolinal Michigan basin and reflects structures in deeper formations. This zone becomes thicker in the deeper parts of the basin. Ponderodictya, Quasillites, Euglyphella, Dizygopleura, Poloniella, and Octonaria are abundant in this zone. Pondcrodictn has a long vertical range in this zone but is more abun- dant near the base. guasillites, Euglyphella, Dizygoplcura, Poloniella, and Octonaria are found throughout the zone but are more abundant just above the zone of concentration of Ponderodicti. Bryozoan icrogenia is comon in this zone. Tcntaculites and crinoids are found along with the cstracoda. Ponderodictya, Poloniella, Octonaria and Quasillitcs are common in the Upper Blue shale of the Gravel Point from the Bell quarry. Pondcrodictya, Poloniella, Octonaria, Euglflhella, Ctenobolbina, Ctenolcculina and Bryozosn Acroggnia are semen in the Ferron Point shale from Black Lake locality. ' Ostraooda do more abundant in shale than limestone. This could be due to mechanical concentration. In the harder nterial, cstracoda are broken into fragments, whereas'in shale which is soft, the cstracoda are not broken and better specimens are obtained. 43 BIBLIOGRAPHY Bassler, R. S. and Kellctt (1934), ”Bibliographic Index of Paleozoic Ostraooda”, 500 pages. . Coryell, a. l. and.Malkin, D. 3., (1936), "Some Hamilton Ostraoodes from irkona Ontario”, American Museum of Novitates, No. 891, pages 1-20. Glaessner, M. F., (1945), ”Principles of Micropalcontology", pages 12-17. Kelly, Dr. In. i., (1950), Personal Communication. _ Shiner and Shrock, (1944), "Index Fossils of north America”, pages 660-691. Swlnn, n. 3., (1947), "The Favosites Alpenensis Lineage in the Middle Devonian Traverse Group of I'lichigan", Contributions from the Museum of Paleontology, University of Michigan 71, Article 9, pages 256-239. Swarts, F. 11., and Uriel, S. 8., (194:8), ”Ostraooda from Middle Devonian Windosl Beds in Western New Xork", Journal of Paleontology, Vol. 22, No. 5, pages 541-686 - Warthin, A. 8. Jr., (1934), "Common Ostraooda of the Traverse Group", Contributions from the Museum of Paleontology, University of Michigan, Vol. Iv, pages 206-228. Warthin, i. 8. Jr., (1946), "Type Invertebrate Fossils of north America - (Devonian)", Wagner Frce_1nstitute of Science, pages l-195. Figure 1 Figure 2 Figure, 3 Figure 4 Figure 6 Figure 6 Figure ‘I Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 44 EXPLANATION OF PLATE I All specimens are magnified 18 diameters. Footage refers to the depth below intrin- Traverse contact at which the fossil cstracoda was found. Poloniella variant “A” . . . . . Right valve 3. P. No. 13922, 260 feet Poloniella variant 'A' . . . . . DcrsaI view So Pe NGe 13922, 260 fOOt Poloniella cigglata Werthin. . Right valve 8e Pe Has 13922. 270 feet Jenningsina catenulata (Van Pelt). va ve Canada No. 12, 200 feet Quasillites binodosus Swartz and Right valve Canada No. 12, 206 feet Euglfiphella sigmoidalis Warthin. R s W” Black Lake outcrop Octonaria variult ”A”. . . . . . valve . l S. P. No. 13841, 246 feet Octonaria variants from “A”. . . rare valve Se Pe IOe 13841, 250 t.°t Octonaria variants from "i'. . . valve Black Lake outcrop . Octonaria variants from "A”. . . valve Black Lake outcrop Q ‘ DetonQS1‘ Tari‘nt 'A'e e e e e e Right valve - - Canada lo. 12, 230 feet Oriel Charophyta Trochiliscus Karpinsky. . . e 0e 11933, ’5 I.“ Page 24 24 24 31 32 33 35 35 35 36 Figure 13 Figure 14 Figure 15 Figure 16 45 Thlisura........ Ekvalve Black Lake outcrop ThlipfiurC1e e e e e e e e DorsaI view Black Lake outcrop Bryozcsn Acrogenia. . . . Side view 8. P. No. 10510, 220 feet Bryozoan iorogcnia. . . . Side view 3. P. IO. 14837, 140 feet Page .35 .35 .36 36 l3 PLATE - l /‘ ’1 I. It Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure 10 11 47 EXPLANATION OF PLATE II All specimens are magnified 18 diameters. Footage refers to the depth below intrin- Traversc contact at which the fossil cstracoda was found. HOllinell‘ varifint "A'e e e e e e e e e e e Wm . - Canada No. 12, 110 feet CtCnObOIbin‘ Variant "E”e e e e e e e e e e m . . Canada No. 12, 110 feet CtODObOIbinfl variflnt “C"e e e e e e e e e e Left vaIve A . Canada lo. 12, 100 feet H0111n0115 tr1°0111n3 V‘n Pelte c e e e e e n v. Canada No. 90, 150 feet CtCDObOIbin‘ Variant “B”. e e e e e e e e e n V. . . Canada No. 13, 180 feet CtOnObOIbin‘ variant ".e e e e e e e e e e W W I - Canada No. 12, 100 feet Ulrichia conradi Jones. . . . . . . . . . . vaIve ' Canada No. 12, 130 feet Eizggpleura oblong: Worthin. . . . . . . . vs vs 3. P. No. 11001, 270 feet Dizygopleura e_uglyphea Warthin. . . . . . . Le va ve 8.13. No. 11001, 270 feet D130lOqu1ut'A.eeeeeeeeee va V. - - 3. P. NO. 13922, 250 £001: Dilygoplcira v‘rilnt .‘.e e e e e e e e e e Darla! 5.!" . . SeVPe Re. 13922, 260 fCOt B‘irdi‘ varifint "A. 0 e e e e e e e e c e e “valve - - Black Lake outcrop Page . 21 PLATE - 2 131‘, 8 / IO M :2 48 Figure 1 Figure 2 Figure 3 Figure 4 Figure 6 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 49 EXPLANATION OF PLATE III All specimens are neglified 18 diameters. Footage refers to the depth below intrin- Traverse contact at which the fossil cstracoda was found. Pondcrodictya bispinulata Right valve 8e Pa Has 138‘1, 245 fCOt Pondcrodictya bispinulata Dorsal view 8. P. No. 13841, 246 feet Ponderodictys. bispinulata Left vaIve S..P. No. 13841, 246 feet Pondcrodicjya bispinu lata Right valve (Stewart) variant (Stewart) variant (Stewart) variant (Stewart) variant 5. F. No. 13028, 275 feet ‘ Pondcrodict bispinulata BorsaI How Se Pa NOe 130283 275 fbet Pondcrodictya bis pinulata Right valve 8. P. No. 13702, 216 feet Pcnderodicty: bispinulata R g vs vs 8. P. No. 13702, 215 feet Pondcrodict}: bispinulata High} V3170 3e Pe No. 11001, 280 tbOt Pondcrodict bispinulata Left vaIve Ohio No. l, 40 feet Len vaIve (Stewart) variant (Stewart) variant (Stewart) variant (Stewart) variant (Stewart) variant ”AI. "A”e IA“. ”cl no. I?" “D” . "H”. Ctenoloculina picatricosa (Warthin). . . . . . . Canada No. 12, 210 feet Ct__e_noloculina cicatricosa (Warthin) variant “A”. VentraTv'liw Canada No. 12, 160 feet Kloedenia susscxensis? Jones and Roll. . . . . . valve Black Lake outcrop Page . 29 50 Page F18”. 18 W'sitCQ lubquadratul ("hi“)e e e e e e e e e e e e e e 21 Figure 1a Figure 15 va ve Canada No. 12, 226 feet Burn.’ Olanfi‘t‘ comll and mum e e e e e e e e e e e e e 25 7 Left va ve 8. P. No. 13025, 230 feet Mina. Clongflta. Coryoll md “film e e e e e e e e e e e e e 25 Dorsal view Se Pa NOe 13025, 230 feet PLATE - 3 Figure 4 I | {SOUNTY,ONTARIO- IIOOI Figure 6 l2 ‘0 HORIZONTAL VERTICAL SCALE l- (INCH 8 8 MILES IINCHIIOOFEET O FP'OO ”200 J '300 Lb4oo “”500 l ’600 hr7oo ”BOO D E CAMPAU |950 Floors 7 I::54 ; 7227 2::I 1W0 ~~mo H—zoo ”_____,__———4 ~-3oo p———”“'————d / ~+4oo : Hr-SOO .L__1 ~ D.E.CAMPAU |950 1 Figure 8 0mm. 2a)“; m a puma 00. u xuz. _ .222: 34.: n . :02: 4323on meqom ooej 20:32.3 mmozao con: .\ WZON 000 Frame oomj 00.3 Oil mmem 3:524 com. do 53. mm: 300. x o >HZDOQ 20Fm02_>_.._ .12; o2<4hm