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ABSTRACT

PALYNOLOGY AND PALEOECOLOGY OF THE
MIOCENE SUCKER CREEK FLORA FROM
THE OREGON - IDAHO BOUNDARY

BY

Ralph E. Taggart

Three geological sections in the Sucker Creek
area of Malheur County, Oregon and Owyhee County, Idaho
were measured and sampled for palynological analysis.
The study sections comprise approximately 400 feet of
composite section representing a sedimentary interval
during which most or all of the macrofossil-bearing beds
of the Sucker Creek flora were deposited. Although the
sites of the study sections are included in the mapped
extent of the Sucker Creek Formation, the sediments are
not correlatable with those of the type section for the
formation. The plant-bearing sediments appear to be
somewhat older than the Sucker Creek type section and it
is suggested that the Sucker Creek Formation, as mapped,
is in need of revision. The floristic and faunal evidence
suggests a late Miocene age for the Formation as a whole
and, at present, late Barstovian is the most precise age

determination which can be made.

Ralph E. Taggart

The pollen profiles from the study sections suggest
two distinct episodes of vegetation development. The
beginning of the composite sequence is characterized by
an equilibrium between two major forest types, a mesic
deciduous forest, probably cool temperate in aspect,
occupying the lowlands of an inter-montane valley system
and a montane conifer forest on the adjacent uplands.

The lowlands were apparently well drained at the beginning
of the depositional interval but this situation was
followed by extensive impoundment of water, probably in
the form of ox-bow lakes. Infilling of the lake systems
with both organic and detrital sediments resulted in a
successional series involving marsh and swamp communities.
Distinct flood-plain communities were also in evidence at
this time.

Following this phase, a major shift in the pollen
record indicates a significant change in the nature of
the source vegetation. Many of the mesic deciduous genera
and all of the montane conifer genera disappear from the
record. The remaining pollen types suggest a comparatively
depauperate riparian forest in a region of predominantly
xeric aspect. It is postulated that this shift in vegeta—
tion types was due to an interaction of local and regional
factors, including destruction of the existing forest
Vegetation due to local volcanic activity, a regional
warming trend, possibly coupled with a decrease in thermal

equibility, and the decreasing rainfall brought about by the

Ralph E. Taggart

gradual uplift of the Cascades to the west. It is not
possible to determine, on the basis of data presently
available, whether this shift in vegetation dominance
was a pivotal one for the region or if it represents a
shorter term successional sequence or small-scale oscilla-
tion.

Several new microfossil records for the flora are des-

cribed including the alga Botryococcus, several new spores,

 

and pollen including a new Abies type, several new Pinus,

Podocarpus, Castanea, Mahonia, several Compositae,

 

 

Elaeagnus, Ilex, two Onagraceae, fiymphaea, Nyssa, Capri-

 

 

foliaceae, Pachysandra, and several unusual although

 

unidentified pollen and spore types.

PALYNOLOGY AND PALEOECOLOGY OF THE
MIOCENE SUCKER CREEK FLORA FROM

THE OREGON - IDAHO BOUNDARY

BY

1'
‘1

Ralph E? Taggart

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY
Department of Botany and Plant Pathology

1971,

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S at O. . v .5 C . C TV a D. 1 LL a

 

ACKNOWLEDGMENTS

Of the many individuals and institutions which
contributed in some way to the advancement of this study,
I would like to single out a small number for special
mention at this time. Foremost among these is Dr. Aureal
T. Cross, Professor of Botany and Plant Pathology and
Geology at Michigan State University. Dr. Cross, in
serving as major advisor for this dissertation, provided
encouragement and material assistance during all phases
of this study. His continual efforts over the past years,
both as an advisor and teacher have, above all else, pro-
vided the atmosphere and incentive that is indispensible
for graduate research. I would also like to extend my sin-
cere thanks to the members of my Guidance Committee, Dr.
William B. Drew, Dr. John H. Beaman, Dr. Stephen Stephenson
and Dr. Melinda Denton of the Department of Botany and Plant
Pathology and Dr. Robert L. Anstey of the Department of Geo-
logy, for their critical evaluation of this manuscript and
their efforts on behalf of my doctoral program. I would also
like to thank the many members of the Department of Botany
aand.Plant Pathology and the Department of Geology who

Iuaver failed to give of their time in providing advice and

ii

 

 

 

 

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assistance during various phases of this study. In this
regard I would particularly like to acknowledge the
assistance of Dr. Chilton Prouty of the Department of
Geology for his discussions of some of the stratigraphic
implications inherent in this study.

I was fortunate to receive generous financial
assistance from a number of sources. During the period
from September of 1967 through August of 1970 I studied
under the auspices of a Graduate Traineeship funded by
the National Aeronautics and Space Administration which
provided support for tuition, fees, and a monthly stipend.
The Department of Botany and Plant Pathology provided
support for the 1970-1971 academic year in the form of a
Teaching Assistantship. These sources of financial aid
removed the hardship of that aspect of graduate work and
I would like to express my appreciation.

During the Spring of 1971 I received two awards
whose proceeds were applied to defray the cost of prepar-
ing this manuscript. The first was a Distinguished Gradu-
ate Student Award provided by the Society of the Sigma Xi
and the second was the Ernst A. Bessey Graduate Student
.Award tendered annually by the Department of Botany and
IPlant Pathology. I feel honored to have received both of
these prizes.

Finally, I would like to express my deep thanks to

nu! wife Alison whose untiring encouragement and assistance

iii

stu-

 

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p is. ! “In:

provided the essential background that can make graduate

study a continuing adventure.

iv

TABLE OF CONTENTS

Page
ACKNOWLEDGEMENTS O O O O O 0 O O O O O O 0 ii
LIST OF FIGURES . . . . . . . . . . . . . vii

LIST OF PLATES . . . . . . . . . . . . . viii

Chapter

I. INTRODUCTION . . . . . . . . . . . 1
II 0 METHODS O O O O O O O C O 0 O C Q 6
Field Procedures . . . . . . . . . 6
Laboratory Procedures . . . . . . . 8
III 0 GEOLOGY O O O O O O O O O O O O 0 l7
Physiography . . . . . . . . . . 17
Structure . . . . . . . . . . . l8
Stratigraphy . . . . . . . . . . 19
IV. STRATIGRAPHIC PALYNOLOGY . . . . . . . 35
Valley Section . . . . . . . . . 35
Shortcut Section . . . . . . . . . 42
Rockville Section . . . . . . . . 46
Comparison of Study Sections . . . . . 49
V. PALEOECOLOGY . . . . . . . . . . . 53

Patterns of Vegetation Change
During Sucker Creek Time . . . . . 65
VI . SYSTEMATICS O O O O O O O O O O O O 84
Nomenclature . . . . . . . . . . 84
Systematic Descriptions . . . . . . 92

Page
LITERATURE CITED . . . . . . . . . . . . . 159
APPENDIX 0 O O O 0 O O O O O O O O O O O 165

PLATES . . . . . . . . . . . . . . . . 174

vi

 

 

 

LIST OF FIGURES

Figure Page

1. Outline map of the study area showing the

location of sites discussed in the text . . 3
2. Correlation chart of the Cenozoic formations

of eastern Oregon . . . . . . . . . . 21
3. Stratigigraphic terminology . . . . . . . 22
4. Generalized diagram of the rock units of

each of the study sections and the

proposed correlations . . . . . . . . 24
5. Relative frequency pollen and Spore profiles

from the Valley section . . . . . . . . 36
6. Relative frequency pollen and spore profiles

from the Upper Swamp Series in the Valley
section . . . . . . . . . . . . . 40

7. Relative frequency pollen and spore profiles
from the Shortcut section . . . . . . . 43
8. Relative frequency pollen and spore profiles

from the Rockville section . . . . . . . 47

9. A generalized ecological classification of
selected pollen types found in the
Sucker Creek sediments . . . . . . . . 59

10. A list of selected Sucker Creek macrofossil
genera and their occurrence in the upper
and lower portions of the composite
regional section . . . . . . . . . . 69

ll. Oligocene—Miocene temperature trends postu~
lated on the basis of (A) ecological
analysis (Axelrod and Bailey, 1969) and
(B) leaf morphology (Wolfe and Hopkins,
1967 . . . . . . . . . . . . . . 78

vii

LIST OF PLATES

A View of the valley system formed by the
rocks of the Rockville section . . .

A view of the Shortcut section . . . .
Figures 1 through 19 . . . . . . .
Figures 1 through 10 . . . . . . .
Figures 1 and 2 . . . . . . . . .
Figures 1 and 2 . . . . . . . . .
Figures 1 through 8. . . . . . . .
Figures 1 through 21 . . . . . . .
Figures 1 through 13 . . . . . . .
Figures 1 through 15 . . . . . . .
Figures 1 through 16 . . . . . . .

viii

Page

175
177
179
181
183
185
187
189
191
193

195

 

. lint.

CHAPTER I

INTRODUCTION

The Sucker Creek flora of southeastern Oregon and
southwestern Idaho is only one of a complex of floras and
florules from the Columbia Plateau and adjacent regions
in Washington, Oregon, and Idaho. An extensive record
of the Tertiary flora of the general region is preserved
in a variety of sediments derived from widespread regional
volcanism in middle and late Tertiary time. As pointed
out by Chaney (Chaney and Axelrod, 1959), the large volume
of sediments and extensive impoundment of local basins
produced ideal conditions for fossilization of plant
material at many locations in the Pacific northwest dur—
ing Miocene and Pliocene time.

The Sucker Creek flora is actually a composite
entity built up from data acquired from approximately a
dozen florules from localities in the general vicinity of
Sucker Creek in southeastern Oregon. The center of the
fossil—bearing area is located approximately 35 miles
southwest of the town of Nampa, Idaho and most of the
localities are accessible by means of Sucker Creek Road,

a graded dirt road which branches northward from U.S.

 

3v

Route 95 approximately 0.1 mile southwest of the highway

bridge across Sucker Creek and about 2.3 miles southwest

of the point where Route 95 crosses the Oregon - Idaho

state line. Figure 1 shows the general location of the

region in relation to an outline map of the states of Oregon

and Idaho and also indicates the geographic relationships of

the various localities which will be discussed in this paper.
The first known collections in the Sucker Creek

area were made by Lindgren and the material appeared in

a report by Knowlton on the Payette flora (1898). Accord-

ing to Graham (1965), Chaney and Berry both made small

collections in subsequent years. The largest of the early

collections, reportedly consisting of several hundred

specimens, was made by HinShaw in 1923. This material

was deposited in the Carnegie Museum and was studied by

Brooks in 1935. Smith collected in the area during

several field seasons in the early 1930's and reported

on the material in 1938 and 1939. About 1935 Percy Train

collected approximately 750 specimens in the area on

consignment to the University of Michigan. Some interest-

ing specimens from this suite were described by Arnold in

a series of papers (1936a, 1936b, and 1937). The flora

was briefly considered by Chaney and Axelrod (1959) in

‘their monographic treatment of the Miocene floras of the

(Ralumbia Plateau. The most definitive treatment to date

was presented by Graham (1965). Graham undertook a revi-

sitnn of all of the macrofossil material from the various

 

 

 

 

 

 

 

 

 

 

 

 

OREGON
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#
@ROCRVILLE SECTION ROAD OR TRAIL ~
@SHORTCUT SECTION PERMANENT STREAM o-"--..--"
@VALLEY SECTION INTERMITTENT STREAM

@OUARRY LOCALITY
@MAPLE RIDGE LOCALITY
@PINE LOCALITY

FIGURE 1, Outline map of the study area showing the location
Of sites discussed in the text.

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collection Sites and made numerous new collections in the
area. In addition to this conventional paleobotanical
treatment, Graham also described the pollen grains and
spores preserved in the rocks at some of the macrofossil
collecting localities. This initial study of Sucker Creek
palynomorphs added a number of new taxa to the flora in
addition to confirming the presence of taxa previously
established on the basis of fossil leaves or seeds. Graham
considered the flora to represent a warm temperate lowland
deciduous forest complex which graded into communities of
cooler aspect at higher elevations. Axelrod (1969)
includes the Sucker Creek flora in his analysis of the
topographic history of the Snake River Basin. On the
basis of the macrofossil assemblage, Axelrod classified
the flora as a mixed deciduous hardwood Slope forest.

One of the principal limitations to our present
understanding of the nature of the Sucker Creek flora is
the complete lack of any stratigraphic control between
the various collecting localities. The various florules
are assumed to represent the same floristic entity and
are considered together in any discussion of the fossil
.flora of the area. Such a practice is often resorted to
ir1 studying Tertiary floras of the Western interior where
-the isolated nature of the depositional basins makes
(norrelation between localities difficult or impossible.

In light of this problem, the present study has

tum) main objectives. The first of these is to describe

the stratigraphic interval during which most or all of the
plant fossil-bearing beds were deposited with a goal of
properly intercalating the various collecting localities
into this local sequence. Once the stratigraphic sequence
was established, the second major Objective involved samp-
ling the entire study interval and evaluating the quantita-
tive and qualitative distribution of the various palyno—
morphs. The bulk of this paper is devoted to describing
the methods, results, and conclusions arising from this

study.

ahe—

 

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.

CHAPTER II

METHODS

Field Procedures

 

The author made an initial field reconnaisance of
the Sucker Creek area in 1969 during a collection trip in
the company of Dr. Aureal T. Cross. Dr. Cross had made
additional collections in the area during the 1962 and
1965 field seasons and his familiarity with the area, both
on the basis of his own experience and various published
reports, was of great assistance.

The bulk of the field work was undertaken during
the summer of 1970. The initial stages involved a careful
reconnaisance of the area with the aid of aerial photo-
graphs, a preliminary version of the U.S. Geological
Survey 15 minute Rockville Quadrangle Sheet, and previous
reports and field notes. The purpose of this phase was
to loCate as many of the plant-bearing localities as
possible and to choose geological sections which would be
suitable for detailed study. The assistance of Dr. Cross,
who joined the author in the field for a week during this
phase of the study, was invaluable in helping to define
the stratigraphic relationships of certain of the produc-

tive megafossil localities.

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The final phase of the field study involved the
measurement and sampling of three geological sections.
The first of the measured sections is located in the
NW%NW% of T285 R46E, approximately 1.5 miles NW of the
Rockville Schoolhouse which is located at the junction
of Sucker Creek and Shortcut roads in Malheur County,
Oregon. This section will be referred to as the "Rockville
section" throughout this paper. The location of this and
the other study sections is indicated on the map in Figure
1. The second section, to be referred to as the "Short-
cut section," is located in the NW%8W% TlS R5W, approxi-
mately 1 mile north of the junction of Shortcut Road and
Route 95 in Owyhee County, Idaho. The third section,
called the "Valley section" outcrops along the course of
a small intermittent stream in the NE% T27S R46E. This
stream crosses Sucker Creek Road from the southwest
approximately 0.25 miles from that road's intersection with
Route 95 in Malheur County, Oregon.

The Rockville and Shortcut sections were measured
'with.a Brunton Pocket Transit and tape, while the Valley
exaction was measured by means of paced traverse with the
Iarunton compass. In an attempt to document most strata
vwithin the study sections, samples were collected from
eauzh lithological unit. Some particularly thick or
\nxriable units were sampled more than once. Two ten-
fobt intervals in the Valley section, each consisting

(3f 53 complex of organic siltstones, mudstones, and lignite,

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were sampled at close stratigraphic intervals in order to
document any changes in the pollen flora within that par-
ticular facies. Samples for maceration were also collected
at several of the macrofossil localities.

Fossil plants, petrified wood, and fossil animals
of interest were assigned field collection numbers and

returned to the laboratory for detailed study.

Laboratory Procedures

 

The field descriptions of rock units were recorded
in the laboratory and the field measurements reduced to
absolute stratigraphic thickness. The composite strati-
graphic sections were plotted and the location of each
field sample was intercalated into its proper section.

All samples for maceration were assigned to Michigan State
University Palynology Laboratory maceration number con-
sisting of the prefix Pb, (paleobotanical), followed by

a four digit number. These maceration numbers were cross-
indexed to the original field collection numbers in the
master maceration index on file in the Palynology Labora-

tory at Michigan State University.

Sample Processing.--The prime objective of pro-

 

cessing the rock samples from the field is to free the
eenclosed palynomorphs in such a form that they are
amenable to qualitative and quantitative study. An ideal
Iorocessing regime would not only free all types of pollen

Land spores, regardless of their relative degree of

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preservation, but would also introduce no bias in the
quantitative representation of each of the entities as
originally contained in the parent rock matrix. There are
no techniques which will completely satisfy these rigid
requirements and those which come closest are not appli-
cable to a wide variety of sediments. Thin—sectioning
where the palynomorphs are observed in EEEE within the
parent matrix probably introduces a minimal bias and such
techniques were used by Wodehouse (1933) in his study of
the Eocene pollen of the Green River oil shales. Unfor-
tunately, the limited occurrence of rocks with the
requisite high pollen concentrations and suitable optical
qualities in thin section greatly limits the scope of such
techniques.

A more commonly used approach involves the chemi-
cal or physical disaggregation of the rock matrix to free
the enclosed material for study. Brown (1960) and Gray
(in Kummel and Raup, 1965) present useful summaries of the
techniques now in use. Most laboratories employ relatively
standardized techniques for treatment of various types of
samples, but such procedures are, at best, guidelines from
which optimized techniques for specific samples must be
developed as the need arises. Samples from the Sucker
Creek area vary considerably in their lithology and pollen
and spore content and considerable time was devoted to the
{problem of developing a processing regime which would be

Isatisfactory for a majority of the samples. Lignites,

10

lignitic shales, and highly organic Silt and mudstones
were usually characterized by high concentrations of well
preserved palynomorphs and presented no particular sensi-
tivity to details of the extraction procedure. The various
volcanic shales, bentonites, and sands, which comprised
the bulk of the measured sections, usually had low pollen
and spore concentrations coupled with marginal preserva—
tion. Any procedure involving treatment with strong
bases, boiling in acid with subsequent oxidation at the
air-liquid interface, or attempts to refine the organic
fraction by treatment with oxidants such as nitric acid
(HNO3) or Schultze's reagent, a mixture of nitric acid
and saturated potassium chlorate (KC103), tended to result
in either barren preparations or slides of poor quality
with skewed palynomorph distributions. Although there is
no empirical way to judge the effectiveness of any pro-
cessing schedule, other than by comparison with the
results of other techniques, the procedure to be described
was successful in producing useful pollen and spore pre-
parations from the greatest number of samples.

A typical sample consisted of either 10 or 20 grams
of sediment. The decision as to the weight of samples
to be processed was based on an intuitive evaluation of
the probable productivity. The sample was crushed in a mor-
tar vdth a pestle until the largest fragments were approxi-
xmately pea-sized. A sample of the parent rock was tested

witji a 10 percent solution of hydrochloric acid (HCl) and

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11

if any effervescence was observed, the sample was soaked
in 5 percent HCl for 12 hours and then washed with water
several times to remove any trace of acid. Samples which
were not reactive to HCl were immediately introduced into
the next stage in processing.

A 200 ml polyethylene beaker was filled to 1/3
capacity with crushed ice and 70 percent reagent grade
hydrofluoric acid (HF) was added until the beaker was
filled to the 100 ml mark. The beaker was placed under
a fume hood and the entire sample was immediately poured
into the acid-ice Slurry and stirred with a plastic stir-
ring rod. The purpose of this procedures was to completely
eliminate the possibility of the solution boiling when the
sample was added. Most of the Sucker Creek samples were
highly reactive when placed in HF and the elimination of
boiling appeared to significantly increase the yield of
pollen and spores in marginal samples. The samples were
allowed to stand in HF overnight under the fume hood.

The next morning the excess acid was decanted and the
samples were washed several times in water to remove all
traces of the acid. Polyethylene beakers and centrifuge
'tubes were used until the final water wash, after which
tflne samples could be transferred to glassware.

The samples were washed once in 5 per cent HCl and
'the excess acid was decanted off. Approximately 25 m1 of
sen:urated zinc chloride (ZnClZ) solution (Specific gravity

J“.95) was added to the centrifuge tube. The sample was

12

suspended in the heavy-liquid and given several seconds
treatment in a Branson Instruments model PZ—150 "Sonogen"
ultrasonic generator to homogenize the suspension. Treat-
ment in excess of 30 seconds was avoided as more lengthy
treatment tended to fragment vesiculate pollen types.
The sample was then centrifuged for 15 minutes at 1550
r.p.m. and the floating and suspended organic fraction was
decanted into a clean centrifuge tube. The tube was
filled with water and the contents were carefully mixed
so that the organic material could be spun down on a sub-
sequent run on the centrifuge. The organic fraction was
washed several times in water to remove all traces of
zinc chloride. The zinc chloride solution is corrosive
to pollen grains and spores and care was taken to limit
the time during which the samples were exposed to this
reagent.

Samples of sufficiently high quality at this
stage in the processing were stained and stored in vials
of glycerin jelly for later mounting. Most samples how—
ever had sufficiently high concentrations of clay particles
ennd fine organic detritus to justify further processing.
(Phese samples were sieved through a Buckbee Mears Company
IflHC Micro Mesh screen with a nominal mesh size of 20
nd13rometers. Any material remaining on the surface of the
scnneen was transferred to small glass sample vials. A
ndxzroscopic examination of the <20pm fraction was made and

if'eany pollen grains were noted, the fraction was re-sieved

 

13

with a BMC 10 micrometer sieve and the >10 fraction was
added to the >20 material in the sample vials. The use
of the micro-sieves was resorted to only when debris

made observation of the palynomorphs difficult due to
mechanical interference or dilution effects. The residue
was stained and stored in glycerin jelly for later
mounting.

A drop of the glycerin jelly residue was mounted
on a standard microscope Slide and cover slip. The cover
glass was ringed with clear nail enamel to prevent drying.
Four slides were prepared from each vial of residue where
volume permitted. Excess residue from each sample was
stored in tightly capped glass vials. All slides used
in this study are on file in the Palynology Laboratory at

Michigan State University.

Analytical TechniqueS.-—A Leitz Ortholux micro-

 

scope (serial number 599742) was used for all observation
and photography during the study. All of the Slides
available were examined for the occurrence of new palyno—
morphs or specimens of particular interest. The location
of such specimens was recorded using the coordinates on the
calitmated mechanical stage. In addition, each slide was
given a small cross to the right of the cover slip using

a dianwnd marking stylus. At the conclusion of the study,
tine location of all described specimens was computed on

time basis of the distance above or below and to the left

14

of the reference mark. A given taxonomic description

might include the following information under the loca-

tion heading:

Pb-930l-3 +5.6X9.1

The specimen in question would be found on the third slide
prepared from residue PB-9301. The specimen could be
located on this slide by centering the reference mark in
the low powered field and moving the stage 5.6 mm above
the reference mark and 9.1 mm to the left. The horizontal
coordinate always represents the distance to the left of
the reference mark, while a + or - Sign next to the verti-
cal coordinate indicates a distance above or below the
reference mark. In all cases, the slide is placed in
the stage holder with the label to the left of the observer.
Specimens were photographed using a Leitz Orthomat
microscope camera system. Both Kodak Plus-X and Panatomic
X films were used. Processing and printing followed
standard techniques. Enlargements were adjusted so that
the effective magnification on the final plates was 1000X.
Identification of the various palynomorphs was
enscomplished by comparison of the unknown Specimen with
iJIformation from three sources; standard reference texts
SLuzh as Wodehouse (1935) and Erdtman (1943, 1966, 1969);
ptflolished papers; and modern pollen reference slides.
Tfiue latter source is the most definitive and was used pref-

(arenntially whenever adequate material was available.

15

A quantitative evaluation of the palynomorph
assemblage of each productive sample was made by making
systematic traverses of the slides, tallying the pollen
grains and spores encountered until a total of 200
palynomorphs had been counted from each sample. Occa-
sionally a smaller sum had to be used due to low pollen
and spore concentration, but every attempt was made to
tally 200 grains if adequate material was available. In
order to eliminate size bias from the counts, only those
grains whose geometric centers were included in the field
of view were counted. Detached bladders of vesiculate
grains were not tallied, while the bodies of such grains
were counted as a Single grain, regardless of the number
of attached bladders. Algae, fungal entities and bryo-
phyte spores, while included in the qualitative evaluation
of the samples, were not included in the sample counts,
which included only those forms which could safely be
considered either pteridophyte spores or gymnosperm or
angiosperm pollen grains. Those palynomorphs of vascular
origin which were poorly displayed or too poorly preserved
to permit either identification or consistent recognition
‘were tallied as "Undifferentiated Unknowns." Entities
vfliich could not immediately be identified but which were
sufficiently distinct to allow consistent recognition were
(given numerical designations and tallied separately. In
tjqis manner, data were not lost in the event the entity

ccnild ultimately be identified. The relative percentage

16

for each entity in any given sample was calculated from

the following formula:

% = EBx 100

where Np is the number of grains of the type in question
and FS is the fixed sum or total number of entities counted
for the sample in question. The total array of all rela—
tive percentages for any given sample constitutes the

pgllen spectrum of the sample. For an entire section,

 

the data from the various pollen Spectra are arrayed ver-
tically in the form of a saw-tooth graph to Show the

Shifts in relative per cent contribution of each entity
throughout the entire section. Pollen profiles constructed
from the study data appear in Figures 5 through 8 and are

discussed in the chapter on stratigraphic palynology.

CHAPTER III

GEOLOGY

Physiography

 

The Sucker Creek area is considered part of the
Owyhee Upland region of the Columbia Plateau physiographic
province and is located just north of the Great Basin
province (Dicken, 1955). The region's complex surface
features are developed on basaltic and rhyolitic Sheets
which range from Miocene to Recent in age. Permanent and
ephemeral streams have formed numerous gorges in the
region with a variety of land forms produced as a result
of the differential rates of erosion of intrusive, extru-
sive, and sedimentary rocks. Virtually all of the
sedimentary rocks in the area consist of reworked clastic
material of volcanic origin. Relief varies from 2,230
feet at the level of the Snake River (Kittleman, 1962) to
8,065 feet in the Owyhee ranges near Silver City, Idaho.
Elevation in the fossil leaf area is in the order of
3,500 feet with the adjacent Mahogany Mountains reaching
(5,500 feet. The Owyhee Upland is drained by the Snake

Ikiver which has two main tributaries in the study area,

17

 

18

the Owyhee River, now dammed as an irrigation reservoir,
and Sucker Creek. Sucker Creek drains the east slope of
the Mahogeny Mountains and carries water throughout the
year. McBride Creek and Carter Creek are the two main
tributaries of Sucker Creek in the study area. In both

of these there is very little water flow during the
warmest months. According to Kittleman (1962), the pro-
file of the valley of Sucker Creek suggests at least one
cycle of erosion Since the inception of the present drain-

age system.

Structure

 

Folding in the area is comparatively gentle. The
only feature of any note in the study area is a small
anticlinal ridge near the point where Sucker Creek crosses
Route 95 (Kittleman, 1962). Assessment of regional dip is
difficult due to the lenticular nature of most strata, but
appears to average 1—3 degrees westward. Locally dips may
be as great as 500 when beds are disturbed by tilting of
fault blocks or localized warping. No dips in excess of
100 were noted in measuring any of the study sections and
.in almost all cases these dips tended west. The numerous
faults in the area tend north—south and are, according to
Icittleman (1962), indicative of at least four periods of

(Leformation.

19

Stratigraphy

The stratigraphic relationships of the rocks of the
Owyhee Upland area in general and the Sucker Creek area in
particular have undergone varying degrees of study through-
out the years, but even the most recent work in the area
has failed to completely unravel the complex relationships
of the many isolated basins in which sediments were accumu—
lating during late Tertiary time. Cope defined the Pliocene
Idaho Formation in the area on the basis of fossil fish in
1883. Lindgren defined the Payette Formation in 1898 and
considered it to be Upper Miocene in age on the basis of
the fossil plants studied by Knowlton (1898). Both the
Payette and Idaho Formations were recognized in the map-
ping of the Nampa and Silver City areas by Lindgren and
Drake (1904, 1904a), but no clear distinction between them
was made at that time. Both formational names were used
by Kirkham (1931) working in the western part of the Snake
River Plain east of the Owyhee Upland, but again, the
formations were poorly defined. Kirkham did note that
the Miocene Payette is often separated from the Pliocene
Idaho by a rhyolite which he called the Owyhee Rhyolite.
Locally, a basalt, which he called the Owyhee Basalt, is
(Often present above the Owyhee Rhyolite. Additional map-
15ing and work in the area by Bryan (1929), Renick (1930),
(Borcoran (1953), and Doak (1953) clarified the relation-
:Ships of some of the interbedded rhyolites and basalts

kNit retained the Payette - Idaho nomenclature for the major

20

sedimentary units. Chaney (Chaney and Axelrod, 1959)
considered the plant-bearing beds of the Sucker Creek
area to be of essentially the same age as the Payette of
Kirkham (1931) but felt that they represented a distinct
facies which, when more fully understood, might justify
the application of a new formational name. Kittleman's
thesis (1962) on the geology of the Owyhee Reservoir area
redefined the nomenclature of many of the units in the
area. Kittleman felt that, Since it was not possible to
directly correlate the rocks in the Owyhee Reservoir area
with those definitely known to belong to the Payette and
Idaho sequence, the use of new names for these units was
justified. The history of the stratigraphic terminology
for the rock units in the area is summarized in Figure 3,
while Figure 2 summarizes the regional correlations of
these units with sections in other parts of Oregon.
Kittleman proposed the name Sucker Creek Formation for
beds presumably equivalent to the Payette and renamed the
overlying rhyolite the Jump Creek Rhyolite since the name
Owyhee had already been preempted for the basalt. The
old.Idaho equivalents were elevated to group status and
rue proposed the names Deer Butte and Grassy Mountain
Ekarmations for the two component units of the new group.
All of the fossil plant localities occur in the
aixaa which Kittleman maps as the Sucker Creek Formation
(1962). Kittleman defines the formation as consisting of

aguoroximately 1,600 feet of interbedded volcanic and

21

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arkosic sandstones, arkosic conglomerates, and carbona-
ceous volcanic shales. There is a tuff member, the Leslie
Gulch tuff member, to the east and a poorly known basalt
near the base of the formation. The base of the formation
is not exposed in the area. Unfortunately, the type
section consists of approximately 400 feet of sediment

at the top of the sequence. The type section is located
considerably to the north of the plant fossil area in

8% SW% Sec. 28, T.24S., R.46E. in Malheur County, Oregon.
The relationship of the study sequence to the Sucker Creek

formation (sensu latu) of Kittleman will be discussed

 

later in this chapter.

Graham (1965) does not discuss the stratigraphic
relationship of any of the plant localities in his treat-
ment of the flora.

Detailed data on each of the measured sections is
contained in Appendix A. The following discussion will
involve somewhat more generalized comments on the nature
of the section at each locality with reference to the

generalized correlation diagram in Figure 4.

Rockville Section.~-The Rockville exposure is

 

easily accessible from Sucker Creek Road just north of its
Junction with Carter Creek Road (Figure l). The upper
part of the sequence is exposed along the east flank of

a ridge directly west of Sucker Creek road at this point

and the entire section is exposed in the valley system

IN FORMAL

LGray sha
2.0ranic
3.50nd

4.White as
5.Green
6. Insect be

ROCKVILLE

l

 

 

 

U

 

 

 

24

 

 

 

h

d

 

 

 

interval

shale

7.0rgonrc interval

8.Valley plant beds

9. Upper swamp series

 

 

 

 

 

 

 

 

 

 

SHALE

SAN DSTONE

[IGNIYE OR
ORGANIC
SEDIMENT

50 FEET

 

 

FIGURE 4.

Generalized diagram at the rock units
correlations. line A—A' marks

present

at

each

section.

 

 

of each of the
the base of

the prominont

study sections and
white ash bed

 

 

 

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the

proposed
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In

'TS

25

behind this ridge. A photograph of this latter exposure
appears in Plate 1 and was taken facing northwest from the
top of the ridge paralleling Sucker Creek Road. A small
dirt road branching off of Sucker Creek Road just beyond
the ridge offers convenient access to the entire valley
system. The oldest sediments in the section outcrop at
the base of the knoll to the far right in Plate 1 and
consist of approximately 5 feet of greenish bentonitic
shale overlain by approximately 1 foot of sandy shale,
also somewhat green in color. Several feet of organic
shale overlie the sandy shale. The lower part of the
sequence is highly fossiliferous and numerous very fine
fossil leaves have been collected. The matrix is a fine
shale with a very light maroon color. The leaves are
predominantly of the Quercus consimilis type and the stem

tips of Equisetum octangulatum. The top of the unit con-

 

sists of a light brown highly fissile shale containing
numerous plant fragments and insect parts. This very
characteristic bed will be referred to as the "Insect

Bed." The Insect Bed is overlain by a thin green bentonitic
shale which in turn is overlain by a prominent white ash
bed approximately 22 feet in thickness. This ash weathers
to a pure white color but on close examination can be seen
to contain tiny black mineral inclusions and carbonized
plant fragments. This bed is a very prominent.marker in
the section and is easily visible in Plate 1 wherever it

(Jutcrops. The white ash is overlain by approximately 35

..
4". - f?
t
,I

 

 

 

26

feet of cross bedded, poorly consolidated sand. The sand
is overlain by another sequence of organic shales. This
shale sequence contains entire petrified tree stumps
rooted in place. Numerous pockets of fossil wood, repre-
senting weathered tree stumps can be seen along the top
of the ridge paralleling Sucker Creek Road and a number of
intact stumps may be seen in £352 on the northwest slope
of the hill located behind the prominent ridge in the
center of Plate 1. There are several feet of sand
overlying the shale sequence followed by a thick shale
with little organic material. This shale grades from
gray or brown at its contact with the sand to a

highly indurated form at the top of the section which
weathers to tan or rust brown along exposed edges and
contains seeds of Cedrela trainii. These beds may be
traced laterally to several outcrops along the upper part
of the cut-off trail from Sucker Creek Road. The lithology
and fossil content of these beds is identical to that of
the Specimen Ridge (Quarry), and Pine localities while
the Maple Ridge beds (Figure 1) would appear to represent
an even more indurated form of the same shale sequence.
'The uppermost Rockville shale bed would appear to be the
stratigraphic equivalent of all three macrofossil locali—
‘ties. The Rockville section consists of approximately 95
fee¢.of sediments which were deposited under conditions
:ranging from stagnant swamps through quiet water and main

rdnver channel environments.

 

(in

27

Shortcut Section.--The Shortcut section is clearly

 

exposed and easily accessible from Shortcut Road across
McBride Creek approximately 0.5 miles from the junction

of Shortcut Road and Route 95. The section consists of
approximately 115 feet of sediment and is illustrated in
Plate 2. The base of the section consists of approximately
20 feet of poorly consolidated green sand with thin bands
of organic material toward the top of the unit. Overlying
the sand is a series of organic shales, mud and siltstones,
and lignite. Fossil wood fragments are found weathering
out of this zone. At the top of this unit is a bed of

thin fissile brown shale with insect parts. This bed is
identical in all respects to the insect Bed of the Rock~
ville section. Immediately above the insect layer is a
thin green bentonitic shale overlain by a prominent white
ash bed, apparently identical to that of the Rockville
sequence. A poorly cemented cross-bedded sand overlies

the white ash. This sand has water~worn pebbles up to 3
inches in diameter in the upper two feet. The sand is
overlain by a thin shale and approximately 2 feet of addi-
tional sand. An organic shale layer overlies this sand and
Contains pockets of fossil wood which are apparently derived
fronlthe weathering of logs or stumps. Depositional environ-
Hmnnts represented in the section appear to include stagnant
VWiter, relatively quiet water, and major distributary

Cheuinels. The presence of the larger pebbles at the top of

 

.Ilkll'fi...

 

 

28

the sand unit would appear to indicate an environment of

fairly high energy.

Correlation of the Rockville and Shortcut Sec-
tions.--The Rockville and Shortcut sections correlate quite
closely on both lithological and fossil criteria. The
vertical sequence indicated below is common to both sec-
tions. The numbers assigned to these units correSpond

to those of Figure 4.
l. gray shale

2. organic interval
(wood)

3. sand

4. white ash
5. green shale
6. insect bed

7. organic interval

TTKB lithological character of each unit as well as their
:relxative positions match perfectly between the two sec-
ticnis. The general patterns of the correlations are indi—
catxai in Figure 4. The only uncertainty regards the

perZiSe point where the oldest sediments at Rockville fit

 

3.. .0

&L

29

into the Shortcut complex and where the youngest Shortcut
beds fit into the upper Rockville sequence. There is
little doubt that the two sections represent virtually
the same sedimentary interval, overlapping in such a way
that the very oldest sediments are found at the base of
the Shortcut section and the very youngest rocks are

found at the top of the Rockville section.

Valley Section.--The Valley section is exposed

 

along the course of a small intermittent stream near the
junction of Sucker Creek Road and Route 95. The base of
the sequence consists of approximately 5 feet of gray
clay-shale which is overlain by a thick sand varying in
color from rust-brown to olive green, depending on the
degree of weathering. The cement exhibits weak efferve-
scence with HCl. Approximately a third of the way up
this unit there is a thin limey layer of very hard rock.
This layer is gray in color and is rich in organic
material. The sand continues up to the 165 foot layer
where it is overlain by a brown shale containing numerous
plant fragments and a few fossil leaves. This shale is
overlain by a 10 foot sequence of lignite and organic
Inudstone and siltstone. Small varves of sand and mica
flakes are common in this unit. Above this unit is a
sandy brown shale which is overlain in turn by another
(organic unit much like the first. Above this unit is a

'thick series of fine-grained shales of a very light maroon

all!“

02:

 

30

color. Fossil leaves of extremely high quality are very
abundant in the lower part of the shale sequence. Of all
of the leaf-bearing beds in the Sucker Creek area, these
beds are unsurpassed in the number and quality of the
leaves, fruits, and seeds which can be collected here.
Particularly fine specimens of Glyptostrobus, including
branches with attached male and female strobili, Quercus,
Aggr, Salix, and a variety of other deciduous leaves have
been collected. Another organic series overlies the
shale sequence. A thin green bentonitic ash overlies the
organic sequence and is overlain in turn by a white ash
typical of the Rockville-Shortcut complex. Above the
white ash there appears to be an unconformity which may
represent the contact between the Sucker Creek formation
and later Miocene sedimentary rocks and flows as mapped
by Kittleman (1962). The correlation between the Rock-
ville and Shortcut sections and the Valley section is
difficult on lithological grounds alone. The white ash
and underlying green shale appear identical to similar
'units in the other study sections and the correlation of
'those beds is indicated in Figure 4. The top of the white
gash at the Valley section is probably truncated by ero—
ssion and may not represent the total thickness originally
«deposited. The complex organic beds characteristic of
kxath Rockville and Shortcut are difficult to relate to
tflue Valley sequence and the correlation indicated in

Ftigure 4 is largely based on palynological data and is

 

Vb

is

31

fully discussed in the following chapter on stratigraphic

palynology.

Relationship of the Study Sections to the Sucker

 

Creek Formation.--There is little doubt that the composite

 

stratigraphic sequence described in the present study
represents a well defined and mappable unit. The diffi-
culty is in relating this unit to the Sucker Creek Forma-
tion as defined by Kittleman (1962). As stated previously,
only approximately 400 feet of section are expressly
defined in the type section, with the majority of the
mapping of the full extent of the formation carried out
using topographic criteria. The sediments of the study
sections appear to contain most or all of the fossil plant
beds but do not have any lithological similarity to the
type section to the north. The fact that all of the

study sections are truncated and overlain by flows younger
than the Jump Creek Rhyolite might tend to indicate that
the study sequence represents an older unit than the type
section. Within the study sections, progressively

younger sediments are exposed when traced northward, a trend
which, if continued, would also indicate a younger age

for the sequence to the north at the type locality. The
presence of a tilted fault block in which progressively older
sediments are exposed southward is a distinct possibility.
Kittleman (personal written communication) feels that this

is a viable hypothesis. Hills to the ESE of the junction

32

of Route 95 and Sucker Creek Road have exposed sediments
which seem to be similar to the beds of the type section,
even to the presence of well-defined opaline layers, which
are lacking in any of the study sections. If the study
sections are part of a fault block, a fault associated
with the anticlinal ridge near the junction of the two
roads is required to explain the close juxtaposition of
otherwise unrelated sediments. A provisional assessment,
in the absence of further work in the area, would at least
tend to indicate that the sedimentary interval represented
by the study sections is older than that of the type
section.

The problem of the proper nomenclature of this
and other units in the area is not as easily solved.
Repeated traverses from the plant-bearing beds to the
south and the type section to the north failed to indi-
cate any lithological connection between these important
units. On the basis of such a lack of direct correlation,
there appears to be no valid reason for including the
plant-bearing units to the south within the Sucker Creek
Formation. There is little doubt that the complex of
sediments mapped by Kittleman as the Sucker Creek Forma-
tion is in need of redefinition and possible modification
of nomenclature. The type beds to the north contain a
fauna which has been referred to in the literature as the
£3ucker Creek fauna and any nomenclatural change should,

.if possible, retain some reference to the term Sucker

33

Creek for both the flora and fauna. One alternative might

be to raise the present Sucker Creek Formation (sensu latu)

 

to group status and redefine the type section and the sedi-
mentary interval of the present study as separate formations,
provided the relative stratigraphic relationships could be
determined with somewhat more certainty than they are known
at present.

Giving both units member status within the Sucker
Creek Formation as presently mapped is untenable for two
reasons. First, as discussed previously, there are at pre-
sent no grounds to consider the present formation, as mapped,
to have any stratigraphic continuity, and secondly, both of
the units to be included are composed of diverse lithologi-
cal constituents while members, in the commonly used sense,
are usually of relatively homogeneous composition.

In any case, the plant-bearing beds in the Sucker
Creek area would appear to belong to a definable strati—
graphic interval. A task remaining for future investiga—
tion is the relationship of this unit with other sedimen-
tary intervals on a broader scale to more clearly define

the late Miocene sequence in the area.

Age of the Flora.--Based on the evidence of the

 

fossil plants of the macroflora, Chaney and Axelrod (1959)
considered the flora to be late Miocene in age. Graham
(1965) concurred in this view. According to Kittleman

(1962) the sediments in the type section are late Barstovian

34

in age based on the fossil mammals recovered from those
rocks. Evernden et_al. (1964) gives a date of 16.7

million years for a plagioclase sample from the Sucker

Creek region. Although precise collection data was not
available, James, one of the authors of the dating paper,
recalls that the sample was collected approximately 9

miles north of Sheaville along U.S. Route 95 just east of
the point where the road curves sharply to the northeast
(personal written communication to Dr. A. T. Cross). This
sample was interbedded with ash beds and evidently represents
an isolated flow structure too small to be marked on Kittle-
man's map (1962). Although the collection site is located
not far from the Valley section (Figure 1) it is in an

area where fault activity is suspected and its relation-
ship to the study sections is not clear. Barring a

closer correlation of dated material with the composite
study sequence, a late Barstovian age for the leaf—bearing
sediments is the best approximation that can be made at

present.

,_,
.mv
‘.\

CL

f'fi

in

CHAPTER IV

STRATIGRAPHIC PALYNOLOGY

The material in this chapter will consist of a
description of the patterns exhibited by the relative
frequency pollen profiles from the study sections. The
ecological implications of the profiles will be discussed

in the following chapter.

Valley Section

 

The sediments of the Valley section are character-
ized by relatively productive samples with the general
exception of the poorly cemented sand which comprises the
lower 180 feet of section. The only productive samples
in this interval were derived from a clay-shale at the
base of the section and a thin limey layer at the 275
foot layer. The quantitative data for the entire section
are summarized in Figure 5. The pattern on palynomorph
distribution appears to be relatively consistent from the
base of the section up to the 150 foot level where the
first of the extensive swamp deposits appear. The most
jprondnent component of the microflora throughout this

interval is the pollen of the genus Picea, which varies in

35

‘m- «- '

-_.
e.

36

 

 

 

Figure 5.--Re1ative frequency pollen and spore profiles from
the Valley section. Relative frequency, in per
cent, is indicated in a horizontal direction while
the level within the section is indicated on the
vertical axis.

VALLEY SECTION

NMONINfl
{NMONlnn
um ‘ DSIVI
(On

IVINIWVIO

3 vstSOawO)
Iv 'ONIHD
3'33"”va
vuul

N01 JDOWVIOJ
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IVJ)VNOVIVH
IVIJVIOVNO
luvs

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SON!"
Vl‘ll

$030300
VAIVDOIIIJ
snvtonr
IVIVOInOtI
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V101 !.

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IIDV

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not: 333
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37

IIlAYIVE FIIOUENCY

NONI?! OI
OIOANUC

SIDIIENI

In
III-l
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38

relative percentage from 25 to 35 per cent. Pings pollen,
ranging from approximately 30 percent at the base of the
section and maintaining a level of approximately 10 per-
cent throughout most of the interval, is second in

importance closely followed by Alnus, Abies, and Ulmus.

 

Pollen of Tsuga, the Taxodiaceae (TCT), Quercus, Fagus,

Pterocarya, and the Gramineae are consistantly present in

 

the range of 1-2 per cent, while monolete and trilete

spores, and pollen of Carya, Juglans, Tilia, and Acer are

 

consistantly present, but never exceeding approximately
1 per cent. Other taxa are sporadic in distribution and
of little quantitative importance.

A major feature of the profile at the 150 to 145
foot level is a pronounced peak in Alnug pollen in excess
of 40 per cent. This peak is roughly coincident with a
drop in Pigga to somewhat less than 10 per cent. ééifié
and Tsuga also exhibit decreases at this point, but the
other components of the profile are comparatively unaffected.
Above this point in the section additional taxa appear,
but do not attain any great quantitative importance. These
include Betula, Carpinus, Castanea, Liquidambar, Populus,
Salix, and a number of irregularly distributed forms. In
addition to the appearance of these new taxa, the upper half
of the section is also characterized by an overall increase
in the relative importance of glmus and Quercus pollen
grains. A small peak in Abies preceeds a pronounced £3333

peak of approximately 50 percent at the 125 foot level.

39

A very pronounced peak in taxodiaceous pollen (TCT) cul-
minates at the 70 foot level and is accompanied by a
decrease in Pigea and Abies and the disappearance of
Tsuga. The TCT peak appears to coincide with a slight
drop in the relative importance of Quercus and glans
pollen. From the 70 foot level to the top of the section
there are two small TCT peaks and two peaks in Pigea and
Abies, with a similar pair of peaks in the glmus curve.
The uppermost productive sample in the section is charac—
terized by slight declines in the importance of Pigga,

Abies, Pinus, and Ulmus. and a slight increase in Alnus,

 

the Compositae, and the Gramineae.

In addition to examining the profile for the
entire Valley section, it was decided to study a single
facies in some detail to determine if small-scale suc—
cessional events were resolvable and to see to what
extent the patterns revealed by detailed sampling were
discernable in the large—scale profile. In order to
gather data on this point, a 10 foot sequence of lignites
and organic silt and mudstones was sampled in detail and
a pollen profile prepared. The sequence is located in
the 142 to 132 foot interval and the profile appears in
Figure 6. In spite of the slightly jagged profile, the
overall impression is one of uniformity in the representa-
tion of the various pollen types throughout the interval.
There are only three points in the curves which depart

fronlthis overall uniform aspect. The first of these is

40

Figure 6.—-Re1ative frequency pollen and spore profiles from
the Upper Swamp Series in the Valley section.
Relative frequency, in per cent, is indicated on
the horizontal axis while position in the section

is indicated on the vertical axis.

Qfiblcc

SECTION — UPPER SWAMp

VALLEY

VALLEY SECTION 'UPPER SWAMP SERIES

41

  
 
 
 
   
  
 
 
   
    
 
 
  
 
 
 
 
 
  
   
 
   
   
  
 

SNMUNINII
VSSAN
av;)v)laa
xin

JVJNIWVUO
JVLISOGWO)
WV ONJHD
JVJDVAIVW
VN‘AA
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AN
JVJVNOVQVla
3V

RELATIVE FUEOUENCV

XI
SI’HHJOd

llGNITE 0R
SEDIMENI

VAIVDOI 31d
IVIWVOIHOI‘I
SNVIOOI
SnDVi
VJNVLSV)
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SJIIV
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FIGURE 6.

I
W0!!! 1]]!

42

a pronounced glmus peak at 3.5 feet and the second is a
smaller peak in Quercus at 0.5 feet. The third point

is a rather pronounced and uniform increase in the rela-
tive percentage of taxodiaceous pollen (TCT) toward the
top of the sequence. This increase corresponds to the
beginning of the major TCT peak in the curve for the
entire section and it would appear that the trends within
this small lithological unit are in accord with the large-

scale but more poorly defined patterns throughout the

entire section.

Shortcut Section

The pollen profile for the Shortcut section is
diagrammed in Figure 7. The profile is characterized in
its lowest levels by a high percentage of Pigea pollen,
ranging from slightly more than 50 per cent at the 108
foot level to about 1 per cent at 75 feet. There is a
secondary peak at 72 feet and the pollen disappears from
'the record by the 62 foot level. Abies and Tsuga occur
in moderate numbers in the lower portion of the section
but disappear by the 72 foot level. Alnu§_pollen occurs

at.levels of 1-5 per cent in the lower part of the section
‘with a peak of 59 per cent at the 75 foot level. There is

a rapid reduction to approximately 2 per cent at the 72 foot
level, with this low percentage being maintained through-
(Jut the remainder of the section. Of the remaining angio-
sfipermous pollen types, glmus is probably the most impor-

tarfly ranging from 2 to 12 per cent in the lower portion

43

Figure 7.--Relative frequency pollen and spore profiles from
the Shortcut section. Relative frequency, in per-
cent, is indicated on the horizontal axis while
position in the section is indicated on the
vertical axis.

44

SNMONan
”not

 

area

a

>U2w30wxm w)...(.u-

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priawm
U_2<U-O
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WV *ONSND

JVIISOGWOD
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SNVIDOI

ZO_.—Umm PDUP¢OIm

45

of the sequence, becoming reduced to l per cent at the 72
foot level and disappearing from the record by 62 feet.

A number of other pollen types, including Betula, Eggxgy
Castanea, Fagus, and Juglans exhibit similar patterns in
that they commonly occur in the lower part of the sequence
but disappear from the record by the 72 foot level. The
A225 curve is quite similar except for a limited occur-
rence at the 8-9 foot level. Quercus and Pterocarya are
well represented in the lower third of the section and
persist at reduced numbers above 72 feet. Pollen assigned
to the Gramineae shows a similar pattern except for a
secondary peak near the top of the measured section. The
pollen of §Eli§ and the Taxodiaceae (TCT) is found with
little change throughout the section. The pollen of Pinus,
despite a reduction at the 75 and 72 foot levels shows a
general increase in relative importance from the base to
the top of the sedimentary interval. Pollen of the Com-
positae is the most significant group in the upper part

of the section. The grains are virtually absent from the
Lhawer section, gradually rising to a value of 5 per cent
art the 75 foot level. At this point the curve begins a
.rapiclincrease reaching approximately 30 percent at 62
feet and generally this percentage is maintained to the top
(If the section. A number of differentiated unknown pollen
types exhibit a similar pattern. Other, less numerous

pollen, taxa whose distribution is wholly or partially

 

46

confined to the levels above 72 feet inclue Populus,
Malvaceae, Cheno-Am, Unknown 63 and Unknown 72.

The general pattern of distribution of the various
palynomorphs throughout the section is characterized by
a significant shift in dominance of the various pollen
types. This shift occurs at approximately the 72 foot
level near the top of a series of highly organic sedi—

ments.

Rockville Section

 

The pollen profile for the Rockville section is
illustrated in Figure 8. In the lowermost part of the
section the pollen dominant is Pigea, approaching 40 per
cent in two peaks near the base of the section and drop-
ping to a very low value by 82 feet. Pigga pollen per-
sists at this relatively low percentage throughout the
remainder of the section. Abigs and ngga generally show
a similar pattern but with peaks in the order of 5-6 per
cent. Both types disappear from the record by the 82 foot
level. Pings pollen is well represented although some-
what variable in the lower part of the section and gradu-
ally increases in importance upward, reaching a peak of
almost 70 per cent at a level 2-3 feet above the top of
the measured section. HlEEE pollen is quite important in
the lower section but disappears from the record at the

82 foot level. Betula, Carpinus, Carya, Fagus, Liquid-

 

 

ambar, Juglans, and Pterocarya show similar distribution

 

47

Figure 8.--Re1ative frequency pollen and spore profiles from
the Rockville section. Relative frequency, in
per cent, is indicated on the horizontal axis while
position in the section is indicated on the verti-

cal axis.

 

 

ROCKVILLE SECTION

48

  
    
   

III-Ionian

SNAOV‘INA
“Ia I )slu

cur

 

)Vll‘Ol-OJ

llAAlIVE IIIOUINCV

WV 0ND!)

lvlnvnvw
nun
MolloOivso‘

cnmdoa

“turn
“I”

Wanna

VAIVDOI I H
SKVIOIH
uvswvaunan
Sflov‘
VDNVISVJ
VAIVJ
snmelv)
vmne

noun! on
SIDIHINI

lflflIV
II)V

quIOIIun
ll'IHDIEIA

SnNII

tons:

VIDI‘

Sill!
Inn“
ill‘ONOI

Aoormun
flill‘lVlIMl'J
NOIIDIS

Ian III!

00'
“J
c:
=
(.0
Id-

49

patterns. Acer, Alnus, Castanea, and Tilia are best

 

 

represented in the lower part of the section and are
sporadic in occurrence above 82 feet. Taxodiaceous pollen
(TCT) is variable in the lowermost part of the section
and persists at somewhat reduced numbers from 82 feet
through to the top of the section. Quercus pollen occurs
throughout the entire section but reaches its greatest
relative importance above 82 feet. Populus and Sglix are
both irregularly distributed throughout the interval.
Poorly represented in the lower part of the section, but
dominant above the 82 foot level are pollen types such

as the Compositae, Cheno-Am, Malvaceae, Unknown 72, and
Unknown 63. There are significant peaks in both Cheno-Am
and Malvaceae at the 15 foot level. The major feature of
the section profile is the abrupt shift in pollen domi-

nance at the 82 foot level.

Comparison of Study Sections

In the most general terms, the entire Valley sec-
tion and the lower Shortcut and Rockville sections are
characterized by pollen spectra of basically similar com-

jposition. The spectra are dominated by Picea, Ulmus, and

 

Pinus, with other types such as Abies, Tsuga, TCT, Alnus,
‘getula, Carya, Castanea, Fagus, Juglans, Pterocarya, and
(Quercus comprising the remainder of the total count. This
type of pollen spectrum is characteristic of all of the
samples from which Graham was able to isolate pollen and

spores (1965). Immediately below a prominent white ash

50

layer in both the Rockville and Shortcut sections, a
change in the nature of the pollen spectrum occurs. Pigga
pollen, a dominant in beds below this level disappears
entirely or becomes very much reduced. Abigg and Tsuga,
never as abundant as Pigeaj disappear entirely above

this critical level, as does the pollen of Betula, Carya,
Fagus, Liquidambar, and Juglans. Other types, such as
TCT, Aggr, Castanea, and Pterocarya either disappear above
the critical level or persist at reduced numbers, while
others, of which Quercus, Populus, and Salix are examples,
may increase in numbers above the transition interval.
Pings pollen typically shows a gradual increase in
importance from older to younger sediments. Pollen types
such as the Compositae, Malvaceae, Chemo-Am, Unknown 63,
and Unknown 72, which are either absent or rare below

the transition zone assume a dominant role in the upper
part of both sections. Similar lithologies and a close
correspondence in the two pollen profiles would tend to
support the correlation of these two sections described
in Chapter III. The Valley section does not show such a
sudden change at beds assumed to be of comparable age

and the only point of similarity between the upper Valley
secmion and the upper portions of the Rockville - Shortcut
cxnmplex is the slight increase in the Compositae and
thiknown 63 at the very top of the Valley Section. Corre-
.lation of the beds immediately below the prominent ash

iLayer in the Valley section with the beds of the lower

51

Shortcut and Rookville sections must be approached with
some care. It is possible that the two Pigea peaks at
the base of both the Shortcut (107 and 72 feet) and Rock-
ville (95 and 82 feet) sections may be equivalent to the
two peaks at 65 and 35 feet in the Valley section. The
pronounced peak in Alnus that occurs immediately prior to
the final Pigga peak at both Shortcut and Rockville may
be represented by the series of perturbations in the
Alngs curve at the 40 foot level in the Valley section,
but this is far from a secure interpretation. Another
alternative in relating the Valley sediments to those of
the Rockville - Shortcut sequence is to consider the
plant-bearing shales between 130 and 50 feet in the Valley
as a thicker expression of the complex and often highly
organic shale series at the base of the Rockville and
above the basal sand in the Shortcut section. Following
this interpretation, the earliest of the two Pigea_peaks
at Rockville and Shortcut would be equivalent to the
broad peak at approximately 160 feet in the Valley, while
the final Pigga peak at Rockville and Shortcut would
correlate with the sharp peak at 125 feet in the Valley
section. The significant Alngs peak just above 150 feet
in the Valley section would then be in the proper position
to correspond to the Alngg peak at the base of the Rock-
ville - Shortcut complex.

The shape of the various pollen profiles lends

weight to the hypothesis that the Valley section, from the

52

lignitic series at approximately 150 feet to the thin
green shale below the prominent white ash at approximately
35 feet, probably represents the same interval as the 82
to 62 foot sequence at the Shortcut section. The base
of the Rockville, from 97 to approximately 80 feet may
include only the upper portion of this interval. There
are shale zones at the base of both the Rockville and
Shortcut sections which have much the same lithology and
macrofossil content as the thick fossiliferous shale
sequence in the Valley section, and the fact that this
problematical sequence of beds is located immediately
above a thick sand at both the Shortcut and Valley sec-
tions tends to support this latter hypothesis for corre-

lating the Shortcut-Rockville and Valley sections.

CHAPTER V

PALEOECOLOGY

The quality of the inferences which can be made
regarding the paleoecology of a fossil flora can generally
be considered to be dependent on four factors:

1. The reliability of taxonomic assignments
and the level to which they are made.

2. The extent to which the ecological require-
ments of the extant equivalents of the
fossil taxa are known.

3. The size and diversity of the flora.

4. The relationship between the relative
abundance of the plant parts studied, i.e.,
leaves, stems, fruits, pollen grains, or
spores, and the relative abundance and
spatial distribution of the parent plants.

The first factor, the reliability and level of

taxonomic assignments within the flora, is extremely
critical and the importance of this phase of a study
cannot be over-estimated. Identification of Tertiary
fossil material is always more difficult and the conclu-
sions more tentative than would be the case for equivalent

Imodern material. This is due to several factors, includ-

ing the quantity and quality of the fossil material and

53

54

our inadequate knowledge of the equivalent organs or
structures in modern taxa. The pollen of modern forest
trees from temperate areas can usually be assigned to a
genus, but rarely to a species. The same is true of equiv-
alent Tertiary material. Herbaceous pollen may be assign-
able to the generic level, but more commonly a family
designation is the best that can be achieved and often
this can be doubtful. The primary limitation to the
study of most pollen types is the limited number of char-
acters available for assessment when the light microscope
is used. The size and variability of a taxonomic group
is often directly related to the degree of precision which
can be expected in the identification of pollen grains
within the group. If corresponding fossil material is
degraded in quality due to poor preservation, identifica-
tion with a modern group becomes even more difficult. The
problems involved in the nomenclature of Tertiary pollen
grains and spores are discussed in the chapter on the
systematics of the flora.

The second factor, the extent to which the
ecological requirements of the presumed equivalents of
the fossil taxon are known.intergrades somewhat with the
first factor considered. Obviously, the ecological
requirements of a species are likely to be more easily
categorized and somewhat less generalized than those of
a genus, especially if the higher rank is quite large

and.variable in its composition. Similarly, the ecological

55

requirements of a genus are more useful in ecological
reconstruction than those of a whole family. For most
large families, only the most general statements regard-
ing ecological trends can be made.

When ecological data are available for a given
taxonomic group, they are more likely to consist of
patterns of distribution within a generalized climatolo—
gical-geoqraphical context rather than a detailed analysis
of ultimate limiting factors operating to produce the
present distribution of the group.

A uniformatarian approach to the problem of
paleo-ecological synthesis may also create unique pitfalls
in any analysis. The modern distribution of any particu-
lar taxon is the end product of a continuous interaction
of plant and environment in both time and space. Since
the modern distribution pattern is a result of the complex
interplay of environment and the various tolerance levels,
dispersal capabilities and Opportunities, and the continu-
ous modification of the genome through the action of
natural selection on Various mutations, the question can
and must be raised as to what extent the distributional
patterns of modern taxa adequately reflect the equilibria
likely to have been established at some time in the past.
The fact that much of the temperate vegetation of the
northern hemisphere is either recently recovered or still
recovering from the geologically recent glacial—fluvial-

pluyial episodes of the Pleistocene, suggests the need for

56

caution in applying recent distributional phenomena as

an infallible Rosetta Stone to the problems of Tertiary
Ipaleoecology. The equilibria represented by the distri-
bution on some modern taxa may not be entirely typical.
Axelrod (1941) suggests that ecotypic variation in many
Tertiary taxa may have been somewhat greater than at
present and that this may serve to explain some otherwise
anomalous combinations of taxa that comprise some Tertiary
plant communities.

The size of the flora is also very important. A
large aggregation of taxa with a degree of ecological
compatibility is more useful than a small florule. A
large flora is also more likely to reveal some of the
nuances of community structure than a comparatively
depauperate assemblage. A large flora with a degree of
ecological compatibility also makes it easier to assess
the position of certain taxa which might have a wide
ecological amplitude or requirements of an unusual nature
which might otherwise alter the interpretation of the
entire assemblage. The presence of a nominally warm—
temperate form in a flora of otherwise cool—temperate
aspect suggests two alternatives. Either we can shift
the whole flora to a warm-temperate setting to satisfy
the presumed requirements of just one or two taxa, or we
can postulate the existence of more sheltered micro-
habitats or the existence of an ecotype that is somewhat

more cold tolerant. The latter approach certainly appears

57

to be the sounder of the two when only a small number of
anomalous forms are present.

Drawing inferences based on the shift in relative
abundance of the various taxa in a flora is a complex task
and one in which the interpretive values are different for
different types of material, such as leaves, seeds,
fruits, pollen grains, or spores. The problem, in a
narrower sense, of how the number of pollen grains of
various taxa in a sediment reflect the source vegetation
is highly complex and, as yet, not amenable to rigorous
evaluation. In practice, interpretations of pollen pro—
files and spectra are often subjective in that the repre-
sentation of the various palynomorph taxa is a complex
function of all of the following factors:

1. Pollen and spore production in the source
areas.

2. Transportation of the material by means of
various vectors to the basin of deposition.

3. Sedimentation and initial preservation of
the palynomorphs.

4. Post-depositional modification of the
pollen suite.

5. Methodological bias introduced by the
recovery techniques.

6. Bias and systematic errors introduced by
the means chosen to display the data.

The complex nature of the interrelationship of
these factors means that there is no unique interpretation
regarding the nature of the source vegetation as judged

from the pollen data alone. Large shifts in the quantitative

58

and qualitative composition of the flora can indicate
general trends which appear probably on the basis of our
knowledge of present vegetation, but a large element of
uncertainty exists in every case. If subsidiary evidence
in the form of fossil leaves, fruits, or wood is available
for the same deposit, the overall reliability of any
judgements is increased, due in part to the fact that the
distributional controls for other plant parts may not be
the same as those operating on pollen grains and spores.
Uncertainty regarding identifications within the flora
may also be reduced if the presence of a given taxon is
supported by data from several different plant parts. The
extensive data which are available on the composition of
the Sucker Creek macroflora provides a valuable cross-
check on the data derived from the pollen and spore flora
and will be injected into the discussion whenever appro-
priate.

The first step in any ecological analysis of a
fossil assemblage is to categorize the elements of the
flora in terms of the general type of plant communities
in which their modern counterparts would be likely to
occur. This problem is complicated somewhat, as mentioned
earlier, by the fact that most of the palynomorphs could
only be identified to the level of genus, while others
were only assignable to families or groups of families.
Any characterization of the community types must therefore

be somewhat broad in scope. Figure 9 is an attempt to

59

mmnmoeecfl Ax.
may mmnmoaecfl A

IQOHQ mwB coflpmosw CH coxmp ecu mopmoHpCH AI.

.mHmQEsc pcmoeMHcmflw CH ucmmoum manmnoum mp3 coxme opp
cm mean: .mHmQEDQ owned ca pop #59 cucmmmum wanmnonm mmB coxmp

meE coeummsv m .mmmp muflcsEEoo cm>flm m Ce pcmmoum poc wane

Swap é

.munofiflpom xoouu Hoxosm

one cfi pcsom momhu coaaom popooaom mo COHpMOHMHmmMHo HMUflmoHooo pomflamumcom «1|.m ousmem

><I><

IC‘ol
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IO-II
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x I
x I
x I

xcnl

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(‘0 (‘0

nox><l

n.

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IC‘OI

o.

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X><nol

 

ummnom asuom
mcmucoz \mfiuflmum
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ummnom ummuom

mmoam
who

oQon pamHEOuuom

Demo:

ummnom

Demo:

semam mEm3m swam: paom

IUOOHh

no
oxen

memoseasmoq
omoomnucmnmee

10mmUMHpomocmsu

mmocHEmnw

mmuflmOQEou

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momflmflmm

coamdemuow

 

 

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matfisnrom

 

Hmnfimpadmaq
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60

classify the more common components of the Sucker Creek
microflora in terms of the presumed ecological affinities
of the source plants.

Taking the flora as a whole, there are several
distinct community types whose presence is indicated.

Each of these will be considered in detail.

Lakes or Ponds.--Potamogeton and Nymphaea are both

 

 

genera which are indicative of ponds or lakes. In addi-
tion to these plants, algal material referable to the

genus Botryococcus, as well as a number of unassignable

 

algal cells and cysts, would strongly suggest the presence
of impounded water in some configuration. Botryococcus

is restricted to such environments and it is present in
virtually all productive samples from all three study
sections. The nature of the biotic evidence supports the
hypothesis that most of the plant-bearing sediments accu—
mulated in lacustrine basins, despite the fact that
Kittleman (1962) considers most of the Sucker Creek sedi—
ments to have been fluviatile in origin. The individual
basins may have been limited in extent but they must have
been widespread in their occurrence to account for the
lithological correlations which it is possible to make.
Detailed study of the organic-rich sediments of the Valley
section indicates that there were periodic incursions of
coarser clastic material in the form of sand and mica
flakes. Although it is possible that such material could

accumulate in the marginal swamps associated with a single

61

large lake, periodic breeching of natural levees in a
series of oxbow lakes closely associated with a large
river system would appear to provide a more satisfactory
model which would account for both the lacustrine and

fluviatile nature of some of the Sucker Creek sediments.

Marshes.--Small numbers of Typha_pollen grains are
the only unequivocal evidence available for the existence
of this community type. The poor representation of these
pollen grains would indicate that large stands of the
plant were not common and it seems reasonable to envision
small marshy pockets, almost certainly associated with
the oxbow ponds or lakes, as the likely habitat for the

source plants.

Swamps.--Pollen grains of the Taxodiaceae are the
only common type which are at all characteristic of this
plant community. The presence of lignites, organic silt
and mudstones, and highly organic shales at various
levels in the study sections provides subsidiary evidence
for the existence of localized swamps in which organic
material was accumulating. It seems possible that both
swamps and marshes were a natural consequence of the
hydrologic succession developing from the ponds or lakes

discussed previously. Equisetum, commonly found in many

 

of the Sucker Creek sediments, may have played a role in
the filling in of lake margins just as it does in parts

of North America today.

62

Floodplain.--The existance of a major river system

 

in the Sucker Creek area strongly suggests the existence
of floodplain habitats. Populus and §E$i§ would almost
certainly be important members of such communities.
Abundant leaves of Platanus from several localities, most
notably the Maple Ridge site, provide subsidiary evidence.
Leaves of §Eli§ are extremely common at all localities.
Aigug was probably associated with either a floodplain or
lake-side community, for at times extremely large clumps
of several hundred pollen grains can be noted in the
organic facies. Such large aggregations suggest that
alder clumps grew close enough to the water for entire

catkins to drop directly into the basin.

Mesic Bottomland and Slope Forest.--The division

 

between these two forest types is not clear and a grada—
tional situation probably existed. These two forest
types appear to have served as a source for the majority
of the plants indicated from both the macrofossil and
microfossil record. A diverse assemblage of maple,
chestnut, beech, sweetgum, oaks, basswood, walnut and elm
probably covered much of the lowlands, extending upward
onto adjacent slopes. Soil and moisture patterns and
varying slope exposures probably served to partition off

the complex into a mosaic of community types. Podocarpus

 

and Cephalotaxus, two genera native to the mountains of

 

central and western China, are new records for the flora

63

and probably occurred as very rare plants in the lowland

or slope forest.

Dry Slope Forest.--Drier sites, particularly those

 

which might result from complex topographic relief, might
be expected to support a somewhat less mesic oak-hickory
forest complex which might tend toward pine dominance on
sites where moisture was more limited. The Pine locality
(Figure l) is characterized by large numbers of pine
needles, indicating that this genus may have formed
extensive stands, but the sites were probably removed from
the depositional basins at most locations since the plant
is otherwise quite rare in the macro—fossil record. It is
also possible that pine, in company with oaks and hickories
may have played a successional role in the development of

a more mesic forest community.

Xeric Communities.--The existence of certain xeric

 

community types, either local or regional in extent, is
suggested by the presence of pollen types such as the
Compositae, Gramineae, Malvaceae (cf. Sphaeralcea) Chenopod-

iaceae-Amaranthaceae (cf. Sarcobatus), and pollen, thorns,

 

and pods referable to the Leguminosae. The presumed
distribution patterns and significance of this community
type will be discussed in detail when the overall patterns
suggested by the stratigraphic pollen sequence are con-

sidered in detail.

64

Montane Conifer Forest.——The presence of large
numbers of spruce pollen grains in company with those of
fir and hemlock suggest a community type of boreal aspect.
Since the bulk of the flora is decidedly temperate,
although probably cool temperate, in aspect, the only
reasonable model that would permit the close spatial
association of a temperate deciduous forest and a forest
of boreal affinities is the existence of diverse topo—
graphy in the immediate area of the depositional basin.
Although hemlock often occurs in relict enclaves in the
Appalachians today (Braun, 1950), its most logical habi-
tat in the Sucker Creek landscape was as a part of a slope
transition forest tending into a spruce-fir forest at
higher elevations. Aigus and Betula may have been part
of this complex. It is also possible that aspens may
have grown in this upland forest, but the fragile nature
of Populus pollen makes it likely that most of the Sucker
Creek Populus pollen was derived from cottonwoods along
a floodplain near the depositional basin.

This classification of the macro-community types
indicated by the Sucker Creek pollen record is completely
compatible with the broad regional picture outlined by
Axelrod (1968) who recognizes the following major forest
types from the Miocene of the Snake River basin:

I. Sub-alpine Conifer Forest
II. Conifer-Hardwood Forest

III. Mixed Deciduous Hardwood Forest

65

In his treatment of the Miocene Trapper Creek flora from
southern Idaho, Axelrod (1964) recognized virtually the
same array of major community types outlined in this chapter.
Since the Trapper Creek flora consists primarily of fossil
leaves, which presumably have limited dispersal capabilities,
the consistent representation of the upland conifer forest
suggests that the Trapper Creek sediments were deposited at a
somewhat higher altitude than those of Sucker Creek, but that
the regional flora may have been somewhat similar.
Patterns of Vegetation Change
During Sucker Creek Time

During the earliest part of the depositional inter-
val, represented by the sediments at the base of the Valley
and Shortcut sections, the pollen profiles suggest an
extensive development of the mesic lepe and bottomland
forest types. A rich forest of oak and elm with maples,
hickory, chestnut, beech, sweetgum, walnut, basswood, and

wingnut (Pterocarya) probably covered much of the valley

 

floor and extended upward onto adjacent slopes. The
record of aquatic vegetation is meager and this, coupled
with the coarse nature of the sediments suggests that
deposition was probably confined to well—defined stream
channels with relatively well-drained conditions through—
out much of the valley bottom. The scarcity of Sgiii

and possibly P0pulus pollen suggests that true floodplains
may have been somewhat rare. The scarcity of taxodiaceous

pollen suggests that swamps were not common. Somewhat

66

drier conditions probably existed on some slope exposures
with oak-hickory forests grading into pine stands. These
drier areas were close enough to permit relatively large
quantities of pine pollen to enter the record, but not
sufficiently close for deposition of other pollen types
indicative of similar conditions. A montane conifer
forest of spruce, fir, and hemlock undoubtedly covered
extensive upland areas, extending down quite far toward
the depositional basin. The fact that these pollen types
are large and heavy, particularly the grains of fir,
suggests that the high percentages contributed by these
genera are a result of wind and water transport from
extensive stands not far removed from the sites of sedi-
ment accumulation.

The abrupt change in the nature of the Valley and
Shortcut sediments from coarse sand to shales and highly
organic mudstones and siltstones suggests that extensive
impoundment of water into ponds or lakes occurred at the
time the sediments approximately half—way up the Valley
section were deposited. The introduction into the pollen

record of Potamogeton and Typha support the hypothesis that

 

extensive quiet water conditions existed at this level in
the section. At this point there begins a gradual rise in
the percentage of taxodiaceous pollen suggesting that normal
hydrologic succession was beginning to fill in the impound—
ments, producing swamps. An increase in the percentage of

willow pollen, followed by a later increase in Populus, along

67

with a series of pulse-like increases in oak, might well
represent a more extensive flood—plain component in the
vegetation of the valley floor. The entire deciduous
forest mosaic was probably developed on a more poorly
drained landscape than had been the case previously and

many small lakes may have been present.

These lakes began to fill with both organic and
detrital sediments, producing swamps and wet areas of
increasing extent as the area of open water was reduced.

The relatively short persistence of Potamogeton in the

 

central part of the sequence, coupled with a slight
increase in cattail and a continued rise in the taxodia-
ceous pollen percentage all serve to indicate that such

a successional sequence was occurring on the valley floor.
Alder was probably part of this sequence and the major
Aiggs peak in all sections was probably a result of exten—
sive development of shrubs on the wet margins of the lake
basins. The rather sharp drop in spruce pollen which
appears to be coincident with the alder peak in both the
Valley and Shortcut sections requires careful analysis.

In general, the deciduous pollen types drop only slightly
or remain unchanged, suggesting that the rather precipi—
tous drop in spruce pollen may reflect an upward with-
drawal of the montane conifer forest, rather than a mere
depression of the spruce curve due to the interactive
nature of relative pollen diagrams. It is possible that

there was a slight warming trend during this interval,

68

but this is hard to determine. The relative extent of
both the montane conifer forest of the adjacent uplands
and the deciduous forest of the valley floor undoubtedly
underwent oscillations of varying magnitude depending on
the local climatic pulsations during the interval in
question. During the time represented by the upper third
of the Valley section strata taxodiaceous swamps were quite
extensive locally, probably as a result of filling of the
local ponds or lakes. These extensive areas of shallow-
ing water with a steady accumulation of mud and organic
material resulted in ideal conditions for the preserva-
tion of fossil leaves and it is from these beds and

their presumed equivalents in other isolated localities
that the finest macrofossil record of the lowland
deciduous forest complex is preserved. Figure 10 is a
list of the various macrofossil taxa which are character-
istic of this level in the section. It is also interest-

ing to note that the finest specimens of Glyptostrobus,

 

complete with attached male and female strobili, occur
in these shale beds in the Valley section at the same
stratigraphic level as the main peak in taxodiaceous

pollen.

Aside from the presumed oscillations in the rela-
tive extent of the lowland deciduous and montane conifer
forests and the apparent hydrologic successional
sequence occurring in and around the depositional basins,

the overall vegetation mosaic suggested by the pollen

69

 

 

 

 

 

 

 

 

 

 

Lower Upper
Genus Section Section

Equisetum X X
Cephalotaxus X

Picea X*

Pinus X* X*
Glyptostrobus X* ?*
Thuja X

Cyperacites X* X*
Typha X* ?
Acer X* X*
Ailanthus X

Alnus X* *
Arbutus X

Betula X* X
Castanea X* X*
Cedrela X X
Cornus X

Crataegus X

Diospyros X

Fagus , X*

Fraxinus X

Ilex ?* X*
Mahonia X* X
Nyssa X*

Oreopanax X
Ostrya X

Platanus X X
Populus X* X*
Ptelea X

Quercus X* X*
EYfipHEficarpos x
Salix x* X*
Tilia X*

Ulmus X* 9

Figure 10.--A list of selected Sucker Creek macrofossil

genera and their occurrence in the upper and
lower portions of the composite regional sec—
tion. An (X) denotes the presence of the
genus while a (?) indicates uncertainty due
to poor preservation and a limited amount of
material. An asterisk (*) indicates that
pollen of the taxon also occurs at the indi-
cated level. The list was compiled from
Graham (1965) and material in the Michigan
State collections.

7O

preserved in the Valley and lower Shortcut and Rockville
sections appears to have been relatively consistent in
composition.

The profound change which occurs in the nature of
the pollen curves in the lower Shortcut and Rockville
sections implies a significant change in the nature of
the source vegetation. As previously stated, the pollen
flora prior to the dominance shift is perfectly in
accord with that of the entire Valley section, but in
the green shale overlying the last of these beds the
nature of the pollen flora is abruptly changed. Spruce
pollen, previously so abundant,is reduced to insignifi—
cance or disappears entirely. Fir and hemlock pollen
disappear as well. The pollen record of the montane
conifer forest ceases to have any significance for the
remainder of the sedimentary interval studied and it seems
reasonable to assume that the entire forest type dis-
appeared from the general area in which deposition was
taking place. The deciduous forest growing at lower
elevations appears to have undergone many changes as well.
Elm, which had previously dominated the deciduous tree
pollen complex disappears entirely, as do other mesic
forest types such as birch, hornbeam, chestnut, beech,
sweetgum, and walnut. Wingnut (Pterocarya) disappears
from the Rockville area but persists in much reduced num-
lmers at the Shortcut site. Alder and taxodiaceous pollen

axre both present, but at reduced numbers. Oak pollen may

71

be somewhat reduced in importance or may even increase,
while willow, poplar, and maple also persist. The over-
all picture is one of reduced diversity in the deciduous
forest component with the remaining types quite possibly
associated closely with the drainage system. The local
lowland flora may well have consisted of a riparian
community with willows, poplars, maples, oaks, and syca—
mores as the major components. The latter is not present
in the pollen record but its leaves are a common fossil
of beds assigned to the upper portions of the Rockville-
Shortcut complex and their equivalents. Figure 10 con-
trasts the somewhat limited macroflora of the beds of

the upper part of the composite section with those of

the lower section. The preponderance of willows, syca—
mores and oaks, particularly of the scrub—oak type,
support the hypothesis that the upper Rockville and Short~
cut beds record the presence of a comparatively depau—
perate flora of riparian aspect. Swamps were still
present and a number of exotics, such as Cedrela and

Glyptostrobus, continued to grow in the area, but in

 

general, the diversity of the woody forest vegetation was

:much reduced.

An entirely new complex dominates the pollen above
the transition level, indicating that a new series of
cxnmnunity types was becoming important in the region.

I; variety of composite pollen grains, including a high

 

Exarcentage of grains of sagebrush (Artemisia), pollen

72

of the Malvaceae, including one type resembling

Sphaeralcea, and the pollen of the Chenopodiaceae-

 

Amaranthaceae strongly suggest a herbaceous component of
decidedly xeric aspect. Pollen and thorns assignable to
the Leguminosae and the pollen of grasses reinforce the
concept of distinctly xeric communities that were pro—
bably somewhat removed from the stream valleys but still
close enough to dominate the record at two of the three
localities. The overall aspect of the region at this
time may have been very much like that of the same area
today. The dominant vegetation of the drier lowlands is

sagebrush (Artemisia tridentata) and cheatgrass (Bromus

 

 

tectorum), but if one travels from 3500 feet, typical

 

of the fossil localities, to 6-7000 feet in the Owyhee
mountains in the Silver City, Idaho area, the vegetation
shifts from sagebrush dominance up through a juniper
transition zone into a spruce forest zone on the higher
peaks. In the case of streams however, the local vege-
tation consists of a riparian flora of willow, poplar, and
oak, as well as numerous herbs, in very close association
with the drier sagebrush community and within site of
the spruce forest of the upland. A similar situation,
IMith a somewhat more diverse riparian community, may well
have existed in the area in late Miocene time.

Pine pollen is very important in the upper part of
tine Rockville - Shortcut complex. The type characteristic

of the lower part of the section is replaced by several

73

new types above the transition interval where the overall
importance of pine pollen appears to gradually increase,
barring small fluctuations, as one approaches the top of
both the Rockville and Shortcut sections. The very high
percentages, occurring in a sample collected several feet
above the top of the measured Rockville section, corres-
pond in their stratigraphic position to the beds of the
Pine Locality (Figure l) where numerous fascicles of pine
needles have been found. A number of pine species were
probably present in the area at this time occupying sites
of varying elevation and exposure depending upon the
tolerance levels of the various species.

The abrupt change in the nature of the pollen
record in both the Rockville and Shortcut section
undoubtedly represents a significant change in the nature
of the source vegetation as outlined previously. Before
the regional significance of this change can be assessed
however, three factors must be considered:

1. How much time was required for the shift
in vegetation types?

2. What was the lateral extent of the modi—
fied community mosaic?

3. How long did the modified community struc—
tures persist in the area?

These questions are all critical to any discussion of the
Imechanism and significance of the observed shift in pollen
dominance .

The amount of time required to bring about the

sflmift is extremely important. The change may have been a

74

gradual one with the vegetation responding to long-term
changes in climatic patterns, or it may have been rather
abrupt. As previously stated, the observed shift in the
pollen curves occurs abruptly in the sedimentary record
but this in itself is not conclusive. A gradual shift
may appear to be abrupt if there is a depositional
hiatus or diastem in the sedimentary record. Unfortunately,
there is little stratigraphic data which can be brought
to bear on the problem. No evidence for such a deposi—
tional break was observed in the course of measuring and
sampling the study sections. In the absence of evidence
to the contrary, it must be assumed that there is no
prominent break in the record at the critical level.
Sedimentation may have been slow, but in geological terms
the time interval during which the shift occurred cannot
have been very great. Such a comparatively rapid shift
would appear to favor a mechanism involving the action
of local factors rather than the slower, long—term
phenomena associated with widespread cliseral changes.
The question as to the lateral extent of the vege~
tation change can be answered with more precision. Both
the Rockville and Shortcut sections clearly show the
shift, while the Valley section, located to the south
(Figure 1), shows little change at levels assumed to be
(of comparable age. There is a slight increase in some
xeric forms, but the major displacement of the more mesic

forest elements is not observed. If the beds at the top

75

of the Valley are contemporaneous with the critical

strata at Rockville and Shortcut, then the changes occur-
ring in the vegetation to the north are only slightly
reflected in the sediments in the Valley area. It was not
possible to locate conformable beds above the white ash
layer in the Valley so that it cannot be said whether the
shift in pollen dominance was a progressive one which
worked its way south at a later time or if the situation
recorded in the upper Valley beds and the middle of the
Rockville-Shortcut complex represents a fairly stable
readjustment of the aerial extent of the various community
types.

There is no pollen evidence available to attempt
an assessment of the length of time the new pattern of
vegetation distribution may have persisted in the area.
There is some indirect evidence available from fossil
mammal remains from the type section of the Sucker Creek
Formation, presumably of a somewhat younger age than the
composite study sequence. According to Kittleman (1962)
the mammals represent both streamside browsing and
‘various grazing types. Such a fauna would be perfectly
consistant with the environment postulated on the basis
of the upper Rockville — Shortcut pollen profiles, but
*would be somewhat anomalous in the mesic deciduous—
xnontane conifer forests of the early part of the sequence.
The mammalian evidence would seem to provide a tentative

basis for assuming that the modified riparian - xeric

76

complex of the upper part of the study sequence probably
persisted at least until the end of Sucker Creek time

(sensu latu).

 

In summary then, the change in dominance in the
local flora occurred during a relatively short interval.
The change was synchronous in an east-west direction but
is only slightly reflected in the record an equal distance
to the south. There is evidence that the change in the
nature of the flora may have persisted at least through
the remainder of Sucker Creek time. The principal ques-
tion at this point is whether or not the observed changes
in the nature of the vegetation in the Sucker Creek area
are consistent with any of the hypothesis which have been
advanced to describe the patterns of climatic change in
the Pacific northwest during middle and late Tertiary
time. Since most of the studies of fossil plants in
western North America have been oriented toward recon—
structing the environments under which the ancient floras
grew, there is a great deal of data which can be brought
to bear on the problem. Two principal theories regarding
late Tertiary climatic trends have emerged. The first of
these, summarized by Axelrod and Bailey (1969), theorizes
that there has been a steady decline in effective temp-
eerature throughout the western United States since
Imocene time and that the regularity of this decrease is
iJTterrupted at intervals by very sudden drops in effective

txunperature which are attributed to uplift activity.

77

Graphs which they have prepared for both eastern Oregon
and western Nevada are reproduced in Figure llA. These
graphs were prepared on the basis of an exhaustive ecolo-
gical analysis of a large number of Tertiary floras from
the areas concerned. In Axelrod and Bailey's view, the
major cause of variation in composition between floras

of similar stratigraphic position is a result of altitu—
dinal differentiation and the thrust of their paper is
that a careful analysis of the composition of a flora may
be used to determine the elevation at which the source
plants were growing. Axelrod applies this technique in
his treatment of the topographic history of the Snake
River basin (1969).

The second theory, perhaps best exemplified by
the work of Wolfe and Hopkins (1967), hypothesizes that
the pattern of temperature change from Eocene to the end
of the Pliocene was a somewhat aperiodic oscillation from
periods of relative warmth to significantly cooler inter-
vals. The latter part of their paleotemperature curve
for northwestern North America covering the Oligocene and
Miocene is reproduced in Figure 118. The curve is con—
structed on the basis of a morphological analysis of the
various leaf types using as evaluative criteria many of
the observations originally made by Bailey and Sinnott
(1915, 1916). Such a morphological approach to paleo-

environmental analysis was initially used by Chaney and

78

 

 

 

 

 

 

 

 

 

 

 

 

 

(A)
OLIGOCENE MIOCENE
0
3 —
0 60~\
0 A" -..“‘l'/- [\l a
O. - N~”‘JVC»C!Q
E \
0 A ._ ‘ “g-
.— u- R
O
a); v '7 “cm LIE- 19:43: - a I: H‘s‘q‘k :; ~ ...
: I..- 4;’R%WL ‘7 “'3? 134:4
3 "‘ -.._z-_._._h . -13
E 5 5 -—
(3 I
s mmer
"we: ”3‘23?" OLIGOCENE MIOCENE
m IE d
t— a: 2
2 <( < in
0'- I-
x NJ 3 ifp§§. g
< a. .I~ It“; ’5’ {at}.
a 2 l h f \r.
“J .1. If ’ \zh.
.— \\ / l 4
u. \‘wfim'f/ \‘n y?”
m .J g g
H (3 u:
< O a.
.i a:
u 2
o g 0.1
O 2 I—
L’ m
.—

 

 

 

 

 

 

F|GURE II. Oligocene—Miocene
on the basis of
I969)and (8) leaf

(A) ecological

temperature

trends postulated

analysis (Axelrod and Bailey,

morphology (Wolfe and Hopkins, I967).

 

79

Sanborne (1933) and the method is discussed in some detail
by Dorf (1969).

In addition to temperature, another factor which
must be considered for floras of late Tertiary age from
both the Columbia Plateau and Great Basin provinces is
the ever-decreasing rainfall resulting from the developing
rainshadow which was a consequence of the gradual uplift
of the Cascades to the west during the middle and late
Tertiary time. Whatever the pattern of temperature change
during this interval, a pattern of decreasing moisture
availability must be superimposed upon it in order to
arrive at some approximation of the general climatic
regime under which a flora such as the Sucker Creek must
have grown.

In comparing the nature of the change observed in
the Rockville and Shortcut sections with the relatively
uniform temperature and moisture declines which are a
consequence of Axelrod and Bailey's model, it is apparent
that major local factors would have to come into play to
cause the shift in pollen dominance observed in the
Sucker Creek sediments. In contrast, the temperature
fluctuations inherent in Wolfe and Hopkin's model could,
in company with declining moisture availability, provide
sufficient climatic variability to be an important factor
in causing the type of vegetation changes observed in the
Sucker Creek area. The low temperature interval in late

Miocene time (Figure 11B) is consistent with the presence

80

Of a montane conifer forest in close proximity to a low-
land deciduous forest of possible cool temperate aspect,
characteristic of the lower part of the composite study
section. Under such cool conditions, provided there was
sufficient thermal equibility throughout the year, the
ever increasing-moisture stress brought about by the
uplift of the Cascades would have only a limited effect
on the flora. An abrupt rise in temperature, such as that
indicated on the graph following the late Miocene minimum,
particularly if accompanied by a decrease in equibility,
would certainly cause moisture availability to become a
factor of increasing importance. As long as the various
plant communities were able to maintain their integrity,
microclimatic amelioration may have been sufficient to
overcome the gradual increase in moisture stress, but
any local events which would disrupt community integrity
might well serve as a triggering factor resulting in a
comparatively sudden shift to communities of decidedly
more xeric aspect. It seems quite possible that the fac—
tors which could cause such local disturbances might be
linked to the volcanic events which produced the sediments
iJi which the flora was preserved. One such effect might
be the damming and diversion of subsidiary drainage
channels, resulting in pronounced moisture deprivation
le areas downstream from the diversion.

A second and probably more significant factor might

Ihave teen the localized destruction of vegetation due to gas

81

venting and ash falls. Such an effect was noted by Dorf

(1945) in a study of the ash falls in the Paricutin area of

Mexico. He noted that most of the forest vegetation
within three miles of the cone was killed and that the
resulting ash blanket ruined cultivated fields within

the same radius. The extent to which the Sucker Creek
forest may have been affected would depend on many fac-
tors but it is quite likely that re—establishment of the
original vegetation on denuded sites might be much delayed
and, in fact, might never occur if water availability were
sufficiently critical. The Valley section might repre-
sent a more protected site further from the source of

the ash where the original vegetation may have persisted
with little change. To what extent the vegetation was
altered over the entire region and whether we are observ-
ing just a small portion of a progressive decrease in the
extent of the mesic forest vegetation can only be deter-
mined from additional studies in the same area.

The pattern shown by the Sucker Creek pollen pro-
files would appear to be consistent with the somewhat
irregular temperature regime postulated by Wolfe and
Hopkins (1967) rather than the uniform deterioration
theorized by Axelrod and Bailey (1969). Both of these
models are, by necessity, highly generalized and the extent
to which short-termed variability played an important part
cannot be determined due to the limited "resolving power"

provided by paleobotanical studies within the region.

82

Situations such as that exemplified by the Sucker Creek
pollen sequence almost certainly represent the product of
the interaction of both local and long-term regional
climatic factors.

Viewing the patterns of distribution of the
various taxa from the leaf localities and comparing them
to the picture provided by the pollen record provides a
useful insight into the kinds of problems likely to be
encountered in studying middle and late Tertiary floras.
The relatively smaller number of taxa recorded from
localities such as Specimen Ridge (Quarry), Maple Ridge,
and the Pine Locality (see Figure l) is not a matter of
chance representation or poorer preservation characteris-
tic of these highly indurated beds, but is, in fact, a
faithful representation of the plants which were growing
around the local basins. They do not reflect the more
diverse flora of the lower part of the composite section
but rather the comparatively depauperate riparian assemb—
lage characteristic of the upper Rockville and Shortcut
sections. Although this is clearly evident when the
complete pollen profile is examined, it was not possible
for Graham to recognize this because the rocks of the
plant-bearing beds themselves are barren of pollen and
these were the only strata examined in his study (1965).

It is highly undesirable to consider the plants from
a number of florules to be representative of a single flora

unless a number of conditions are satisfied. First, the

83

relative stratigraphic position of all of the important
localities should be known. Secondly, the extent of
variation in the composition of the various florules must
be analyzed to determine, if possible, to what extent the
variation reflects normal variability in representation
and preservation or a significant difference in the nature
of the source communities. Examination of the pollen of
the leaf-bearing beds is not conclusive unless all
localities are represented by pollen spectra. Macrofloral
analysis provides a high degree of taxonomic resolution as
well as providing representation for those taxa that would
not otherwise appear in the pollen and spore record.
Microfloral analysis can however resolve changes in the
regional flora which might otherwise be masked in the
comparatively localized representation provided by macro-
fossil deposits. Both approaches to floral analysis are
complementary and both are preferred whenever possible.

It is encouraging that such synthetic approaches are
being increasingly applied to a number of the "well-
studied" Tertiary floras. The end result can only be a
more complete understanding of the patterns of distribu-
tion and dynamics of the vegetation of a particularly

critical period of earth history.

CHAPTER VI

SYSTEMATICS

Nomenclature

The problem as to what constitutes a suitable
system of nomenclature for Tertiary pollen and spores is
a complex one for which a number of alternative sugges-
tions have been proposed. An excellent account of the
current status of the problem is summarized by Traverse
'(1955). Tertiary material is particularly difficult in
a nomenclatural sense because it is amenable to treatment
by either or both of two diametrically opposed approaches
to the problem. The first approach is most commonly
applied to Paleozoic and Mesozoic pollen grains and
spores where the source plants can either be assumed to
be extinct or at best, only distantly related to extant
taxa. In such cases a system of form nomenclature, based
primarily on the morphological attributes of the pollen
grains or spores, can be used to good effect. Such nomen-
clature has been developed to a high degree of precision

and.is specifically provided for in the International Code

84

85

of Botanical Nomenclature (Lanjouw, 1966). Such systems
are particularly useful for the stratigraphic palynologist
and permit ready identification within the framework of

the system. A fossil spore "species" in such a system

is not equated with a biological species concept but is
simply a convenient level of classification which could
include one or more taxa of one to several ranks if it were
possible to examine the source plants with the same degree
of precision used for extant material. The vast literature
on Mesozoic and Paleozoic palynology uses form taxa almost
exclusively.

The second basic approach to the problem is
encountered in pollen analysis of Pleistocene and modern
materials where all of the pollen grains and spores
encountered can be assumed to have been produced by plant
species still recognized in the world's flora. The level
of taxonomic precision which can be obtained in such
studies is to some extent governed by the type of pollen
and spore material being dealt with and the goals of the
particular study. Studies dealing with the broad pat-
terns of Pleistocene forest development for example might
deal primarily with forest tree and shrub pollen identified
1x: the generic level, while herbaceous plants might be
identified only to family unless particularly distinctive
forms were present. Other studies, such as unraveling
tflue patterns of Pleistocene tundra development might require

careful evaluation of herbaceous pollen at the generic and

86

even the specific level where possible. In all cases how-
ever, the prevailing nomenclatural practice is to assign
the material to the lowest rank to which it can be
identified with certainty. Alder pollen which could not
be assigned to a modern species would be called Aiggs or
élEEE sp(p). Under no circumstances would an organ species
be created to cover the pollen grains, for it is obvious
that they are derived from a modern taxon already described
under one or more binomials. The creation of a separate
binomial to cover the pollen alone would be superfluous
and such a practice would certainly be rejected by any
competent pollen analyst.

It is in the treatment of Tertiary material that
these two rational approaches often are ignored or are

altered in a most confusing fashion. Part of the problem

may be traced to the transitional nature of the Tertiary
flora. Although most families and many genera of modern
dicots are well established by Paleocene and Eocene time,
it is highly unlikely that many "modern" species have
persisted since the early Tertiary. Extensive analysis
(If late Miocene floras by Chaney and Axelrod (1959) indi—
cates that many of the temperate plants are either
morphologically indistinguishable or extremely similar to
extant species. By Pliocene time most gymnosperms and
woody dicots probably belonged to extant species. While the
case with herbaceous dicots is less well understood, due

to their poor representation in the fossil record, the

87

increasing weight of pollen evidence indicates that at
least many modern genera and virtually all the typical
herbaceous families were present by late Tertiary time
(Leopold, 1969). In View of this pattern of development,
a very persuasive case can be made for assigning most
early Tertiary palynomorphs to form taxa in view of the
uncertainty regarding the antecedents of the source
plants. Since the rates of evolution of different taxa
are likely to be different, numerous exceptions to this
general practice can probably be justified, but in general
assignment of angiosperm pollen from early Tertiary
deposits to form taxa would appear to be a sound practice.
An equally persuasive argument can also be made for
assigning late Tertiary palynomorphs to modern taxa when-
ever possible (see Traverse, 1955).

Unfortunately, the situation is made somewhat
complex by the existence of systems which attempt to
combine the virtues of the two basic approaches outlined
above. Systems such as that of Potonie', Thompson, and
Thiergart (1950) involve the extensive use of organ
genera which are linked etymologically with various
modern taxa. Genera such as Alnipollenites are created
to which any number of "species" may be assigned. Such
a name represents a legitimate organ genus in the sense
discussed by Schopf (1969) and is intended to indicate
that the pollen included within the genus has the charac—

'teristics of Alnus. The practice of applying such names

88

to pollen from a late Tertiary flora such as the Sucker
Creek is questionable at best. The genus Aiggs is
unequivocally present in the world's Miocene flora and

the problem is reduced to the rather simple question of
whether the pollen grains in question do belong to that
genus. If, in the opinion of a competent researcher the
material can be so assigned it is best referred to as
Aigg§_and not to an artificial construct. Most modern
plant taxa are rigorously described on the basis of their
floral morphology, yet few taxonomists would consider modern
binomials to represent "flower species" for the names

have a much wider connotation. A modern plant taxono-

mist would have little hesitation about identifying a

leaf of Aiggg for example and few Tertiary paleobotanists
would call a Miocene alder leaf Alniphyllites. Such a

leaf would be referred to as Aigg§_with the same confi-
dence that a pollen analyst would recognize dispersed
Aiggg pollen. The only realistic reason for assigning
material to an organ genus is if the identification is
suspect, and here we return to the nub of the problem. If,
in the case of our hypothetical fossil pollen, the material
cannot confidently be assigned to the genus Aiggg, only
two alternatives are possible. Either the material may

be described as a member of the Corylaceae with uncertain
generic affinities, or it must be assigned a form name.

In either case, the use of the name Alnipollenites is

Ipatently misleading and should be avoided. Such use of

89

organ genera and the distortions of form systems such as
the halbnaturlische system of Potonié imply a degree of
taxonomic precision which is not present. Placing the
pollen grains in question within the Corylaceae and
indicating the extent to which they resemble and differ
from Aiggs pollen is a far better alternative and clearly
states the degree of taxonomic uncertainty. If the
grains cannot be assigned to a family then the application
of a form name is certainly the only approach that does
not imply more than is warranted based on the nature of
the material.

Once the decision is made to assign the material
to the lowest taxon of the lowest taxonomic rank, the
problem of the application of binomials to fossil pollen
material arises. Traverse (1955) assigns most of
his Oligocene pollen to extant genera and erects new
specific epithets for each type. The use of such a
jprocedure in a flora such as the Sucker Creek where a
'well-studied macroflora is present provides a number of
unique problems. Using the pollen of Quercus as an
example, two or three distinct types of oak pollen may
1x3 recognized in the microflora but the status of these
tijas is difficult to evaluate since most modern oak
Exillen cannot reliably be assigned to specific rank. If,
after a review of the literature one were to decide that
all. three types of pollen were distinct from oak pollen

prenniously described, then one approach might be to erect

90

three new species within the genus Quercus to describe

the pollen in question. The subsequent problem

is two-fold. First, there are between four and six well
authenticated species of oak present in the macroflora.
Due to the nature of the material and its close resemb-
lance to modern species, assignments on the basis of the
leaves are likely to be fairly reliable. Since all of
these six species are likely to have produced pollen which
would enter the record, it becomes obvious that one or
more of our pollen "species" is composed of pollen pro-
duced by more than one "biological" species. Extensive
study of leaf material over the years has resulted in

the creation of fossil species which probably parallel

a modern population concept quite closely. In the

case cited above, there is no clear way

to separate the "leaf" Species from the "pollen" species
although the two represent entirely different concepts.
Rather than take a step backward and assign each type of
material in the flora a different organ designation, the
developing rationale has been to reserve binomials for
material which is subject to rigorous analysis and to

use less precise assignments to material that cannot be
analyzed with the same precision. As mentioned previously,
it is possible to assign the leaves to taxonomic categories
closely paralleling a modern Species concept and the use
of binomials is entirely apprOpriate. Twigs and acorns

caf oaks cannot usually be separated with such precision

91

and is usually the practice to refer to them simply as
Quercus Sp. or spp. thus avoiding an unnecessary prolifer-
ation of names. The pollen presents the same problem as
these less easily identified plant parts and rationally
can be treated the same way. Oak pollen can be assigned
to the genus Quercus and the various morphological types
discussed in terms of their probable or possible affini-
ties within the genus without creating "species" which
have little biological integrity.

Similar problems arise if the material is assigned
to pollen "species," within an extant genus, previously
described in the literature. The use of the same binomial
for material from two different floras implies a biolo-
gical equivalency despite the fact that the "species" is
based purely on morphological grounds. The morphological
species concept is the core of paleontological practice
in the widest sense, but is valid primarily in the frame-
work of a form or organ nomenclature. If a morpho-
species is erected within an extant genus, there is no
imay, based on the form of the name, to differentiate this
"species" from those erected on a firmer systematic basis.
:Lf a flora consists of several species, some of which
puzrallel and probably correspond to a modern population
cxnncept and others erected on morphological grounds, the

stxrtus of the genus within the flora becomes more confused

rather than clearer .

92

In order to eliminate such ambiguities as much
as possible, the following system will be adhered to in
treating the Sucker Creek palynomorphs. First, material
will be assigned to the lowest taxonomic rank where identi-
fication is reasonably certain, usually a genus. If the
pollen grains or spores resemble those of a still lower rank
but problems exist in that placement, they will be dis-
cussed under the designation of the higher rank. Pollen
grains or spores which were not identified to an extant
family or genus are treated at the end of the systematics
chapter under their survey designations. In the event
that the material assigned to a given family or genus is
widely known under a binomial or form designation, this

will be mentioned in the discussion of the taxon in

question.
Systematic Descriptions

ALGAE

 

Division CHRYSOPHYTA
Genus BOTRYOCOCCUS Kfitzing
(Plate 3-18)
The interconnected cup-like waxey bodies constitut—
11“; the remains of this alga are identical in every
respect to those of the extant species B. braunii. This
genus has not previously been described from the flora
altJuJugh it has been found in Tertiary deposits from most

cxnrtinents. Traverse (1955) gives an excellent summary

93

of the Tertiary distribution of the genus as well as dis-
cussing its pre-Cenozoic record. The genus has an exten-
sive fossil history and appears to have been one of the
prime constituents of boghead coals (Bertrand, 1927,

1928). Colonial masses of Botryococcus are the most

 

common fossils of non-vascular origin in the Sucker Creek
sediments and are often preserved when fossil pollen
grains and spores are either absent or highly corroded.
They appear to occur in small numbers in the fine-grained
organic beds of the Valley and lower Shortcut and Rock-

ville complex.

Location: Pb-9245-l V+4.7le4.8

Algal Remains of Uncertain Affinity
Tree}.
(Plate 3-16)

This cellular filament is morphologically similar
to those of various filamentous Chlorophyta but it can-
not.be stated with certainty that it is not a septate
lnycelium. Filaments of this type have not previously

been described from the flora.

Location: Pb-9211-1 V+4.6le0.0

Type 3
(Plate 3-17)

These filaments of spherical cells resemble those

of certain of the Nostocaceae in the Cyanophyta but such

94

a placement is tentative. Filaments of this type are a
new addition to the flora. They are comparatively rare.

Location: Pb-9l9l-3 V+6.2lel.5

$192.3.
(Plate 3-14)

These entities consist of short uniseriate fila-
ments with rounded cells at their ends. They compare
quite closely with hormogonia produced by members of the
Oscillatoriaceae in the Cyanophyta. They are found
throughout the study sections but are usually somewhat
rare. Remains of this type are a new addition to the

flora.

Location: Pb-9l96—1 V—2.9xH9.5

Tvpe 4
(Plate 3-9)

Only a single specimen of this type was noted dur—
ing the study. It may represent an algal hormogonium but

the assignment is highly tentative.

Location: Pb-9l96-l V+8.4xH25.9

FUNGI

 

The role and utility of fungal spores in palynology
:is discussed by Graham (1962) but in actual practice little
Luna is made of fungal material. The principal problem lies
le the identification of dispersed spores. The morphology
of’rmost fungal spores is so generalized that identification

txp.any'meaningful level is usually not possible. Somewhat

95

more complex structures such as sporangia, fruiting
bodies, or differentiated hyphae may be somewhat more
diagnostic. Fungal bodies are found throughout the study

sections and are among the more common palynomorphs.

Genus ALTERNARIA Nees emend Wiltshire

 

(Plate 3-11)

The characteristic conidiophores of this member
of the Monoliniales are the only fungal entities which
can confidently be identified to the level of genus.
According to Alexopoulos (1952) the genus causes leaf
spot diseases in several crops. Various leaf spots,
probably of fungal origin, may be noted on many of the
fossil leaves in the macroflora and it is possible that
the genus may have played a role as a leaf parasite in
the Sucker Creek forest. According to Johnson and
Sparrow (1961), members of the genus are commonly found
growing on submerged wood in fresh and mildly brackish
water. Pady and Kapica (1954) reported Alternaria
conidiophores in over 2 per cent of the air samples obtained
<3ver the open ocean. In view of these observations, the
genus is likely to be well represented in a variety of
deposits and its presence is not likely to have any

envi ronmental signi fi cance .

Location: Pb-9l9l-3 V-5.4xH27.0

96

Fungal Remains of Uncertain Affinity
Tree}.
(Plate 3-1)
Spores of this type are not common and appear to
be confined to organic sediments. The general aspect of

these spores is similar to that of Cladisporium in the

 

Monoliniales. Cladisporium is a genus of stem parasites.

 

Spores of this type have been previously described from
the flora by Graham (1965).

Location: Pb-9lS7-1 V+7.4xH15.8

$132 3
(Plate 3-2)

This body resembles the terminal chamber of an
elongate conidium similar to Type 19 illustrated in
Plate 3-12. This form is found in small numbers through-
out the section.

Location:. Pb-9157—2 V+5.6le4.8

Eras. .4.
(Plate 3-3)
This spore superficially resembles those of Type 7
(except that it lacks the fine wall markings. The biologi-
caJ.aaffinities are unknown. Spores of this type are
found in the organic beds of all sections studied.

Location: Pb-9157-l V-O.8le7.3

2292.5.
(Plate 3-15)

The botanical affinities of this body are obscure.

It occurs in the organic beds of all three study sections

and is easily recognized.

Location: Pb-9157-2 V+3.7xH25.6

m9
(Plate 3-7)
This body probably represents a two-chambered
ascus. Remains of this type are found throughout the
study sections.

Location: Pb-9158-1 V+4.lel6.l

$11921
(Plate 3-5)
The botanical affinities of this spore are unknown.
It is easily recognized by its somewhat tear-drop shape
and the fine radial striations on the wall. It is found
in the organic facies of all the study sections.

Location: Pb-9158-6 V+4.0le7.8

Type 9
(Plate 3-6)

This spore is a larger variant of Type 1 and may

also represent Cladisporium. Its distribution in the

 

study sections is essentially the same as that of Type 1.

Location: Pb-9157-6 V-l.9xH8.7

(Plate 3-4)
This type is comparatively rare and confined to
the organic facies of the study sections. It may repre-

sent a two-chambered ascus but this is a tentative

assignment.

Location: Pb—9158-7 V+9.6le3.5

Tree .13.
(Plate 3-13)

The botanical affinities of this interesting two-
chambered structure are unknown. The complex pore-like
perforations in the end walls may represent a dispersal
mechanism or they may have been produced as a result of

differential decay. Only a single specimen was noted.

Location: Pb-9165-6 V+7.3XH11.8

Trail.
(Plate 3-8)
Only a single specimen of this type was found and
its botanical affinities are unknown.

Location: Pb—9182-l V+8.3xH5.0

Type i6
(Plate 3—10)

These small spherical spores have a minutely

spinulate spore coat which is quite characteristic. They

undoubtedly represent the dispersed spores of some

99

basidiomycete. Spores of this type are rare but may be
found throughout the study sections.

Location: Pb-9186-l V0.0xH14.2

$1223
(Plate 3-12)
A single specimen of this type was noted. It
appears to be a septate conidium and its affinities are
probably with the Monoliniales.

Location: Pb—9211-l V+6.6xH23.4

Teal
(Plate 3-19)

Only a single specimen of this highly characteris-
tic form was noted in the course of the study. The
specimen was recovered from the lower Valley section and
its botanical affinities are unknown.

Location: Pb-9260-l V+5.4le3.7

100

Division TRACHEOPHYTA
Sub-division LYCOPSIDA
Genus LYCOPODIUM L.
There are two distinct types of Lycopodium spores
present in the flora. The types are morphologically dis-
tinct and would appear to indicate the presence of at

least two species.

219.21
(Plate 4-3)

The spores of this type measure from 35 to 45
micrometers from an apex to the center of the opposite
side. They are sub-triangular in shape and have a rugu—
late surface texture similar to the living i. inundatum.
This type of spore is a new record for the flora and it
is found in the Valley and lower Shortcut and Rockville

sections.

Location: Pb-9223-1 V+l.le21.3

2x22 .2.
(Plate 4-9)

These spores appear identical with the Lycopodium
spores previously described from the flora by Graham
(1965). They are sub-triangular in shape and measure 30
in) 40 micrometers from apex to the center of an opposite
side. The surface is strongly reticulate and the spores
appear similar in all respects to those of the extant i.

alpinum and i. complanatum. Spores of this type are not

101

common and occur in the Valley and lower Shortcut and

Rockville sections.

Location: Pb-9263-l V+10.4xH9.4

Sub-division PTEROPSIDA
Class FILICINEAE
Family OSMUNDACEAE
Genus OSMUNDA L.
(Plate 4-8)

Only a single spore referable to this genus was
found in the course of the study. The specimen was
recovered from the Valley section and it seems probable
that the source plants were present in only small numbers
and in particularly moist and favorable habitats. The
specimen is similar to a specimen figured by Graham (1963)
which he calls 9. claytonites. It is sub—spherical meas-
uring approximately 40 micrometers in diameter. The rays
of the trilete scar measure approximately 16 micrometers
in length. Spores of similar size and morphology have
been isolated from a variety of western Tertiary sediments
and.are commonly referred to as Osmundacites wellmanii in

the palynological literature.

Location: Pb-9322-l V+7.2xH12.7

102

Family POLYPODIACEAE
Genus POLYPODIUM L.
(Plate 4-2)

These spores are quite similar to those produced
by the living 2. vulgare and are the only ones within the
family that can be assigned to a genus with some degree
of certainty. The spores are monolete and reniform, rang-
ing in size from 35 by 45 to 50 by 70 micrometers. The
single scar is 30 to 40 micrometers in length and the
surface of the spore is characteristically rugulate.
Spores of this type were previously described from the
flora by Graham (1965). They are very common in some beds
at the middle of the Valley section and comparatively
rare elsewhere.

Location: Pb-9268-3 V-3.7xH10.6

Polypodiaceae Spores of Uncertain Generic Affinity
izei
(Plate 4-7)
These small reniform monolete spores average 17 by
26 micrometers in size. They represent the smooth endo-
spore which remains after the sculptured exospore has
been shed. Because of their generalized features they can-
Iubt be assigned to any particular genus. Spores of this
typeeoccur in small numbers throughout the study sections.

Location: Pb-9157-l V-8.le12.5

ire;
(Plate 4-1)

These spores are uniformly larger than those of
Type 1, averaging 30 by 45 micrometers in size. They are
monolete with the smooth reniform shape characteristic
of endospores within the Polypodiaceae, but cannot
reliably be assigned to any particular genus because of
their generalized morphological features. Graham (1965)

identified spores of this type as Woodwardia on the basis

 

of the occurrence of Woodwardia fronds in the macroflora.

 

Although such occurrences are useful in indicating possi-
ble affinities of the spores, the use of such a procedure
in identifying the dispersed spores is completely

inadmissable. There is at present no unequivocable evi-

dence for the presence of Woodwardia in the microflora

 

although it is likely that some of the spores of this
type may have been produced by the genus. Spores of this
type are found in small numbers throughout the study sec-
tions, particularly in the organic facies.

Location: Pb-9157-l V—8.7xH12.6

VASCULAR PLANT SPORES OF UNCERTAIN
SYSTEMATIC POSITION

Monolete

 

Type i
(Plate 4-4)

The spores of this type are reniform, ranging in

Size from 25 by 42 to 30 by 50 micrometers. The surface

104

is densely fimbriate but it has not been possible to
determine if this is the original condition of the spores
or whether it is the result of differential decay or the
accumulation of organic debris. The spores occur in
small numbers in the Valley and lower Shortcut and Rock-

ville sections.

Location: Pb-9308-3 V+7.4xH14.6

ire;
(Plate 4~5)
Only a single specimen of this type was noted in the
study. It is ovate, 34 by 44 micrometers in size and

has a single scar which is visible on the upper surface

in the illustration. The surface is verrucate. The
spore was recovered from the organic beds near the center

of the Valley section.

Location: Pb—9324-3 V+9.7lel.l

Trilete
Eras}.
(Plate 4-10)

The spores of this type are sub-triangular, meas-
uring approximately 36 micrometers from an apex to the
center of the opposite side. The surface is coarsely
granulate and the trilete scar is bordered by a thickened
ridge with a rugulate texture. It was not possible to

relate this type to any particular modern group. A small

105

number of specimens were observed in preparation from
the organic beds at the middle of the Valley section.

Location: Pb-9158—7 V+l3.5xH16.l

2222?.
(Plate 4-6)

Only a single specimen, recovered from the base of
the Rockville section, was noted in the course of the
study. It measures approximately 26 micrometers in dia—
meter and has a smooth surface somewhat pitted by differ-
ential corrosion.

Location: Pb-9182-l V+7.9lel.6

Class GYMNOSPERMAE
Family PINACEAE
Genus ABIES L.

(Plate 5)

Two types of Abieg pollen were observed during
the study. Pollen of the genus is characterized by large
size, a pronounced resentrant angle between the bladders
and cap, and a sharp transition in sculpturing between
the cap and bladders. Graham (1965) considered Abigs
pollen to be relatively rare in the Sucker Creek micro-
flora but this is definitely not the case. Abigs pollen
is confined to the Valley and lower Shortcut and Rockville
sections but where it is present it often reaches levels
of 10 percent of the total number of pollen grains and
spores. The pollen grains of Agigg are quite large and

heavy and representation at a level of up to 10 percent

106

would indicate that fir stands were often present near

the depositional basin.

reel
(Plate 5-1)

This is the most common type accounting for over
95 percent of the fir pollen counted during the quanti—
tative phase of the study. The cap is thick and measures
between 120 and 140 micrometers across. The bladders are
attached with a pronounced re-entrant angle and measure
between 85 and 100 micrometers in diameter. The cap is
rugulate while the bladders have a reticulate pattern
superimposed on a rugulate surface texture. This type
appears identical to the form described by Graham (1965).
The various modern equivalents of the various fir species
described from the Miocene of the Columbia Plateau inter—
grade to such a degree in their pollen morphology that it
is not possible to make a specific determination on the
basis of the fossil pollen.

Location: Pb-9157-1 V+9.4XH17.5

ire—22.
(Plate 5—2)

This pollen type is comparatively rare and appears
to be confined to the Valley section. The cap is quite
thick and measures approximately 90 micrometers across
with a finely rugulate surface texture. The bladders are

coarsely reticulate and measure 58 to 65 micrometers in

107

diameter. Grains of this type have not previously been
described from the flora and it has not been possible to
relate the pollen to any modern species.

Location: Pb-9158-l V-5.2XH16.0

Genus PICEA L.
(Plate 6)

Pollen of spruce is one of the most significant
components of the microflora and is dominant at many
levels in the Valley and lower Shortcut and Rockville
sections. The pollen occurs in two forms which can
usually be readily differentiated unless the orientation

of the grain is extremely poor.

2x221
(Plate 6—1)

This grain is the larger of the two types and is
generally the most common. The grains commonly measure
between 100 and 130 micrometers across the cap with the
entire grain measuring 130 to 150 micrometers in length.
Both the cap and bladders are rugulate. Although not
figured, this is undoubtedly the larger of the two types
discussed by Graham (1965) in his treatment of the spruce
pollen of the microflora. Grains of this type are quite
similar morphologically to those of the living P.
likiangensis.

Location: Pb-9157-l V+10.2xH19.l

2292.2.
(Plate 6-2)
This pollen type is typical of that illustrated by
Graham (1965) and is quite similar to that of the living

3. engelmanni. The bladders are commonly folded quite

 

close to the body of the grain, the latter measuring from
96 to 120 micrometers in length. The cap and bladders
range from verrucate to rugulate in surface texture.

Location: Pb-9158-7 V+18.0xH5.3

Genus PINUS L.
Pine pollen is a major constituent of the pollen
spectra at all levels in all sections. Five morphological

types (1, 2, 4, 5, 6) are recognized in the present study.

Type i
(Plate 7-2)

The bodies of the grains measure 45 to 55 micro-

meters across and have a finely rugulate surface texture.

\b—J:

The bladders are finely reticulate and usually somewhat
flattened. This appears to be the same type as illus-
trated by Graham (1965). It strongly resembles the

pollen of P. strobus and g. monticola, both of which are

 

similar in their vegetative morphology to g. wheeleri, a
widely distributed species in the Miocene of western
North America. This type reaches its greatest numbers
in the Valley and lower Shortcut and Rockville sections,

but may be found in the upper part of the latter two sections

109

in somewhat reduced numbers. P. baileyana, a pollen type

 

described by Traverse (1955) from the Brandon lignite of
Vermont (Oligocene?), is almost identical to this pollen
type.

Location: Pb-9169-3 V+20.lell.4

"£11222
(Plate 7-6)

Pollen of this type appears confined to the lower
part of the Valley section. The cap averages approxi-
mately 35 micrometers long and is quite thick for its
size. The bladders vary from 25 to 34 micrometers in
diameter and are often somewhat flattened with an auri-
culate margin where they are folded against the body of
the grain. Pollen of this type has not previously been
described from the flora and it has not been possible to
relate it to a species within the genus although the
grains resemble those of g. remorata of the western United
States.

Location: Pb-9157-l V+6.2xH14.6

was.
(Plate 7-4)

Grains of this type range in size from 30 to 40
micrometers across the cap with the bladders averaging
approximately 25 micrometers in diameter. The bladders
are coarsely reticulate and the body ranges from granular

to finely verrucate. This pollen type has not previously

110

been described from the flora and its affinities within
the genus are not known. It is a comparatively rare
pollen type which is distributed throughout the study
sections.

Location: Pb-9157-6 V+l.le7;9

we:
(Plate 7-5)

This pollen type closely resembles the pollen of
the living 2. muricata and is characterized by a shallow
re-entrant angle at the point of attachment of the bladders
and cap. The body measures 50 to 60 micrometers in length
with its texture ranging from verrucate to rugulate. The
bladders are coarsely reticulate and average approximately
30 micrometers in diameter. This pollen type has not
previously been described from the flora. Morphologically

it is identical to P. pristipollinia, a pollen type des-

 

cribed by Traverse (1955) from the Brandon lignite of
Vermont. It is found in the upper half of the Rockville
and Shortcut sections.

Location: Pb-9191-3 V-5.2XH13.0

2x229.
(Plate 7-3)
This pollen type has a body ranging from 45 to 55
micrometers in length with bladders averaging 33 micro-
meters in diameter. There is a sharp re-entrant angle at

the point of attachment of the bladders and cap. The body

111

is granular to finely rugulate and the bladders are
coarsely reticulate. This pollen type is a new addition
to the flora and strongly resembles the pollen of the

extant g. contorta. It is found in the upper half of the

 

Rockville and Shortcut sections.

Location: Pb-9l9l-3 V+6.3lel.5

Genus TSUGA L.
(Plate 7-1)

The hemlock pollen observed during the study is
spherical, ranging from 70 to slightly over 100 micro-
meters in diameter. The surface is convoluted and one
side of the grain tends to be collapsed due to a thinning
of the exine in that area. The exine often becomes some-
what separated from the body of the grain giving it the
appearance of being surrounded by a sac-like bladder.
This pollen type was first described from the flora by
Graham (1965) who considered it to resemble the pollen of

T, heterophyila, an extant species growing in western

 

North America. Pollen of this type is confined to the
Valley and lower Shortcut and Rockville sections. It may
reach relative percentages as high as 5 percent but values

of 1-2 percent are more common.

Location: Pb-9158-1 V-6.1le6.8

112

Family PODOCARPACEAE
Genus PODOCARPUS L'Herit. ex Pers.
(Plate 7-8)

Pollen of this genus is a new record for the flora and
may represent the youngest known record of the genus in the
Tertiary of North America. The cap ranges from 30 to 40
micrometers across and is deeply convoluted, characteris-
tically staining very deeply. The bladders are large in
relation to the body of the grain and are coarsely reticu-
late. The length of intact grains varies from 68 to 82
micrometers. The grains are apparently confined to the
Valley section where they occur at levels of 1-2 per 1000
in the organic sediments in the middle of the section.

Podocarpps has long been considered to have had only a

 

Mesozoic distribution in North America but recent studies
indicate that it may have had a distinct if somewhat
limited role in various Tertiary floras. The first
authenticated occurrence of Tertiary leaf material was
reported by Dilcher (1969), who was able to recover

Podocarpus cuticular material from the Eocene deposits of

 

Puryear, Tennessee. This find, coupled with occurrences

of pollen of the genus in Tertiary deposits (Sparks, 1967
and Leopold, 1969) would appear to indicate that the genus
was present and somewhat widespread in early Tertiary

time in North America. The presence of pollen of the

genus in the Miocene Sucker Creek flora probably represents

the latest record of the genus in North America. Although

113

it cannot be demonstrated with certainty, the overall
patterns of derivation of plants from temperate Tertiary
floras in western North America would favor the hypothe-
sis that the source plants for the pollen were probably
derived from temperate Asian forms rather than sub-tropi-

cal or southern hemisphere species. 2. macrophylla of

 

Japan and g. neriifolia of mainland China are two species

 

which appear likely as possible analogues of the Sucker

Creek source plants. g. neriifolia is widely distributed

 

from the Himalyas to southwestern China (Lee, 1935),

while P. macrophylla is to be found in warm-to moderate

 

temperate areas in Japan. It is possible that Podocarpus

 

occupied habitats of a somewhat sheltered nature and was
probably to be found in small numbers in the more mesic
lowlands rather than the more rigorous sites on the higher
slopes. The trees may have persisted in the areas as
relicts, only to be eliminated during the drying interval
indicated during the latter part of the Rockville -
Shortcut sequence.

Location: Pb-9157-3 V-4.6xH7.l

Family TAXODIACEAE

(Plate 7—7)

Identification of pollen assigned to the Taxodiaceae

(TCT) cannot be accomplished at the generic level with any

degree of reliability using the light microscope. Criteria

for distinguishing individual genera (see Traverse, 1955)

will partition out the various morphological types present

114

in the flora but these various types have no consistent
relationship to the identity of the source plants.
Taggart (1967) applied the criteria outlined by Traverse

(1955) to the range of variability presented by Taxodium

 

pollen preserved in modern sediments in southern Illinois
cypress swamps. Based on their morphology: it was possible
to recognize the presence morphological analogues of Taxodium,

Glyptostrobus, Metasegpoia, and Seguoia. Since TaXodium was

 

 

 

in actuality the only source plant, it was felt that the
mOrphological criteria resulting in such incorrect deter-
minations should be rejected. On the basis of plants

known to have been growing in the Columbia Plateau region

during Miocene time, two genera, Taxodium and Glyptostrobus

 

emerge as the two likely possibilities for the Sucker Creek

source plants. Glyptostrobus is found in the macroflora

 

while Taxodium, although widely distributed in floras of

 

similar age, is not. On this basis alone, it is highly
likely that a great deal of the taxodiaceous pollen is

derived from Glyptostrobus. In addition, the peak in TCT

 

pollen in the Valley section corresponds to a peak in the

occurrence of Glyptostrobus macrofossils. At least some

 

of the fossil wood in the upper Rockville organic beds is
assignable to the Taxodiaceae and provisionally has been

placed in the genus Glyptostrobus. Although it must be

 

admitted that Taxodium or even other genera in the family

 

may have grown in the area without being represented in

the macroflora, it appears probable that much of the TCT

115

pollen in the Sucker Creek sediments was derived from

Glyptostrobus. It must be emphasized however that this

 

conclusion is inferential and is in no way based on the
morphology of the fossil pollen grains.

The grains themselves are typically 25 to 32
micrometers in diameter and may assume a variety of forms,
all of which are ultimately derived from an original
spherical form. The specimen illustrated shows a gaping
ruptured sphere with a small germinal papilla, typically

assigned to the form species Taxodiaceaepollenites hiatus

 

(Pot.) Kremp. Another form, often referred to the genus
Sequoia or its "form" equivalents, consists of unruptured
grains with a somewhat longer papilla. Another common
configuration consists of collapsed and folded grains,

often referred to as Glyptostrobus. The form illustrated

 

is the most common, but a complete series of gradational
forms may be found reinforcing the authors opinion that
no valid distinctions within the family may be made on
the basis of pollen morphology observed with the light
microscope.

Location: Pb-9158-l V+4.lel7.3

Class ANGIOSPERMAE
Sub-class MONOCOTYLEDONAE
Family GRAMINEAE
Grass-like pollen is a common constituent of the

microflora but the generalized morphological features of

116

the pollen grains do not permit them to be identified with
any precision below the level of family. Pollen of the
family typically has a thin hyaline exine with a single
pore. (The latter is often surrounded by thickened
annulus. In the fossil material the pore is rarely observed
due to the ease with which the grains are collapsed and
torn. Tearing commonly involves the pore structure and

it is not possible to demonstrate its presence in all

cases .

Eras}.
(Plate 9-2)

This is the most common type encountered, compris-
ing over 90 percent of the grains assigned to the family.
The hyaline exine is typically folded and torn. The
grains range in size from 30 to 50 micrometers. Due to
the distorted nature of most of the material it is possi-
ble that some grains belonging to the Cyperaceae may have
been tallied in this group.

Location: Pb-9157-l V+8.6le4.0

nee;
(Plate 9-3)

In this form the pore is commonly preserved, prob—
ably due to the thicker and somewhat more resistant exine.
In the specimen figured the pore is visible in optical
section at the top of the pollen grain. The grains are

somewhat ovate measuring 25 to 35 by 35 to 45 micrometers.

117

The pore is approximately 4 micrometers in diameter.
This form is not common and is confined to the upper
Shortcut and Rockville sections.

Location: Pb-9230-1 V-5.8XH9.3

$222.3.
(Plate 9—4)

This form is somewhat smaller than the previous
types ranging from 22 to 28 micrometers in diameter. The
pore is usually visible and the grains are rarely collapsed,
probably due in part to their smaller size. This type is
rare and only a small number of grains were observed in
the upper Rockville section.

Location: Pb-9l9l-3 V-5.9xH27.4

Family POTAMOGETONACEAE
Genus POTAMOGETON L.
(Plate 10-5)

Pollen of this genus was first described from the
flora by Graham (1965). The grains are spherical,
inaperturate, and have a well-developed reticulum. They
range in size from 30 to 35 micrometers. It is not
possible to relate the fossil material to any extant species
due to the generalized nature of the pollen within the
genus. It is found in the upper Valley and lower Shortcut
and Rockville sections and is one of the types used as an
indicator of open water habitats.

Location: Pb-9158-l V-2.7le7.0

118

Family TYPHACEAE
Genus TYPHA L.
(Plate 10—10)

These grains are typically spherical with a single
aperture. The borders of the pore are somewhat diffuse
and the grain has a reticulate exine structure. The
grains range from 25 to 30 micrometers in diameter.

Pollen of this type was previously described by Graham
(1965). It appears to be most closely allied to T.

angustifolia, based on the fact that the grains are shed

 

singly rather than in rhombohedral tetrads. Grains of
the latter type are characteristic of T. latifolia. The
pollen is found at intervals throughout all of the study

sections but the grains are never very common.

Location: Pb—9158-1 V-2.0lel.8

Sub-class DICOTYLEDONAE
Family ACERACEAE
Genus ACER L.

Maple pollen is relatively common in the macro-
flora and two general types are recognized. There are
undoubtedly more than two taxa represented, but separation
<of even modern material at the species level is extremely
<iifficult. There are six species of maple recognized
frtnn the Miocene of the Columbia Plateau and all of them
«occur'in the macroflora (Graham, 1965). Future study may

seznna to partition the maple pollen complex into groups

119

that more closely approximate individual species or

groups of species.

The}.
(Plate 8-1)

These grains are tricolpate with the colpi reach-
ing almost to the poles. The grains are prolate and
measure approximately 25 by 35 micrometers. The exine
has a clear striate pattern which makes this type easy to
recognize. Graham (1965) illustrates pollen of this type
and cites its similarity to that of A. negundo. Grains
of this type are found throughout the study sections but
are most numerous in the Valley and lower Shortcut and
Rockville sections prior to the floristic transition.

Box elders were probably members of the floodplain commun-
ity and persisted in this role after the majority of the
mesic forest trees had disappeared from the area.

Location: Pb-9158-7 V+l7.le10.7

221222.
(Plate 8-2)

Except for its larger size and somewhat more
gaping colpi when viewed in polar View, the overall char-
acteristics of this type are similar to Type 1. The
grains range in size from 37 to 42 by 49 to 61 micrometers.
The character of the striae suggest that this type may be

allied to the g. saccharum - A. grandidentatum_group. This

 

 

type is confined to the lower part of the composite section

120

and was first described by Graham (1965). It is interest-
ing to note that the overall peak in Agg£_pollen, com-
posed primarily of Type 2, occurs in the fossiliferous
shale of the upper Valley section where very fine maple
leaves have been collected.

LocatiOn: Pb-9268-3 V+O.le7.7

Family AQUIFOLIACEAE
Genus ILEX L.
The fossil record of £l§§.in the Miocene of the
Columbia Plateau is very limited. Only one species,

Ilex fulva, occurs in the macroflora and it is quite

 

rare. Holly pollen has not previously been recognized
in the flora but two types were noted in the present
study. Both types are limited in occurrence being con-
fined to the organic sediments near the middle of the
Valley section. It is possible that the source plants
for both types were associated with the development of
the swamps which appear to have been present at that

time.

2222.1.
(Plate 9-5)
The grains range in size from 19 to 22 by 31 to 37
micrometers. The surface is densely covered by clavae
up to 2.5 micrometers in length. The grains are tricolpate

with the furrows constricted at their midpoint. This

121

constriction is often obscured by the dense sculpturing
of the exine.

Location: Pb-9157-l V-7.8xH32.9

3223
(Plate 9-6)

The grains of this type are of the same general
size as those of Type 1 but the clavae are uniformly
smaller, averaging approximately 1 micrometer in length.
The furrows also have very little constriction at their
centers.

Location: Pb—9264-1 V+7.6xH16.5

The two pollen types described are quite distinct
and no gradational forms were noted in any of the grains
examined. Traverse (1955) describes several iigg "species"
in the Brandon lignite pollen flora but the Sucker Creek
material does not resemble any of them. On the basis of
the pollen data it would appear that at least two species
of holly grew in the Valley area during Sucker Creek time
but they were probably not common. The lack of a complete
suite of reference material made it impossible to relate

the fossil material to any modern species.

Family BERBERIDACEAE
Genus MAHONIA Nutt.
(Plate lO—l)
Three species of Mahonia are presently recognized

in the macroflora (Graham, 1965), two of which are allied

122

to species now growing in eastern Asia and one of which
is presently found in western North America. The Mahonia
pollen found during the present study is a new record for
the flora. The grains are tricolpate and spheroidal,
ranging from 35 to 43 micrometers in diameter. The sur-
face ranges from coarsely granular to finely verrucate.
The furrows usually gape giving the grains the appear-
ance of an incised sphere. The fossil material

closely matches pollen of M. aquifolium in the

 

Michigan State reference collection, but there was not
enough material available from other species to fully
evaluate the status of the fossil material. Although
Mahonia leaves are well represented in fossil deposits

of late Tertiary age from western North America, this

is the first record, to the author's knowledge, of pollen
of the genus. Pollen of this type occurs in most samples
from the Valley and lower Rockville and Shortcut sections
but is rare or absent in the upper parts of the latter
two sections.

Location: Pb-9158-1 V+4.2xH5.9

Family BUXACEAE
Genus PACHYSANDRA Michx.
(Plate 10-8)
The first clear report of the occurrence of

Pachysandra pollen in the Tertiary of western North America

 

was made by Gray and Sohma (1964). Pollen of the same

123

general type has been referred to as Erdtmanopollis spp.
or Multiporopollenites ludlowensis in the stratigraphic
palynological literature but the affinities of these

pollen types with Pachysandra is clearly indicated in

 

Gray and Sohma's paper. This is the first record of pollen
of this type in the Sucker Creek flora although it has

been reported from a wide variety of late Miocene floras

in the Columbia Plateau and adjacent regions (Gray and
Sohma, 1964). The pollen from the Sucker Creek sediments
is spherical, measuring approximately 50 micrometers in
diameter, and multiporate. Each of the pores is surrounded
by a "circlet" of wedge-shaped and rectangular sculpture
elements. Of the various types illustrated by Gray and
Sohma (1964) those from Moose Creek,Idaho appear closest
to the Sucker Creek material. The grains are found in
small numbers in the lower and middle Valley section in
highly organic sediments. Due to the large size and heavy
nature of the pollen and the low sprawling habit of the
source plants that would not facilitate ready dispersal

of the pollen grains, it is unlikely that the plants

grew at any distance from the basin.

Location: Pb-9324-l V+O.4XH22.3

124

Family CAPRIFOLIACEAE
(Plate 10-6)

Two specimens referable to the family were noted
during the present study. They average 15 by 20 micro-
meters in size and have a well developed reticulate sur-
face pattern. The grains are tricolporate and appear to
have small inward projections on the pore rims. The

specimens appear identical to Caprifoliipites viridi-

 

fluminis described by Wodehouse from the Eocene Green River

 

formation (1933). As noted by Wodehouse, except for its

small size, pollen of this type is identical to Viburnum.

 

Pollen of this type has not previously been described
from the flora although the family is represented by a

- single specimen of gymphoricarpos salmonensis from the

 

macroflora. The pollen grains were recovered from the
organic sequence in the middle of the Valley section.

Location: Pb-9324-2 V-3.3leO.9

Family CHENOPODIACEAE
Genus SARCOBATUS Nees.
(Plate 8-9)

Pollen grains of the Chenopodiaceae and Amaranthaceae
are usually difficult to separate from one another due to
the similarity of their morphological features and are
usually lumped into a single category labeled "Cheno—Am."
Certain members of the family are distinctive enough to

perndt.recognition and pollen of Sarcobatus is one of these.

 

The pollen grains are multiporate and spherical, ranging

125

from approximately 20 to 28 micrometers in diameter. The
exine is granular and each pore is set in a somewhat
depressed field giving the grains the appearance of

polyhedra rather than spheres. Sarcobatus has not pre—

 

viously been recognized in the microflora but it has been
described from a number of other late Tertiary floras
including the Creede flora (late Oligocene) of Colorado
and the Troublesome Formation (Middle Miocene) of north-
central Colorado (Leopold, 1969). The pollen grains may
be noted from samples at all levels in the study sections
but reach their greatest abundance in the upper Rockville
and Shortcut sections.

Location: Pb-9lS8-7 V+8.5le9.7

Chenopodiaceae of Uncertain Generic Affinity
22.22;
(Plate 8-8)

As stated previously, pollen of the Chenopodiaceae
is often difficult to distinguish from that of the
Amaranthaceae. Grains of this type might well belong to
either family. The grains are spherical, averaging 30
micrometers in diameter, and multiporate with a distinctive
granular appearance. Graham (1965) illustrated pollen of

this type and noted its resemblance to pollen of Atriplex,

 

Chenopodium, and Amaranthus. The form can be found in

 

the lower part of the composite section but reaches its

126

greatest variability in the upper Shortcut and Rockville
sections.

Location: Pb-9324—l V+0.4lel.8

Family COMPOSITAE
Genus ARTEMISIA L.

Pollen of this genus occurs in two distinct sizes
which, coupled with morphological differences, would tend
to indicate that at least two taxa are involved. The
grains are tricolporate but the pores are difficult to
observe due to the tendency of the grains to orient pre-
ferentially in polar View. The grains lack visible spines,
the furrows are deep and prominant, and a columellate

tectum is well-developed in the interporate regions.

we;
(Plate 8-10)
These grains average 23 micrometers in diameter
with an interporate wall thickness of approximately 4
micrometers of which the columellae and other ectexine
elements comprise approximately half this thickness.

Location: Pb-9l9l-3 V+2.9XH22.6

Type 2
(Plate 8-11)

This form is approximately 20 micrometers in dia-

Ineter and the wall in the interporate region is

127

approximately 4.5 micrometers thick with the ectexine
comprising approximately two-thirds of this thickness.
Location: Pb-9182—l V+121.0xH33.0
Although the two types are similar in some features,
the size variation and the differences in wall structure
in the interporate region justifies the recognition of
two distinct types. The larger of the two, Type 1, is

indistinguishable from A. tridentata, the dominant species

 

in the Sucker Creek area today.

Compositae Pollen of Uncertain Generic Affinity
11122.1.
(Plate 8-14)

This type appears identical to the grains described
by Graham (1965) as "Unknown Composite Pollen." This is
the only Compositae type which is consistantly present in
the mesic forest zone of the composite section. The grains
are comparatively rare in the lower part of the section
and unlike other members of the family their frequency
does not increase toward the top of the section. The grains
are tricolporate and approximately 20 micrometers in dia-
meter. The spines are broad at their bases and compara-
tively short, rarely exceeding 1 micrometer in length.

Location: Pb-9158-6 V0.0leO.7

322.2.
(Plate 8-15)
Grains of this type are tricolporate and spinose.

The grains average approximately 25 micrometers in diameter
and the spines are short, averaging approximately 1 micro-
meter in length. The exine is granular and appears to
break into a polygonal pattern in L—O analysis. Pollen of
this type has not previously been described from the flora.
Only two grains were encountered in the study, both of which
were found in the upper Rockville section.

Location: Pb-9197-1 V+3.2XH20.0

m3.
(Plate 8-16)

These tricolporate pollen grains average 25 to 30
micrometers in diameter with spines approximately 2
micrometers in height. The base of the spines have a dia-
meter approximately equal to their height. This pollen
type is a new addition to the flora and it is relatively
common in the upper Rockville and Shortcut sections.

Location: Pb-9l96—1 V+l.7xH8.4

2x222
(Plate 8-17)
These tricolporate pollen grains average 18 to 22
1micrometers in diameter with spines which are approximately

3 Inicrometer in length. The base of the spines range from

2-12.5 micrometers in diameter. These grains have not

129

previously been described from the flora and are found in
the upper Shortcut and Rockville sections.

Location: Pb-9l95-l V+3.3xH25.l

1mg
(Plate 8-12)

Grains of this type are tricolporate, ranging from
22 to 27 micrometers in diameter. The Spines are compara-
tively long averaging approximately 6 micrometers in
length and 2.5 to 3 micrometers in diameter at their
bases. This type has not previously been described from
the flora and appears limited to the Upper Rockville and
Shortcut sections.

Location: Pb-9246-l V-0.9xH26.3

221.229
(Plate 8-13)

These are the largest composite grains encountered
in the study, ranging from 30 to 35 micrometers in dia-
meter. The grains are tricolporate with spines measuring
3 micrometers in length and 2.5-3 micrometers in diameter
at the base. Pollen of this type is a new addition to the
flora.

Location: Pb-9l97-l V+2.6xH22.2

The greatest number and variety of Compositae
pollen are found in the upper Rockville and Shortcut sec-
tions. Due to the generally poor preservation characteris-

tic of these beds, coupled with the large number of species

130

in the family, identification of the pollen types to

genus must await further study.

Fami ly CORYLACEAE
Genus ALNUS Mill.
(Plate 8-3)

Alder pollen from the Sucker Creek study sections
ranges in form from tetraporate through hexaporate with
the pentaporate condition being the most common. The pores
are equatorially arranged with each pore surrounded by
annular thickening giving the pores a protruberant appear-
ance. Sub-exinous thickenings, arranged in arcs between
the pores give the grains a characteristic appearance in
(transmitted light. The exine is smooth and the grains
range from 22 to 30 micrometers in diameter. Graham
(1965) describes pollen of this type and his figures on
the distribution of pore numbers appears to correspond
with the observations made during the present study.
Graham concluded that pore number was not a useful charac-
ter in delimiting taxa within the genus and the author
concurs. Alder is widely distributed in middle and late
Tertiary floras both in the form of leaves and pollen, but
only a few leaves have been collected from the Sucker Creek
sediments. Alder pollen dominates the record at some
levels and then drops to moderate or low numbers at other
points on the study sections. It is possible that alders

were associated with a restricted community type and that

131

they were not widespread in the deciduous forest complex.

A likely hypothesis is that the shrubs or small trees

grew in swampy situations closely associated with the

sites of organic sedimentation. The latter may be inferred
on the basis of the fact that clumps of large numbers of

the grains may be observed in some of the lignitic sedi-
ments suggesting that whole catkins dropped into the swamp.
These organic sediments do not contain well—preserved fossil

leaves and this probably accounts for its poor representation

in the macrofossil record. Alder pollen is reasonably
common in all productive samples from the lower part of
the composite section but persists into the upper xeric
zone in much reduced numbers.

Location: Pb-9158-6 V+5.0le0.0

Genus BETULA L.
(Plate 8—4)

These pollen grains are triporate with a sub-rounded
outline and average 25 micrometers. The pores are aspidate
due to the presence of annular thickenings. The exine is
smooth and the fact that the grains have few outstanding
features makes it impossible to relate it to any particular
modern species or species group. Graham (1965) was the
first to describe the occurrence of birch pollen in the
Sucker Creek flora. There is no way to determine how many
species might be represented in the fossil material.

Graham's total for birch pollen grains (560) is larger than

132

that which he found for alder (485) giving the impression that

birch is somewhat more common, but this is not the case.
Birch and alder usually occur in the same samples but the
latter exceeds birch in almost all cases. The relative
numbers of the two genera as determined by Graham would
appear to indicate that none of his samples represent
levels comparable to the alder maxima observable in the
three study sections. Birch pollen is confined to the
lower part of the composite sequence occurring only in
the Valley and the lower Shortcut and Rockville sections.

Location: Pb-9l65-20 V+l4.4le6.6

Genus CARPINUS L.
(Plate 8-6)

Grains of this type range in diameter from 20 to
25 micrometers with a somewhat rounded triangular outline.
The grains are triporate with the pores arranged around
the equator. The pores are annulate but protrude to far
less a degree than those of Alnus or Betula. The exine
ranges from psilate to faintly granular. Graham (1965)
describes pollen of this type and remarks that it is diffi-

cult to distinguish pollen of Carpinus and Ostrya. Since

 

Ostrya is the only genus of the two represented in the
macroflora, Graham was of the opinion that the Sucker

Creek pollen material represented that genus. Although

the two genera are somewhat similar, Wodehouse (1935) noted

that Ostrya pollen differed from that of Carpinus in two

 

characters: Ostrya has up to 25 percent of the grains with

2”. ml"- flfirm .h \l

133

four pores while Carpinus grains have only three pores,

 

and the pores of Ostrya are elliptical, often twice as

long as broad, while those of Carpinus are circular. All

 

of the Sucker Creek pollen grains had three pores and the
pores were uniformly circular, both in the material
observed in the present study and the material described
by Graham. All of these characters correspond to Carpinus
and it is on this basis that the material is so assigned.
The pollen is restricted to the mesic forest zone in the
lower part of the composite section.

Location: Pb-9207-l V+6.le25.2

Family ELAEAGNACEAE
Genus ELAEAGNUS L.
(Plate 8-20)
The pollen grains are sub-circular to sub-triangular

with three short colpi. The grains range in size from 23
to 28 micrometers in diameter. The exine is granular and
pores are present in the equatorial region of the furrows
but are quite inconspicuous. The exine is thickened in
the area of the colpi giving the grains their angular
appearance. The grains are very similar to those of E.
pungens in the Michigan State reference collection but
insufficient material was available for detailed comparison
with other species. The genus includes shrubs which are
widely distributed in the temperate areas of Europe, Asia,
and North America. Lee (1935) lists 24 species, most of

which grow at altitudes ranging from 500 to 6000 feet in

134

Szechuan and Hupeh provinces in China. Pollen of the
genus has not previously been described from the flora but
it has been noted in deposits of Oligo-Miocene age from
Alaska (Leopold, 1969). Pollen grains of this type have
been noted in the Valley and lower Rockville sections.

Location: Pb-9219-l V+7.7le7.4

Genus SHEPHERDIA Nutt.
(Plate 8-19)
The presence of this genus in the flora was first
documented from the flora by Graham (1965), who described

the material as Shepherdia argenteaites based on its

 

resemblance to the pollen of the extant S. argentea, pre-
sently found in the northern United States and Canada.
According to Graham (1965), the species is found in sage-
brush and pinyon-juniper woodlands in western North America
ranging in altitude from 3500 to 6500 feet. Jepson (1960)
indicates that the species is often closely associated with
watercourses where it occurs in California. The grains are
tricolporate, ranging from 20 to 30 micrometers in dia—
meter, and have a pronounced triangular outline. The exine
is granular. The colpi are quite long, extending almost

to the poles, a feature which distinguishes Shepherdia

 

pollen from Elaeagnus where the colpi are quite short. This

 

type is confined to the mesic forest zone.

Location: Pb-9218-1 V-4.1xH22.2

135

Family ERICACEAE
(Plate 8-18, 21)

Pollen grains in this family are commonly shed as
tetrahedral tetrads. The individual grains are tricol-
porate but the colpi are shared by adjacent grains making
the structure of the furrows and pores somewhat obscure
in the fossil material. The individual grains have a
psilate surface texture and the tetrads vary in size from
30 to 40 micrometers in diameter, somewhat smaller than
the tetrads described by Graham (1965). The size of the
tetrads in the present study is similar to those described
by Traverse (1955) and there may be several taxa involved.
Arbutus has previously been described from the macroflora

and leaves of Vaccinium were collected in the course of

 

the present study so that at least two ericaceous genera
are known to be represented. Tetrads in the order of 30
to 40 micrometers are consistant in size with those of

Vaccinium but it is possible that other genera may have

 

been the source plants. It would appear that at least two

taxa are represented in the microflora, those illustrated

here and the somewhat larger tetrads described by Graham

(1965). All of the ericaceous pollen observed in the

present study was confined to the mesic forest zone of

the Valley and lower Shortcut and Rockville sections.
Location: #18 Pb-9308-3 V+5.3le4.2

#21 Pb-9246—l V+1.9XH23.0

136

Family FAGACEAE
Genus CASTANEA Mill.
(Plate 8—5)

Pollen of this genus has not previously been des-
cribed from the flora although its leaves have been found
(Graham, 1965). The grains are tricolporate and quite
small, averaging 9 by 16 micrometers in size. The furrows
extend almost from pole to pole and a transverse furrow
is evident in the equatorial region of each longitudinal
furrow. The exine is psilate. The grains correspond in
all respects to pollen described by Traverse (1955) from the
Brandon lignite and which he described as Q. insleyana.
Except for a single occurrence in a lignitic bed in the
upper Rockville section, the pollen of this genus is con—
fined to the Valley and lower Shortcut and Rockville sec-

tions. Castanea was probably a member of the mesic

 

bottomland forest but the small number of leaves and the
paucity of the pollen record indicates that the trees were
probably not common.

Location: Pb-9157—2 V+8.4xH26.1

Genus FAGUS L.
(Plate 9-1)
The grains range from ovate to sub-spheroidal and
are tricolporate with the furrows extending almost to the
poles. The grains range from 30 by 40 to 40 micrometers

in diameter depending upon their shape. The surface is

137

coarsely granular. Graham (1965), who first described the
occurrence of pollen of this type in the flora, noted that

the material closely resembles the pollen of E. grandifolia.

 

The single species known from the macroflora (E.

 

washoensis) is morphologically similar to E. grandifolia

 

and it is therefore likely that the pollen was derived

from trees of the E. washoensis type.

 

Location: Pb-9158-1 V-6.8xH7.0

Genus QUERCUS L.
(Plate 10-11, 13)

The oaks of the Sucker Creek macroflora are a
heterogenous assemblage of approximately six species of
varying taxonomic and ecological affinities (Graham, 1965).
Graham noted the presence of two forms of oak pollen, a
small form approximately 18 by 30 micrometers and a larger
form up to 32 by 42 micrometers. The grains are tricol-
pate with the smaller forms tending to tricolporate. Exine
surface structure ranges from psilate to granular. The
results of the present study indicate that the size dis-
tinction breaks down when a large number of grains are
examined and that the oak pollen complex is an intergrading
series in which it is not possible to relate individual
members to distinct modern taxa. It is probable that all

of the macrofossil species contributed to the pollen record

138

and it is possible that additional species, growing
farther from the basins, may be represented as well.
Location: #11 Pb-9157-l V+9.3xH14.6

#13 Pb-9157-1 V+9.9XH10.0

Family HAMAMELIDACEAE
Genus LIQUIDAMBAR L.
(Plate 9-8)

The grains of this type are spherical and multi-
porate. The pores are evenly distributed over the surface
of the grains and each pore has a conspicuously flecked
membrane. The exine is granular and the diameter of the
grains ranges from 32 to 40 micrometers. Pollen of this
genus was originally described by Graham (1965) from the
Sucker Creek sediments. It is fairly common in the
mesic forest zone at the bottom of the composite section.

Location: Pb-9158-7 V+18.7xH22.0

Family JUGLANDACEAE
Genus CARYA Nutt.
(Plate 8-7)
The grains are triporate and sub-triangular or

rounded in polar View with a diameter of approximately 45
micrometers. The pores tend to be somewhat elliptical in
shape, averaging 3 by 5 micrometers in size. The pores
tend to be displaced slightly into one hemisphere with
their long axis pointing toward the poles in a majority
of cases. The surface texture is psilate to minutely

granular. Hickory pollen was first described from the

139

Sucker Creek by Graham (1965). Observation suggests that
there may be two size classes, the first measuring 40 to
45 micrometers, typical of the figured specimen, and a
second larger form averaging approximately 65 micrometers,
typical of the form described by Graham. Only one species
of Carya is known from the macroflora but the habitats of
extant species would suggest that it is likely that other
species may have grown at a greater distance from the
depositional basin. Pollen evidence suggests that more
than one species is probably present. The pollen is con-
fined to the mesic forest zone and does not persist follow-
ing the floristic transition.

Location: Pb-9205-l V+8.9xH22.8

Genus JUGLANS L.
(Plate 9-7)

Grains of this genus are highly variable in size
ranging from 25 to 50 micrometers. The grains are spheri-
cal and multiporate with the pores tending to be concen-
trated in one hemisphere. The grains may appear somewhat
angular in polar view but there is little tendency for
them to orient preferentially in that configuration. The
pores are annulate but the extent of the development of
the annuli is variable. The exine is psilate with no con-
spicuous features. Pollen of this type was first described
from the microflora by Graham (1965). There is no macro-

fossil record of the genus in the flora although one

140

species of Juglans is recognized in the Blue Mountains and
Trout Creek floras of late Miocene age (Chaney and Axelrod,
1959). Pollen similar to that found in this study has
been described from the Oligocene (?) Brandon lignite of
Vermont (Traverse, 1955), the Miocene Kilgore flora of
Nebraska (MacGinitie, 1962), and the Miocene of Alaska
(Leopold, 1969). The variability of the Sucker Creek
material would suggest that more than one species may be
represented in the pollen record. The pollen is restricted
to the mesic forest zone and is not found above the flor-
istic transition.

Location: Pb-9157—2 V+2.5Hl9.5

Genus PTEROCARYA Kunth.
(Plate lO-4)

The grains are multiporate and somewhat angular in
outline. The pores are confined to the equatorial region
and are rarely displaced by any significant distance. The
number of pores varies but most grains range between 5 and
9. The grains average 35 micrometers in diameter and have
a psilate or finely granular surface texture. Graham (1965)
in his initial description of this pollen type in the
Sucker Creek microflora.stated that the grains have a finely
reticulate surface texture under oil immersion. The extent
to which this reticulum is developed appears to be highly
variable and the majority of the grains observed in this

study were not reticulate. Pterocary§_is a widespread

 

141

member of the microflora of the middle and late Tertiary
of the northwest and one species (3. mixta) is known from
the Sucker Creek macroflora. Pollen of the genus is found
throughout the Valley and Shortcut section but appears to
be limited to the mesic forest zone on the Rockville
section. The genus is endemic to eastern Asia and
according to Lee (1935) the nine species native to China
are primarily upland species growing at elevations from
4,000 to 6,000 feet.

Location: Pb-9272-4 V+7.8xH7.4

Family LEGUMINOSAE
(Plate 9-11)

Graham (1965) described a polyad which he considered
to represent the Leguminosae and also described both leaves
and seed pods which appeared to be referable to the family.
During the counting of palynomorphs in the upper part of the
Shortcut and Rockville sections a number of pollen masses
resembling polyads of the Leguminosae were noted. Unfor-
tunately, most of these specimens were poorly preserved and
are not very distinctive. The form illustrated is similar
- in many respects to polyads produced by the genus Acacia,
but the assignment is tentative. The specimen consists of
a closely packed polyad of grains with a total diameter of
28 micrometers. Little can be observed of the structure
of the individual grains. Despite their generally poor

preservation, the presence of a'number of different polyad

142

forms in the upper Shortcut and Rockville time would
suggest that several species belonging to the family were
preSent during the interval in question.

Location: Pb-9182-l V+0.3xH18.5

Family MALVACEAE
Genus SPHAERALCEA A. St.-Hil.
(Plate 9-10)

The grains are 30 to 40 micrometers in diameter,
spherical, and obscurely tricolpate with short furrows.
The exine, exclusive of the prominent spines, is coarsely
granular to finely reticulate. The spines range in length
from 2.5 to 3 micrometers and are as broad at their bases
as they are long. The spines are hyaline and somewhat
blunt at the tips but expand rapidly toward the base
flaring into a widened buttress with a striate appearance.
The grains are found throughout the study sections and
appear identical to those of the modern Sphaeralcea, a
genus of shrubs widely distributed in arid western North
America. According to LeOpold (1969), pollen of this type
is widely distributed in the middle and late Tertiary of
the western United States. Graham described a single grain
of this type under the Malvaceae in his treatment of the
flora.

Location: Pb-9311-3 V-l.7xH20.4

 

143

Malvaceae Pollen of Uncertain Generic Affinity
112221
(Plate 9-9)

These pollen grains are spherical with a fairly
uniform diameter ranging from 22 to 25 micrometers. The
grains are tricolpate with inconspicuous furrows. The
spines range from 3 to 3.5 micrometers in length with
hyaline blunt tips and somewhat flared bases with a striated
appearance. The base of the spines average approximately
2.5 micrometers in diameter. The exine varies from faintly
granular to finely punctate. This pollen type, previously
undescribed from the flora, can be placed with some confi-
dence in the family, but its generic affinities are not clear.

It has a close resemblance to pollen of the Malvastrum

 

type from the Middle Miocene Suntrana formation of the
Alaska Range (Leopold, 1969). These grains occur in small
numbers above the floristic transition in the upper Short-
cut and Rockville sections.

Location: Pb-9182-l V+9.le27.2

Family NYMPHAEACEAE
Genus NYMPHAEA L.
(Plate 10-2)
Rhizomes and leaves of plants apparently similar to
the living N. odorata have been described from various
Miocene floras in the Columbia Plateau region (Chaney and

Axelrod, 1959) but this is the first record of the genus

\ ( (I. l. I .' 111* t.- ‘.

 

144

from the Sucker Creek flora. The grains range from 50 to
60 micrometers in length and have a single longitudinal
operculum or furrow. The exine is thin and the grains are
usually found in a cdllapsed or torn condition. The exine
is hyaline and is covered with thin spines, the latter
averaging 3 micrometers in length and approximately 0.5
micrometers in diameter at their bases. The grains are
confined to the central part of the Valley section where
they presumably indicate a period of ponding.

Location: Pb-9272-4 V+9.3le7.6

Family NYSSACEAE
Genus NYSSA Gronov. ex L.
(Plate 10-3)
Grains of this type are ovate ranging in size from
30 to 35 by 40 to 46 micrometers. They are tricolporate
with the furrows extending well into the polar areas. The
pores have a thickened rim which gives the grains a char-
acteristic appearance in polar View. The exine is granular
in texture. Only two specimens of Nygga are known from the
macroflora. The first of these is a leaf, referred to N.
coEeana, which is similar to the modern N. syIVatica, and the

second is a fruit, N, hesperia, similar to the extant N.

 

aquatica. The equivalents of both modern species almost

 

certainly would have been growing not far from the basins
so that the paucity of leaves would indicate that the trees

were not common. The pollen alone cannot be related to

“If-’5..- 1

145

either form exclusively, although certain inferences may
be drawn based on the relatively small numbers occurring
in the samples studies. The grains occur only in the

mesic forest zone and are usually present only in highly
organic beds indicative of swamp-like depositional condi-
tions. Taggart (1967) in examining sediments taken from

Taxodium dubium - Nyssa aquatica swamps in southern

 

 

Illinois noted that Nyssa pollen, presumably that of N.

aquatica, was always very abundant when Taxodium and

 

 

N. aquatica were growing in close association and that

when N. aquatica was not present locally, the quantity of

 

Nyssa pollen was quite low. In the latter case, much of
the pollen record was probably derived from black gum

(N. sylvatica) trees which were scattered in small numbers
in the adjacent bottomland forest. In the Sucker Creek
flora, despite the fact that swamps were present, the
genus is not well represented in the pollen record,
strongly suggesting that the source plants were likely to
be scattered black gum trees growing in the bottomland
forest rather than water tupelo in characteristically
dense marginal stands around the swamp basins. Nyssa is

a common member of late Tertiary pollen floras from the

far west (Gray, 1964; Leopold, 1969), but this is the

first pollen record of the genus in the Sucker Creek flora.

Location: Pb-9157-2 V-4.2X8.1

146

F ami 1y ONAGRACEAE
Pollen of this family represents a new record for
the Sucker Creek flora. Two distinct pollen types were

recognized in the course of the present study.

Exes}.
(Plate 9-13)

The grains are triangular in polar View with short
furrows or long pores at the apices of the triangles.
The ends of the apices are inflated into pronounced vesti-
bula with a heavy granular structure. The main body of
the grain has a somewhat finer granular structure. The
base of each vestibulum is thickened forming a prominent
ring. In poorly preserved material the furrow area is
destroyed leaving the ends of the arms terminated in a
thick collar-like ring or flange. The grains are fairly
uniform in size ranging from 42 to 50 micrometers measured
from any one apex to the center of the opposite side.
Pollen of this type has been reported from a number of
Tertiary floras from various localities in North America
and it is known under a variety of names. Grains of this

type are commonly referred to Epilobium, a modern genus

 

which has pollen of similar morphology and size. Traverse
(1955) referred to similar material from the Brandon flora

as Jussiaea. The Sucker Creek material is similar morpho-

 

logically to the pollen of this genus but it is approxi-

mately 33 percent smaller than equivalent modern material.

“A! C‘Jlm’i- . u
C’. .

147

The form equivalent of this type is called Pollenites

 

oculis-noctis. The general morphology of the

 

material is quite common in the family as a whole and

although the material closely resembles Epilobium, a

 

careful study of the pollen of additional genera would be
required to confirm this assignment. This pollen type is
a relatively rare occurrence and is limited to organic
beds in the Valley and lower Shortcut and Rockville sec-
tions.

Location: Pb-9246-l V+9.8xH9.0

2x222.
(Plate 9-12)

The grains of this type are morphologically similar
to those of Type 1 but they are much larger. The
grains measure approximately 90 micrometers from an apex
to the center of an opposite side. Pronounced vestibula
with a granular to verrucate surface texture and slit-like
furrows are a prominant feature of this type. The body of
the grains is hyaline and the base of the vestibulum has
a thickened annular collar which persists when the pore
area has decayed. Although this type can be assigned to
the family with some certainty, there was no modern genus
or fossil form to which the specimens could be matched in

terms of both their size and morphology. Jussiaea pollen

 

is quite similar in overall size as is the pollen of

Oenothera, but none of the material examined from these

 

genera had the pronounced vestibular development, related

muff—"5W"? 11"

148

to the overall size of the grain, which is characteristic
of the fossil material. Pollen of this type was only found
in the organic interval at the middle of the Valley section
and it is possible that the source plant may have been an
aquatic herb.

Location: Pb-9158-l V-3.6xH15.2

Family SALICACEAE
Genus POPULUS L.
(Plate 10-7)

The grains are spherical and aporate with a
psilate to finely granular exine. They range in diameter
from 22 to 30 micrometers. The exine is thin and fragile
and the grains are often found in a torn and corroded con-
dition. This pollen type may be under-represented in
many samples due to the fact that the grains are easily
destroyed. The limited number of morphological features
makes it impossible to assign the material to any one
modern species. Three Populus species are known from the
macroflora and were apparently associated with the flood-
plain and lakeside communities. The ephemeral nature of
the pollen grains makes it likely that most of the pollen
in the record was derived from these local communities
rather than from aspens which may have been associated with
the successional sequence in the montane conifer forest
in the uplands.

Location: Pb-9158-l V-6.le18.9

149

Genus SALIX L.
(Plate 10-14)
Pollen of this type is ovate ranging in size from
17 by 25 to 50 by 70 micrometers. The grains are char-
acteristically tricolpate with a reticulate exine. There
are several Selig species which are very common in the
macroflora and the various pollen types undoubtedly
represent several tree and shrub species within the genus.
Pollen of this type was first described from the flora by
Graham (1965) and it occurs throughout the study sections.

Location: Pb-9157-6 V+5.2lel.0

Family TILIACEAE
Genus TILIA L.
(Plate 10-9)
Grains are tricolpate and sub-triangular in polar
View. The colpi are short and the margo is conspicuous. The
exine ranges from granular to finely reticulate. The
grains range in size from 32 to 40 micrometers. The first
description of pollen of this type in the Sucker Creek
flora was made by Graham (1965). The pollen is never
common and is confined to the mesic forest zone of the
Valley and lower Shortcut and Rockville sections.

Location: Pb-9308 V+9.0le9.5

150

Family ULMACEAE
Genus ULMUS L.
(Plate 10-12)

The grains are porate and sub-circular to slightly
angular in polar view. The grains range in size from 25
to 32 micrometers. The pores are equatorially arranged and
usually number four. The grains are rugulate giving them
a characteristic appearance. Graham (1965) was the first
to describe Nimgs pollen from the Sucker Creek microflora
and noted that it comprised approximately 20 per cent of all
the pollen counted despite the relatively poor representa-
tion of elms in the macroflora. Elm pollen is restricted
to the mesic forest zone of the Valley and lower Shortcut
and Rockville sections where it usually dominates the
deciduous tree pollen component unless exceeded in numbers
by peaks in alder. The poor macrofossil record indicates
that elms were not common along the streamside or lake
border communities bUt the large number of pollen grains
suggest that it was one of the more important genera in
the adjacent mesic bottomland and slope communities.
Morphologically,elm pollen may be confused with that of
Zelkova, a genus now endemic to the temperate deciduous
forests of eastern Asia. Zelkova is represented in the
macroflora by a single leaf and it is possible that some
pollen of this genus was tallied as glmgg, although it is
doubtful that Zelkova pollen constitutes an appreciable
percentage of the total.

Location: Pb-9158-7 V+l7.2leO.7

151

Spores and Pollen Grains of Uncertain
Taxonomic Position

A significant number of palynomorphs were encoun-
tered in the course of the study which could not reliably
be assigned to a family or, occasionally, even to a higher
category. Many of these grains were poorly preserved or
oriented or they had no outstanding features. Some of
these types are being illustrated and briefly described
in order to confirm their presence in the flora and in
the hope that later work may serve to indicate their taxo-
nomic affinities. All of these entities belong to the
Differentiated Unknowns category discussed in Chapter II
and are described under their survey designation consist-

ing of the letter U (unknown) followed by a number.

Ni;
(Plate 11-6)

These grains are circular in polar view, tricol—
pate, and have a rugulate surface texture. The colpi are
long and extend almost to the poles. The grains average
approximately 50 micrometers in diameter and, aside from
their coarser surface texture, they strongly resemble
.grains of the genus Mahonia. None of the Mahonia pollen
observed by the author had such a coarse surface and
pending the examination of additional material, the grains

were placed in the unknown category. Pollen of this type

152

is confined to the mesic forest zone of the composite
section.

Location: Pb-9157-l V-8.8xH12.3

N49
(Plate 11-3)
The grains of this type measure approximately 20 by
25 micrometers and are tricolporate with a reticulate sur-
face. The grains are found only in the Valley section and

resemble the grains of Sambucus, although the small amount

 

of material available and the occurrence of similar morph-
ological types in the Rosaceae makes detailed placement
impossible.

Location: Pb-9158-l V-3.2xH9.0

Néi
(Plate 11-1)

A single grain of this type, measuring 30 by approxi—
mately 45 micrometers, was recovered from the upper part of
the Rockville section. The grain is tricolpate and has a
well developed tectate exine. The grains resemble those
of BEBE although similar morphological types are produced
in the Euphorbiaceae.

Location: Pb-9l77-l V-4.2xH4.9

U63
(Plate ll-lO)
Pollen of this type is very common in the upper

Rockville and Shortcut sections. The grains are spherical,

153

tricolporate, and average 22 micrometers in diameter. The

exine consists of a well-developed columellate tectum.

 

Pollen of this type may be related to Artemisia since the
grains always occur together and their morphological fea-
tures are quite similar. However Artemisia grains identi-
cal to the fossil material could be found. Pollen of this

type is either rare or completely absent from beds below

the floristic transition but they may be found in fair
numbers in almost all productive samples above it.

Location: Pb-9l91-3 V5.8le7.l

U66a

 

(Plate 11-7)

Pollen of this type probably belongs in the
Compositae but the grains are usually poorly displayed
and it is not possible to be certain about some of the
details of their morphology. The pollen appears to be
tricolporate and is approximately 22 by 30 micrometers
in size. The exine is hyaline with faint longitudinal
lines. The grains are spiny with the spines are up to 2
micrometers in length. The grains are commonly tightly
folded and appear to be monosulcate in that orientation.
The grains are limited to the upper Shortcut and Rockville
sections.

Location: Pb-9l9l-3 V+5.8le7.l

154

N61
(Plate 11-12)
The pollen of this type is tricolpate and averages
17 micrometers in polar view. The surface is faintly
granular. This pollen type is confined to the upper
Shortcut and Rockville sections and its affinities are

completely unknown.

Location: Pb-9l96-l V+3.6xH15.9

NZ;
(Plate ll-ll)

This entity appears to be aporate and lacks any
observable scars. It is spherical and has a pronounced
reticulum formed by surface ridges. Several specimens
were recovered from the upper Rockville section.

Location: Pb-9l97-1 V+3.9xH22.0

212
(Plate 11-4)
These grains are tricolporate and measure approxi-
mately 20 by 27 micrometers. The grains have a small
polar index and the exine consists of a columellate tectum.
They are found in the upper Rockville and Shortcut sections

where they are often quite common.

Location: Pb-9197-1 V+11.0XH16.5

155

NZN
(Plate 11-15)

A single specimen of this type was noted in a sam-
ple from the upper Rockville section. It appears to be
spherical with a reticulate surface. No pores, furrows,
or scars were noted and the affinities of this specimen

are unknown.

Location: Pb-9l97-l V+9.6le7.5

N12
(Plate ll—8)

The grains of this type average 20 by 25 micrometers
in size. They are tricolpate and have a granular surface.
Except for their larger size, specimens of this type are
basically similar to those of U67. The grains are found
in the upper Shortcut and Rockville sections.

Location: Pb—9229—l V+8.0le4.5

N2;
(Plate 11-9)

A single grain of this type, measuring 42 by 50
micrometers, was recovered from the base of the Rockville
section. The grain is tricolpate with a pronounced beaded
reticulum. The character is the reticulum is much like
that of the Liliaceae but the presence of three furrows
eliminates that as a possibility. It is possible that the

fossil represents a large-grained form of Salix, similar

156 E

to a large grain described by Graham (1965) but further
assessment must await the isolation of additional material.

Location: Pb-9224-l V+9.le12.2

N22
(Plate 11-5)

The grain is tricolpate, measuring 55 micrometers
in diameter in polar View, with a well developed colum-
ellate exine structure that appears granular in surface
view. A single specimen of this type was recovered from
the lower Rockville section.

Location: Pb-9220-l V9.1xH15.4

U103

 

(Plate 11-13)

These plicate structures average 20 by 80 micro-
meters in length and are found in the upper Shortcut and
Rockville sections. Despite their distinctive appearance,
their biological affinities are unknown.

Location: Pb-9230-1 V-2.7XH26.3

U106

 

(Plate ll-2)

These pollen grains appear to be tricolporate and
measure approximately 30 micrometers in diameter in polar
view. The exine is thick and has a faintly striate appear-
ance. Pollen of this type has only been noted from the
lower Valley section and its affinities are unknown.

Location: Pb-9260-1 V+l.6xH5.4

157

U108

 

(Plate 11-16)
The grains of this type are tricolporate, average
35 to 40 micrometers in diameter in polar view, and have
a granular surface texture. This type occurs in the lower-
most Valley section and they may represent somewhat
corroded grains of Naggs.

Location: Pb-9263-l V+3.9xH24.7

U120

 

(Plate 10-15)

The grains of this type are tricolpate with a
diameter of approximately 60 to 70 micrometers in polar
view. The surface is somewhat granular and is covered
with scattered rod-like sculpturing elements with slightly
swollen tips. The overall aspect of the grains is similar
to some of the Cactaceae but no close counterparts of the
fossil material were observed that would support its
inclusion in that family. Grains of this type have only
been found in the middle of the Valley section.

Location: Pb-93ll-3 V-3.5xH23.9

U121

 

(Plate 11-14)
A single specimen of this type was isolated from
the middle Valley section. The grain is tricolpate and
the columellate exine appears granular in surface view.

The grain has a slight resemblance to those of Lonicera.

 

158

The grain is 55 micrometers in diameter which is consis-

tent with Lonicera but the details of the furrow margin

 

do not correspond precisely with the grains of that genus.

Location: Pb-9157-l V+2.2xH25.3

*g- “VJ-“*--ag
I n ' . i

LITERATURE CITED

159

LITERATURE CITED

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D. I. 1941. The concept of the ecospecies in
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Axelrod, D. I. and Bailey, H. P. 1969. Paleotemperature

Bailey,

analysis of Tertiary floras. Palaeogeogr., Palaeo-
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I. W. and Sinnott, E. W. 1915. A botanical index
of Cretaceous and Tertiary climates. Science 41:
831-834.

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160

161

Baldwin, E. M. 1964. Geology of Oregon. Univ. Oregon
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biologique. Soc. Biol. (Paris), C.R. et Mem.
96:695-696.

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596p.

Brooks, B. W. 1935. Fossil plants from Sucker Creek,
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Brown, C. A. 1960. Palynological techniques. Louisiana
State Univ. Press, Baton Rouge. 188p.

Bryan, K. 1929. Geology of reservoir and dam sites with
a report on the Owyhee irrigation project, Oregon.
U.S. geol. Survey Water Supply Paper 597-A. 89p.

Chaney, R. W. and Axelrod, D. I. 1959. Miocene floras of
the Columbia Plateau. Carnegie Inst. Wash. Pub.
617. 237p.

Chaney, R. W. and Sanborn, E. I. 1933. The Goshen flora
of west central Oregon. Carnegie Inst. Wash. Publ.
439:1-103.

Cope, E. D. 1883. On the fishes of the Recent and Pliocene
lakes of the western part of the Great Basin and of
the Idaho Pliocene lake. Proc. Phila. Acad. Nat.
Sci. 1883:134-167.

Corcoran, R. E. 1953. The geology of the east central
portion of the Mitchell Butte quadrangle, Oregon.
M.S. Thesis, Univ. Oregon, Eugene. 80p.

Dicken, S. N. 1955. Oregon geography. Edwards Bros.,
Ann Arbor, Mich. 127p.

Dilcher, D. L. 1969. Podocarpus from the Eocene of North
America. Science 164:299—301.

 

Doak, R. A. 1953. The geology of the Double Mountain -
Grassy Mountain area, Mitchell Butte quadrangle,
Oregon. M.S. Thesis, Univ. Oregon, Eugene. 94p.

162

Dorf, E. 1945. Observations on the preservation of plants
in the Paricutin area. Trans. Amer. Geophysical
Union. 26:257-260.

. 1969. Paleobotanical evidence of Mesozoic and
Cenozoic climatic changes. Proc. North Amer.
Paleobot. Conv., Part D: 323-346.

 

Erdtman, G. 1943. An introduction to pollen analysis.
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. 1966. Pollen morphology and plant taxonomy.
Angiosperms. Hafner Pub. Co., New York. 553p.

 

. 1969. Handbook of palynology. Hafner Pub.
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Evernden, J. F.; Savage, D. E.; Curtis, G. H.; and James,
G. T. 1964. Potassium-Argon dates and the Terti-
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945-972.

Graham, A. K. 1962. The role of fungal spores in palyno-
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. 1963. Systematic revision of the Sucker Creek
and Trout Creek Miocene floras of southeastern
Oregon. Amer. J. Bot. 50:921—936.

 

. 1965. The Sucker Creek and Trout Creek
Miocene floras of southeastern Oregon. Kent State
Univ. Bull. 53. 147p.

 

Gray, J. 1964. Northwest American Tertiary palynology -
the emerging picture. In: Cranwell, L. M. (ed.).
Ancient Pacific floras, the pollen story. Univ.
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121-30.

Gray, J. and Sohma, K. 1964. Fossil Pachysandra from
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1159-1197.

 

 

 

Jepson, W. L. 1960. A manual of the flowering plants of
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Johnson, T. W. and Sparrow, F. K. 1961. Fungi in oceans
and estuaries. J. Cramer, Weinheim. 668p.

Kirkham, V. R. D. 1931. Revision of the Payette and Idaho
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163

' 1’7‘"WT * 3
.", u

Kittleman, L. R., Jr. 1962. Geology of the Owyhee
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Knowlton, F. H. 1898. The fossil plants of the Payette
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Lee, Shun-Ching. 1935. Forest botany of China. Commer-
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Leopold, E. 1969. Late Ceonozoic palynology. In: Tschudy,
R. H. and Scott, R. A. Aspects of Palynology.
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Lindgren, W. 1898. The mining districts of the Idaho
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164

SchOpf, J. M. 1969. Systematics and nomenclature in paly-
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Sparks, D. M. 1967. Microfloral zonation and correlation
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1-107.

. 1955a. Occurrence of the oil-forming alga
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Wodehouse, R. P. 1933. Tertiary pollen - II. The oil
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574p.

 

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67-76.

APPENDIX

16.5

W‘_“m‘ffind .

APPENDIX

Detailed data on each of the three measured study
sections is included below. Data includes the position of
each unit, measured from the top of the measured section
and a description of the lithology of the unit in question.
If samples were collected in any particular unit, the sam—
ple number and its position, measured from the top of the
section, will appear in parentheses following the descrip-
tion of the overall rock units. If no data is included
for the position of a sample it represents a channel

sample of the entire rock unit.

ROCKVILLE SECTION
NW%NW% T28S R46E
Malheur County, Oregon

Feet from Top
of Section Lithology and Sample Data

 

 

0.0 - 6.0 Gray-brown to yellow-brown shale, somewhat
indurated, weathering yellow-brown on
exposed edges. Cedrela seeds. (Pb-9176
- 1.6', Pb-9177 - 5.2')

6.0 - 7.6 Fine light gray shale with no clear
bedding planes. (Pb-9178 - 6.4—6.8')

166

 

Feet from Top

of Section

 

10.2

10.3

11.5

12.1
12.7
13.1

13.8

16.9

17.0

18.2

18.3

20.3

22.5

9.3

10.2

10.3

11.5

12.1

12.7
13.1
13.8

16.9

17.0

18.2

18.3

20.3

22.5

22.6

167

Lithology and Sample Data

 

Gray shale weathering brown. Black
organic material on some bedding planes.
(Pb-9179 - 8.1-8.6')

Alternating laminations of coarse and
fine buff-green shale. (Pb-9180 - 9.4')

Fine gray shale with a faint maroon caste.
(Pb-9181)

Sandy yellow-orange to green shale with
gray interbedding, the latter with maroon
shading. (Pb-9182 - 10.3-10.5')

Fine gray shale with black organic frag-
ments on some bedding planes. (Pb-9183 -
11.5-11.6)

Sandy buff to green shale.
Fine gray shale.
Sandy yellow—brown shale.

Maroon to reddish-brown organic shale
with some interbedded yellow-green sand.
Stem fragments present. (Pb-9184 - 13.8-
13.9', Pb-9l85 - 15.0', Pb-9186 - 16.2').

Sandy yellow—brown shale with maroon
organic interbedding. (Pb-9187)

Maroon organic shale; fossil wood zone.

Maroon organic shale with iron staining
on partings.

Maroon lignite to organic shale, iron on
some partings. Some dark gray interbed-
ding, leaf and stem fragments. (Pb-9188 —
18.5', Pb-9l89 - 19.6')

Dark gray shale with somewhat coarser
interbedding. Weathers to a green-gray
clay. (Pb-9190 - 20.6')

Maroon organic shale with interbedded
layers of yellow-gray sandy shale.
(Pb-9192)

Feet from Top

of Section

 

22.6

27.2

29.0

34.6

39.7

52.7

58.0

79.5

80.0

80.7

82.1

82.5

82.6

27.2

29.0

34.6

39.7

52.7

58.0

79.5

80.0

80.7

82.1

82.5

82.6

83.6

168

Lithology and Sample Data

 

Sandy yellow to green—gray shale with
maroon-gray organic varves; organic
debris. (Pb-9193 - 23.4', Pb-9l94 -
25.7')

Sandy greenish shale with little organic
material.

Interbedded sandy yellow-green shale and
yellow sand. Iron staining and plant
fragments. (Pb-9195 - 29.4', Pb-9l99 -
33.7')

Angular, poorly sorted yellow—green sand.
(Pb-9196 - 35.7')

Yellow-green cross-bedded sand, weathers
reddish brown. (Pb—9197 - 44.5')

Sandy gray-green shale with irregularly
bedded organic layers.

Very light gray ash, weathers white.
Organic material on irregular bedding
planes. Cinder-like particles scattered
irregularly through the mass. (Pb-9200 -
69.5')

A continuation of the bed above but
somewhat more resistant with reddish
inclusions. (Pb-9201 - 70.8')

Less resistant white ash, reddish caste.

Fine yellow-green shale weathering to a
yellow clay. (Pb-9202 — 81.0')

Maroon to reddish brown shale, fissile,
many leaves, seeds, and insect parts.
(Pb-9203 - 82.4')

Maroon-gray organic shale, conchoidal
breakage pattern. (Pb-9204)

Vari-colored fissile shale; reddish-
maroon to yellow-gray. (Pb-9205 - 83.3')

m.“-

 

Feet from Top

of Section

 

83.6

86.4

87.5

87.6

87.8

88.0

90.8

91.1

91.6

91.7

92.6

92.9

93.7

95.6

95.7

86.4

87.5

87.6
87.8
88.0
90.8
91.1
91.6
91.7
92.6
92.9

93.7

95.6

95.7

95.9

169

Lithology and Sample Data

 

Dark gray organic shale with varves of
coarses yellow-green sand. (Pb-9206 -
84.9', Pb-9207 - 85.7', Pb—9208 - 86.2')

Brown to maroon-gray organic shale inter-
bedded with coarse xel shale or fine sand.
(Pb-9209 - 86.6', Pb-9210 - 87.3')

Maroon-gray organic shale with iron stains
on some bedding planes. (Pb-9211)

Brown organic shale.
Sandy green shale with organic partings.

Very dark gray organic shale with numerous
plant fragments on bedding planes.
(Pb-9212 - 89.0')

Brown and gray organic shale. (Pb-9213 -
90.9-91.0', Pb-9ll4 - 91.0-9l.1')

Poorly sorted angular orange to yellow-
green sand. (Pb-9215 - 91.2-9l.3')

Brown organic shale with plant fragments.
(Pb-9216)

Sandy yellow to buff-green shale.
(Pb-9217 - 92.1')

Fine gray shale weathering white-gray or
light brown on some planes. Slightly
indurated. (Pb-9218 - 92.7-92.8')

Dark gray shale, somewhat organic.

Light buff-gray shale with a slight maroon
caste. Upper 6 inches constitutes the
1eVel of leaf locality 7/21/70. Layer
coarsens toward bottom. (Pb-9224 - 94.0',
Pb-9220 - 95.0')

Fine green shale with white crystalline
inclusions. (Pb-9221)

Buff to reddish brown shale, organic
partings.

Feet from Top

of Section

 

95.9 j 96.9+

170

Lithology and Sample Data

 

Fine green shale. (Pb-9222 - 96.3')

Bottom of Measured Section

Feet from TOp

of Section

 

0.0

2.1

11.4

30.2

2.1

11.4

30.2

61.2

SHORTCUT SECTION
NW% SW% T15 R5W

Owyhee County, Idaho

Lithology and Sample Data

 

Alternating coarse to fine green-gray
shale. (Pb-9226 - 0.8')

Dark and maroon-gray organic shale; chert-
like nodules, sand, and mica flakes inter-
bedded. (Pb-9227 - 2.7', Pb-9228 - 3.3')

Yellow to yellow-green sand with some iron
staining.

Poorly consolidated greenish sand with
orange iron staining. (Pb-9229 - 6.4')

Angular yellow, poorly cemented sand that
is heavily iron stained. (Pb-9230 - 7.5-
7.6')

Weathered coarse yellow—green shale with
organic interbedding. (Pb-9231 — 8.3')

Angular, poorly consolidated yellow-
green-gray sand. (Pb-9232 - 9.5‘)

Poorly consolidated yellow-gray sand.
Upper two feet includes water-worn pebbles
up to 3" in diameter. Black carbonized
plant fragments, mostly stem segments,
scattered throughout. (Pb-9233 - 11.8',
Pb-9234 - 27.6', Pb-9235 - 29.6')

Light gray ash weathering white. Cinder
fragments and organic detritus on some
bedding planes. Some layers of maroon
organic material with chert-like nodules
at their centers. (Pb-9236 - 31.0',
Pb-9237 - 38.0', Pb-9238 - 29.0')

Feet from Top

of Section

 

61.2

62.7

64.7

68.0

69.0

70.3

71.1

71.6

72.3

72.4

72.8

73.0

75.9

82.1

62.7

64.7

68.0

69.0

70.3

71.1

71.6

72.3

72.4

72.8

73.0

75.9

82.1

89.3

171

Lithology and Sample Data

 

Orange to yellow-green shale weathering
to soft clay. (Pb-9239 - 61.7')

Fissile maroon-gray shale weathering
brown. Leaves, seeds, and insect parts.
Pb-9240 - 63.6')

Dark to maroon gray organic shale,
Conchoidal breakage, some slightly
coarser interbedding. (Pb-9241 - 67.0')

Yellow-brown to yellow-green shale with
maroon organic laminae. (Pb-9242 - 68.3',
Pb-9243 - 68.6-69.0')

Maroon organic shale drying gray. Unevenly
spaced varves of varying organic content.
(Pb-9244 - 69.5')

Buff-gray shale weathering into thin
sheets which turn brown at their edges.
Plant fragments. (Pb-9245 - 70.7')

Yellow-green to green shale with organic
partings. (Pb-9246 - 71.3')

Maroon-gray shale, thin lignite partings.
(Pb-9247 - 72.0')

Maroon organic shale with organic frag-
ments on bedding planes.

Green shale.

Maroon organic shale with organic frag-
ments on bedding planes. Fine gray
laminae. (Pb-9248 - 72.9-73.0')

Light to dark gray shale with organic
material on some partings. (Pb-9249 -
75.0')

Reddish brown lignitic to organic shale.
Shaley at the base becoming more lignitic
toward the top of the unit. (Pb-9250 -
76.3', Pb-9251 - 78.7', Pb-9252 - 81.5')

Yellow and gray sand, iron stained at
base. (Pb-9253 - 83.1')

Feet from Top
of Section

 

89.3 -

93.7 -

94.4 -

92.7

93.7

94.4

101.4

101.4 - 102.0

102.0 - 115.4+

172

Lithology and Sample Data

Coarse dark red-brown organic shale inter-
bedded by thin yellow sand layers.
(Pb-9254 - 89.7')

Green-gray-yellow sand.

Light to dark gray-brown shale with
organic debris on bedding planes.
(Pb-9255 - 94.0')

Green-gray-yellow sand.
Dark brown organic shale.

Angular, poorly consolidated yellow sand
with mica flakes. Irregularly spaced
thick organic partings. (Pb-9256 -
106.5' - no organic material; Pb-9257 -
106.7' - organic parting)

Base of Measured Section

Feet from Top
of Section

 

0.0 -

30.0 -

36.6 -

36.7 -

30.0

34.0

36.5

36.7

38.5

VALLEY SECTION
NE% T278 R46E

Malheur County, Oregon

Lithology and Sample Data

 

Light gray ash bed, weathers white.
Cinder particles and carbonized plant
fragments on some bedding planes.
(Pb-9302 - 5.0', Pb-9303 - 17.5',
Pb49305 - 29.0')

Light yellow-green shale with poorly
preserved plant fragments. (Pb-9274 —
32.0')

Very dark gray organic shale. (Pb-9275-
35.5')

Fine green-yellow-gray ashy shale.
Greenish gray to dark gray shale, high

organic content. Stump in place.
(Pb-9276 - 37.5')

Feet from Top
of Section

38.5

41.5

46.5

50.5

52.5

130.0

142.0

147.8

157.1

157.6

162.5

275.5

276.0

336.0

41.5

46.5

50.5

52.5

130.0

142.0

147.8

157.1

157.6

162.5

275.5

276.0

336.0

341.5

173

Lithology and Sample Data
Weathered greenish gray shale. (Pb-9277 -

Gray shale with maroon caste, highly
organic. (Pb-9273 - 45.5')

Dark organic shale, dries to a laminated
gray-maroon. (Pb-9272 - 49.4')

Light yellow—brown shale with black
organic material on some bedding planes.
(Pb-9271 - 51.7')

Light gray to maroon-brown shale. The
lower 10 - 20 feet represents the highly
fossiliferous Valley Plant Beds. (Pb-
9270 - 62.5', Pb-9269 - 77.5', Pb-9268 -
114.8', Pb-9267 - 115.6-115.9', Pb-9266 -
127.9')

Interbedded organic shales, mudstones,
sand. ”Upper Swamp Series." (Pb—9308 -
9324)

Sandy red-brown shale, organic material
on some bedding planes. (Pb-9265 - 146.8')

Interbedded organic shales, mudstones,
and sands. "Lower Swamp Series." (Pb—9280
- 9301)

Fine yellow sand with mica flakes and
organic debris. (Pb-9264)

Coarse brown shale with a high organic
content. (Pb-9263 - 161.3)

Olive to brown sand. Moderately consolid-
ated with some calcareous cement. Well—
developed joint pattern. (Pb—9262 -
195.0')

Dark gray impure limestone with high
organic content. (Pb-9261)

Continuation of the massive sand above.

Gray clay-shale. (Pb-9260 - 338.2')

Base of Measured Section.

P LATE S

174

175

P LATE l

A View of the valley system formed by the rocks of
the Rockville section. The photograph was taken facing NW
from the top of the knoll paralleling Sucker Creek Road
approximately 0.5 N of the junction of Sucker Creek and

Carter Creek Roads (Figure l).

.p m._.<._n_

 

177

PLATE 2

A view of the Shortcut section. The thick basal
sand and the white ash bed are particularly prominent in
this View. The Insect Bed is marked by the small terraces
in the beds which appear to lie directly below the white

cap of the knoll in the foreground.

 

.N uh<4m

:10!!! Lynx”?!

 

 
 
   

1.. .\ y

178

u...\.¢.. 7'“. . .. . . a
.
g .i7. .3 n .ywfiV d
.4 amy. a.

y . .I’ ~ .. . 0:. i .

O n

Figure

10
11
12
13
14
15
16
17
18

19

Fungal Type 1
Fungal Type 3
Fungal Type 4
Fungal Type 12
Fungal Type 7
Fungal Type 9
Fungal Type 6
Fungal Type 15
Algal Type 4
Fungal Type 16

Alternaria sp.

 

Fungal Type 19
Fungal Type 14
Algal Type 3
Fungal Type 5
Algal Type 1
Algal Type 2

Botryococcus sp.

 

Fungal Type 21

All illustrations at lOOOX.

179

PLATE 3

A-

 

 

 

 

*— *‘—#——--fl___-

180

PLATE 3.

O® Q@ ()6) 9G '36)

 

181

 

 

 

PLATE°4

Figure

1 Polypodiaceae, Type 2

2 Polypodium sp.

3 Lycopodium, Type 1

4 Monolete Type 4

5 Monolete Type 2

6 Trilete Type 2

7 Polypodiaceae, Type 1

8 Osmunda sp.

9 Lycopodium, Type 2
10 Trilete Type 1

All illustrations 1000X.

fl ,‘v fl-” v

 

 

182

PLATE 4.

 

183

PLATE 5

Figure
1 Abies, Type 1
2 Abies, Type 2

All illustrations 1000X.

4"me
"w—'—__-—\'

 

 

#*-
*.
Oil-M

 

I
no

r

184
PLATE 5-

4’7" u-JJ'Q‘ ‘
' -:‘.~ I 3
. Q.’ a '.
\ ' ‘
’2 11.3%,} .’

 

185

PLATE 6
Figure
1 Picea, Type 1
2 Picea, Type 2 (740K)

All illustrations 1000X unless otherwise indicated.

186

PLATE 6

 

Figure

1 EEESE sp.

2 PigNs, Type 1
3 Piflgs, Type 6
4 BEEEEI Type 4
5 EEEEEI Type 5
6 REESE! Type 2
7 Taxodiaceae

8 Podocarpus sp.

 

All illustrations 1000X.

187

PLATE 7

188

PLATE 7.

 

Figure

10
11
12
13
14
15
16
17
18
19
20

21

522E! Type 1
A223, Type 2
£11113. sp-
Betula sp.

Castanea sp.

Carpinus sp.
Carya sp.

189

PLATE 8

Chenopodiaceae, Type 1

Sarcobatus sp.

 

Artemisia, Type 1
Artemisia, Type 2
Compositae, Type
Compositae, Type
Compositae, Type
Compositae, Type
Compositae, Type
Compositae, Type
Ericaceae

Shepherdia sp.

 

Elaeagnus sp.

Ericaceae

All illustrations 1000X.

5

6

1

190

PLATE 8.

 

 

 

Figure
1 Ngggs sp.
2 Gramineae, Type 1
3 Gramineae, Type 2
4 Gramineae, Type 3
5 Iiex, Type 1
6 llex, Type 2
7 Juglans sp.
8 Liquidambar sp.
9 Malvaceae, Type 1
10 Sphaeralcea sp.
11 Leguminosae
12 Onagraceae, Type 2
13 Onagraceae, Type 1

All illustrations 1000X.

191

PLATE 9

192

PLATE 9.

 

Figure

10

11

12

13

14

15

193

PLATE 10

Mahonia sp.

Nymphaea sp.
Nyssa sp.

Pterocarya sp.

Potamogeton sp.

 

Caprifoliaceae, Type 1
Populus sp.
Pachysandra sp.

3.1.12 89-

$213112 sp.

Quercus sp.

Ill—mas. sp-

Quercus sp.

:81le SP-

Unknown 120

All illustrations 1000X.

 

194

PLATE 10.

 

 

Figure

10

11

12

13

14

15

16

Unknown

Unknown

Unknown

Unknown

Unknown

Unknown

Unknown

Unknown

Unknown

Unknown

Unknown

Unknown

Unknown

Unknown

Unknown

Unknown

195

PLATE 11

61

106

49

72

93

13

66a

79

92

63

71

67

103

121

78

108

All illustrations 1000X.

196

PLATE 11.

 

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