Palynological Evaluation of

Cedar Muntain and

Burro Canyon Formations,

Colorado Plateau

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281
Palynological Evaluation of 

Cedar Mountain and 

Burro Canyon Formations, 

Colorado Plateau

By R. H. TSCHUDY, B. D. TSCHUDY, and L. C. CRAIG

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281

A description of the rocks and age determinations of 

the formations based upon their pollen and spore content

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1984
UNITED STATES DEPARTMENT OF THE INTERIOR 

WILLIAM P. CLARK, Secretary

GEOLOGICAL SURVEY 

Dallas L. Peck, Director

Library of Congress Cataloging in Publication Data

Tschudy, Robert H.

Palynological evaluation of Cedar Mountain and Burro Canyon Formations, Colorado Plateau. 

(Geological Survey Professional Paper 1281) 

Bibliography: 24 p. 

Supt. of Docs. No.: 119.16:

1. Palynology Colorado Plateau. 2. Paleobotany Cretaceous. I. Tschudy, Bernadine D. II. Craig, L. C. 

III. Title. IV. Series.

QE993.T746 1984 561'.13'097881 82-600300

For sale by the Branch of Distribution, U.S. Geological Survey 

604 South Pickett Street, Alexandria, VA 22304
CONTENTS

Page

Abstract .............................................. 1

Introduction ............................................ 1

Rock units ............................................. 1

Cedar Mountain Formation ................................. 2

Burro Canyon Formation .................................. 2

Distribution, stratigraphic relations, and interpretation .................... 4

Methods of sample treatment .................................. 4

Location of productive samples ................................. 6

Cedar Mountain Formation ................................. 6

Burro Canyon Formation .................................. 6

Upper horizon ...................................... 6

Lower horizon ...................................... 7

Palynological analysis Cedar Mountain Formation ....................... 7

Landmark evolutionary events in the development of Angiosperm pollen ....... 9

Age of the upper part of the Cedar Mountain Formation ................ 10

Palynological analysis Burro Canyon Formation ........................ 11

Upper horizon ......................................... 11

Palynomorph recovery from upper horizon samples ................. 13

Lower horizon ......................................... 13

Palynomorph recovery from lower horizon samples ................. 15

Age of the upper part of the Burro Canyon Formation ................. 15

Conclusions ............................................. 19

References cited .......................................... 19

ILLUSTRATIONS

[Plates follow index]

PLATES 1-4. Photographs of palynomorphs from Cedar Mountain Formation .

5-9. Photographs of palynomorphs from Burro Canyon Formation . 

FIGURE 1. Graphic sections showing stratigraphic positions of palynomorph collections .............

2. Map of Colorado Plateau area .......................................

3. Histograms showing percentage distribution of major microfossil groups, Cedar Mountain sample .

4. Photomicrographs of organic material from Burro Canyon upper horizon samples ..........

5. Photomicrograph of thin section of Burro Canyon rock showing bedded nature of organic material 

6-8. Histograms showing gross palynomorph recovery from:

6. Burro Canyon samples upper horizon ..............................

7. Burro Canyon upper and lower horizons a comparison .....................

8. Selected intervals Burro Canyon lower horizon .........................

Page

3

5

8

12

13

14

14

16

TABLES

TABLE 1. Relation of geochronologic terms used and age estimates of boundaries in millions of years before present 

2. Stratigraphic ranges of Burro Canyon palynomorph species ............................

Page 

2

18

III

PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND 

BURRO CANYON FORMATIONS, COLORADO PLATEAU

By R. H. TSCHUDY, B. D. TSCHUDY, and L. C. CRAIG

ABSTRACT

By lithologic fades change the Cedar Mountain Formation of eastern Utah passes laterally into the Burro Canyon Formation of western Colorado. Both formations lie between the Dakota Sandstone and 

Morrison Formation. Few fossils have been found in the Cedar Mountain and Burro Canyon Formations, and consequently the age span 

attributed to these formations has been uncertain.

The overlying Dakota Sandstone in these two areas is palynologically of early Cenomanian age. The first occurrence of the angiosperm 

fossil pollen, Nyssapollenites albertensis Singh, found in the basal 

Dakota, is proposed as the palynological indicator of the Early-Late 

Cretaceous boundary in the Western Interior. Palynomorphs found 

in the upper parts of both the Cedar Mountain and Burro Canyon 

Formations are more advanced than are those found in the upper 

part of the Morrison Formation in the same general area. Consequently, the upper parts of the Cedar Mountain and Burro Canyon 

Formations that yielded palynomorphs are palynologically of Early 

Cretaceous age.

The palynomorph assemblage found in the upper part of the Cedar 

Mountain Formation date this horizon as late Albian. The Burro Canyon assemblages were somewhat less distinctive, exhibiting evidence 

of sequential biofacies changes, and one sample exhibited an unusual 

lithotype somewhat suggestive of algal origin. Nevertheless, the 

palynological age of the upper part of the Burro Canyon Formation 

is clearly older than that of the Cedar Mountain sample. The age 

of the Burro Canyon sample is estimated to be Aptian to early Albian 

with the possibility of being as old as Barremian (latest Neocomian). 

Thus, samples from the upper parts of these two physically equivalent 

formations show a difference in age. We speculate that pre-Dakota 

erosion may have removed beds equivalent to the upper Cedar Mountain at the Burro Canyon locality, and that the Neocomian may be 

represented in the still undated lower parts of the Cedar Mountain 

and Burro Canyon Formations.

INTRODUCTION

The Burro Canyon Formation of western Colorado 

and the physically equivalent Cedar Mountain Formation of eastern Utah, both of Early Cretaceous age, 

have received considerable geologic attention since 

their definition by Stokes and Phoenix (1948) and 

Stokes (1944, p. 965-967). Both formations have proved 

valid as mappable units, yet concern remains about the 

age and detailed relations of these formations, both to 

the underlying Morrison Formation of supposed Late 

Jurassic age and to the overlying Dakota Sandstone of 

earliest Late Cretaceous age. All students of the Burro 

Canyon and Cedar Mountain Formations agree that, at

least in part, the formations pass laterally by lithologic 

change into each other.

Upper parts of the Burro Canyon and Cedar Mountain have been interpreted as passing laterally into the 

overlying Dakota Sandstone (Young, 1960, p. 158) and 

as separated from it by an erosional disconformity 

(Craig and others, 1955, p. 161; Carter, 1957, p. 313). 

The Burro Canyon has also been interpreted as intertonguing with the underlying Brushy Basin Member of 

the Morrison Formation (Craig and others, 1961, p. 

1583) and as separated from the Morrison by a disconformity (Young, 1960, p. 169). These differences of interpretation serve to emphasize the importance of age 

determinations from either the Cedar Mountain or 

Burro Canyon Formations and adjoining beds. Unfortunately, both the Cedar Mountain and Burro Canyon 

Formations contain few fossils. Young (1960, p. ISO181) summarized the knowledge of the limited invertebrate fauna and megaflora. The Aptian or Albian Age 

(table 1) determined for these fossils accounts for the 

assignment of the Burro Canyon and Cedar Mountain 

to the Early Cretaceous.

The recognition of palynomorphs in samples from the 

Burro Canyon led to the hope that more could be 

learned from the plant microfossils about the ages of 

the Burro Canyon and Cedar Mountain Formations and 

adjacent beds. Considerable search for likely fossiliferous beds resulted in the collection of numerous samples, 

most of which proved to be barren of palynomorphs. 

A few samples, however, contained suites of 

palynomorphs, and these new data and the interpreted 

ages are presented in this report.

Acknowledgments. We thank Sharon Van Loenen 

for her assistance in the preparation of illustrations, 

the photography of specimens, and other aspects of the 

preparation of this manuscript.

ROCK UNITS

A summary of the characteristics of the Cedar Mountain and Burro Canyon Formations near the fossil sites 

follows; figure 1 shows the stratigraphic position of the 

productive palynomorph collections discussed in this 

paper.
PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

TABLE 1. Relation of geochronologic terms used in this report and 

age estimate of boundaries in millions of years before present, 

based on Lanphere and Jones (1978)

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CEDAR MOUNTAIN FORMATION

The Cedar Mountain consists of a relatively thin basal 

conglomeratic sandstone unit, the Buckhorn Conglomerate Member, and a relatively thick upper shale unit, 

the shale member. The shale member consists of silty 

to sandy swelling mudstones that show relatively thick 

color zones of pastel shades. Some of the mudstone 

units contain abundant limestone nodules that cover the 

weathered slopes of the member. Minor constituents 

of the member are thin, broadly lenticular limestone 

beds, and a few sandstone units, which are generally 

cross bedded, may contain lenticles of granule to pebble 

conglomerate, and appear fluvial in origin. The carbonaceous mudstone from which the palynomorphs were 

collected is almost unique in the Cedar Mountain.

The Cedar Mountain differs from the Burro Canyon 

in that the shale member consists dominantly of pastelcolored claystone, including purples and reds, as well 

as green; it is composed of swelling clays and it generally contains an abundance of limestone nodules that 

cover the weathered slopes. The Cedar Mountain Formation differs from the underlying Brushy Basin Member of the Morrison Formation in that it lacks the brilliant colors of the Brushy Basin, it lacks the distinct 

color banding, and it has abundant limestone nodules. 

The Cedar Mountain is distinguished from the Dakota 

Sandstone by the general absence of carbonaceous 

layers in the mudstone of the Cedar Mountain and the 

presence of carbonaceous shale and plant remains in 

the sandstone beds of the Dakota.

The palynomorph collections reported here come from 

a single carbonaceous unit near the top of the formation 

(fig. 1) in the SEVtSWV*, sec. 17, T. 19 S., R. 9 E., 

Emery County, Utah. The locality is about 16 km 

southwest of the type locality of the Cedar Mountain 

Formation (Stokes, 1952, p. 1773). This carbonaceous 

unit also has provided a small invertebrate and megaflora suite reported by Katich (1951, p. 2093-2094).

BURRO CANYON FORMATION

The Burro Canyon is a sequence of alternating lenticular conglomeratic sandstone beds and variegated, 

mostly greenish-gray, nonswelling mudstone beds. The 

sandstone units generally dominate in the lower part 

of the formation, whereas the mudstone is more abundant in the upper part of the formation. Minor rock 

components are limestone and chert beds.

The formation is distinguished from the underlying 

Brushy Basin Member in that it consists of coarse, generally conglomeratic, sandstone and interbedded dominantly greenish-gray mudstone, composed of nonswelling 

clay. The Brushy Basin contains only a few conglomeratic sandstone beds, particularly in its upper part, and 

is composed dominantly of alternating red, green, and 

gray mudstone that contains swelling clay, and forms 

distinctly color-banded outcrops. The Burro Canyon 

Formation is distinguished from the overlying Dakota 

Sandstone by the greenish mudstone and by the absence of carbonaceous material and organic-rich shale, 

lignite, or coal. The Dakota consists of interbedded 

sandstone and carbonaceous shale; the sandstone is in 

part conglomeratic and generally contains much carbonaceous debris and common impressions of twigs, stems, 

and branches.

The collections of palynomorphs reported here came 

from two carbonaceous shale units (fig. 1) in the upper 

shaly part of the Burro Canyon exposed in a small 

tributary of Disappointment Creek in the NEV4, sec. 

11, T. 43 N., R. 18 W. The fossil locality is 6.2 km 

southeast of the type locality of the Burro Canyon Formation (in Burro Canyon, sec. 29, T. 44 N., R. 18 W., 

San Miguel County, Colo.). Neither of the carbonaceous 

units have been recognized at the type locality. The 

upper carbonaceous unit is the same unit that has pro-
ROCK UNITS

Emery County, Utah

Sec. 34, 35, T. 18 S., R. 9 E.

Sec. 3, 4, T. 19 S., R. 9 E.

Dakota Formation

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EXPLANATION

Conglomeratic sandstone

Crossbedded sandstone

~ I Variegated mudstone

Carbonaceous mudstone 

or shale

Limestone

Cherty or silicified 

limestone

Calcareous mudstone 

or shale

Limestone nodules* 

Fossil-bearing layers

FIGURE 1. Graphic sections showing stratigraphic positions of palynomorph collections. A, Section 

of Cedar Mountain Formation near type locality of formation; fossil-bearing carbonaceous lens 

sketched on basis of position beneath the Dakota Sandstone at fossil locality. B, composite 

section of Burro Canyon Formation measured at fossil localities.
PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

duced a small invertebrate fauna and megaflora reported by Simmons (1957, p. 2525- 2526).

DISTRIBUTION, STRATIGRAPHIC 

RELATIONS, AND INTERPRETATION

The Burro Canyon formation is recognized over a 

broad area in southeastern Utah and western Colorado 

(fig. 2), and recently the name has been extended to 

similar rocks occupying a similar stratigraphic position 

in the Chama basin of north-central New Mexico 

(Saucier, 1974).

The southern limit of the Burro Canyon is an erosional limit where the Burro Canyon is cut out by the 

regional unconformity at the base of the overlying 

Dakota Sandstone. This limit is along a northwesttrending line that passes near the Four Corners. South 

of this limit, the pre-Dakota unconformity progressively 

bevels the Morrison Formation and older formations 

southward.

To the east, beds equivalent to the Burro Canyon 

are believed to be present in central and eastern Colorado (Lytle Formation of Dakota Group along the 

Front Range foothills and Lytle Sandstone Member of 

Purgatoire Formation in southeast Colorado). The 

Burro Canyon itself reaches a poorly known pinchout 

along an irregular north-south line extending from 

northwestern Colorado to northwestern New Mexico 

(fig. 2). The nature of this pinchout is uncertain. In 

part it is probably the result of pre-Dakota erosion, 

but in part it also may be due to depositional thinning 

of the formation. In the poor exposures along the few 

outcrop belts that cross the pinchout, the sandstone 

beds in the Burro Canyon appear to thin as the pinchout 

is approached. However, pre-Dakota erosion seems the 

most important factor in the pinchout of the formation.

The Cedar Mountain Formation is recognized over 

much of south-central and northeastern Utah and northwestern Colorado. The southern limit is south of the 

Henry Mountains and is an erosional limit along which 

the Cedar Mountain is cut out by the erosional unconformity at the base of the Dakota. The western limit 

is poorly known but it extends beneath the high 

plateaus of central Utah. To the north, the formation 

is identified to the Wyoming State line in both northeastern Utah and northwestern Colorado. Equivalent 

beds in Wyoming are included in the Cleverly Formation.

The arbitrary lateral limit between the Burro Canyon 

Formation and the Cedar Mountain Formation is placed 

along the Colorado River in Utah (Stokes, 1952, p. 

1774), although for a distance of about 40 km west of 

the river the characteristics of the two formations intermingle.

To the north in Colorado, the Burro Canyon Formation passes laterally into the Cedar Mountain Formation. In this area north of the Colorado River, the line 

of demarcation between the Burro Canyon and Cedar 

Mountain is placed where Burro Canyon characteristics 

give way to Cedar Mountain characteristics in the subsurface as interpreted from drillhole logs.

Based on thickness, percentage of sandstone, pebble 

size, and limited current-direction studies, the Burro 

Canyon and Cedar Mountain are interpreted as sediments from two alluvial systems deposited across a 

broad even surface on top of the Morrison Formation; 

in many respects they appear to represent a continuation of Morrison deposition. The major source for the 

Burro Canyon was southwest of the Four Corners, 

perhaps in southern Arizona. Burro Canyon deposits 

were spread northward and eastward from a major depositional axis along the southern part of the Utah-Colorado State line. The source for the Cedar Mountain 

Formation was somewhere west of the high plateaus 

in central Utah, and Cedar Mountain deposits were 

spread eastward.

METHODS OF SAMPLE TREATMENT

Samples were first cleaned, then broken into fragments about 1-5 mm (millimeters) in diameter. 10-20 

g (grams) of broken rock were placed in plastic beakers 

and tested for the presence of carbonates. If carbonates 

were present, the samples were then treated with 10- 

percent HC1 to remove carbonates; otherwise they were 

treated directly with hydrofluoric acid to disaggregate 

and partly dissolve the inorganic matrix. After thorough washing, the centrifuged residue was treated with 

the oxidizing Schulze1 solution (HN03 + NaCl)03). After 

washing, the acid humates were solubilized and removed by a short treatment with 10-percent NaOH solution. Pollen and spores (and insoluble organic matter) 

were concentrated from the residue by flotation in zinc 

bromide solution (specific gravity about 2.0) and then 

"panned" by means of the technique suggested by 

Funkhouser and Evitt (1959). The palynomorphs were 

then stained with Bismark Brown, if necessary, and 

then mixed with Vinylite AYAF in 90-percent alcohol 

(polyvinyl acetate plastic, refractive index 1.466).

Several drops of the palynomorph-plastic mixture 

were placed on a 22x40 mm cover glass and another 

cover glass was placed on the mixture, thus making 

a "sandwich." After the plastic had spread evenly to 

the margins, the cover glasses were separated by sliding them in opposite directions lengthwise in much the

"Trade names used in this paper are for descriptive purposes only and do not constitute 

endorsement by the U.S. Geological Survey.
METHODS OF SAMPLE TREATMENT

111° 110

FIGURE 2. Map of Colorado Plateau area showing fossil sample localities, sample numbers, and distribution of Cedar Mountain (Kem) 

and Burro Canyon (Kbc) Formations. Zero line marks pinchout of Burro Canyon and Cedar Mountain Formations (dashed where 

uncertain). Dotted line is arbitrary line separating areas in which Burro Canyon and Cedar Mountain are recognized.
PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

same manner as a blood smear is made. After the film 

on the cover glasses had dried for a few minutes on 

a warming plate, the cover glasses were inverted and 

mounted on slides using Histoclad resin. This method 

provides a thin, evenly dispersed film of pollen and 

spores in a mountant of favorable refractive index. It 

serves to anchor the fossils close to the cover glass so 

that they can be examined conveniently even under 

high-power oil-immersion lenses.

Slides are identified by locality number (D5510-A), 

and slide number D5510-A (1) or D5510-A (2); and on 

occasion processing sequence is also included as preparation 1 (prep. 1, prep. 2) and fraction heavy fractions, 

fine fraction (Hvs; fines.): for example, D5785-A, prep. 

4, Hvs., slide 5.

Minor modifications of oxidation time, cleaning procedures, and staining were tried with some success in 

efforts to improve the quality of some preparations.

LOCATION OF PRODUCTIVE SAMPLES 

CEDAR MOUNTAIN FORMATION

Two Cedar Mountain samples were obtained from the 

locality known as the Stokes-Katich locality (Simmons, 

1957, p. 2527). Samples were taken from a 1.5-m-thick, 

dark-gray calcareous shale outcrop in a cliff. The outcrop was about 13.9 m below the Dakota contact. The 

lower sample, consisting of gray calcareous siltstone interspersed with small calcite crystals, was barren of 

palynomorphs. The upper sample, consisting of darkgray laminated shale and black claystone, was productive and was assigned a USGS paleobotany locality 

number as indicated below:

USGS

paleobotany

loc. No.

Field No. Locality

D5785 3RT-77-7 SE1/4SW1/4 sec. 17, T. 19 S., R. 9 E., 

1A mi west of the junction of Rock 

Canyon Creek and Cottonwood 

Creek, Emery County, Utah. 

(Stokes-Katich locality in Simmons, 

1957, p. 2527).

BURRO CANYON FORMATION 

UPPER HORIZON

Productive samples were obtained from two horizons. 

The upper horizon consisted of a 1.5-m-thick layer of 

black fissile shale located 7.3 m below the base of the 

Dakota Sandstone and immediately above a prominent 

limestone ledge. This is the same general locality from 

which fossils were collected by Stokes (1952) and the 

identical locality visited by G. C. Simmons and D. R.

Shawe, and later revisited by L. C. Craig and others 

(Simmons, 1957, p. 2525). Several collections for 

palynological examination were taken from this locality 

during the summer of 1976. The yield of palynomorphs 

from these samples was so poor that resampling was 

conducted at the same site and along the lateral extent 

of the outcrop in the summer of 1977 and again in 1978. 

Sample number and localities for the upper horizon of 

the Burro Canyon Formation are listed below:

USGS

paleobotany

loc. No.

Field No. Locality

D5510-A RT-76-6 1/4NW1/4NE1/4 sec. 11, T. 43 N., R. 18 

W., in northwest wall of an intermittent stream bed about 330 m south 

of its junction with Disappointment 

Creek, Hamm Canyon quadrangle, 

San Miguel County, Colo. Approximately 1.5-m-thick ledge of black fissile shale, 7.3 m below Burro CanyonDakota contact. Sample 25 cm above 

limestone ledge at base of shale.

D5510-B RT-76-7 Same locality as D5510-A, 31 cm above 

limestone ledge.

D5510-C RT-76-8 Same locality as D5510-A, 61 cm above 

limestone ledge.

D5786-A RT-77-15 Same locality as D5510-A, top part of 

limestone ledge.

D5786-B RT-77-16 90 m S. 5° E., from locality of D5510-A, 

along strike of black fissile shale. 1- 

cm-thick basal siltstone layer immediately above limestone ledge.

D5800 RT-77-17 Same locality as D5786-B. Black, wet 

mudstone, 60 cm above limestone 

ledge.

D5801 RT-77-18 Same locality as D5786-B. Black fissile 

shale with limestone concretions 18 

cm above limestone ledge.

D5802 RT-77-19 S. 60° W., 200 m from sample D5801; 

sample from northwest side of drainage. Composite sample from 1.5-mthick black fissile shale.

D5974 RT-78-18 NW corner sec. 13, T. 43 N., R. 18 W., 

along unimproved road, Hamm Canyon quadrangle, San Miguel County, 

Colo. About 1.5-m-thick black fissile 

shale. Same horizon as previous 

Burro Canyon samples, but only 3 m 

below the Dakota contact.

The upper horizon of black fissile shale has been 

traced several kilometers to the northwest and to the 

southeast of the original locality, but is apparently absent from the type locality of the Burro Canyon Formation in Burro Canyon near the village of Slick Rock, 

Colo., sec. 29, T. 44 N., R. 18 W., San Miguel County, 

Colo.
LOCATION OF PRODUCTIVE SAMPLES

LOWER HORIZON

In 1976 during the course of recollecting samples from 

the localities just described, a black limy shale horizon 

was found about 10.4 m below the base of the 1.5-mthick black fissile upper-shale horizon. This sample 

yielded a much better assemblage of palynomorphs than 

was obtained from the upper fissile-shale horizon. The 

sample consisted of two lithotypes a fine-grained, 

hard, calcareous black shale, and a black, soft, friable 

shale containing small calcite crystals. Palynomorph 

yield from the two lithotypes was distinctly different, 

suggesting that biofacies near the site of deposition had 

changed. The site was recollected in 1978. Six samples 

were collected from an 87-cm interval (fig. 8). Four of 

these samples were productive and were given USGS 

paleobotany locality numbers as indicated below:

USGS

paleobotany

loc. No.

Field No. Locality

D5803

D5972-A,B,

C,D 

D5973

RT-77-20 SW1/4NE1/4 sec. 11. T. 43 N., R. 18 W., 

at approximate location of bench 

mark 5641, Hamm Canyon quadrangle, 1960, 10.4 m below base of 

upper fissile-shale horizon. Sample included two lithotypes; soft, black friable shale with small calcite crystals, 

and hard, dark-gray calcareous shale.

RT-77-20 Same locality as D5803. See figure 8.

RT-78-16 Same locality as D5803 but 10.2 m north 

along strike of dark-gray and black 

outcrop. Sample from bentonite zone, 

friable black shale that grades upward into dark-gray to black limestone. Composite sample from 30-cm 

interval.

The lower horizon was traced about 150 m along the 

wash, but apparently is not present or is covered elsewhere.

PALYNOLOGICAL ANALYSIS CEDAR 

MOUNTAIN FORMATION

Reports of fossils from the Cedar Mountain Formation are exceedingly sparse. The pertinent information 

concerning those few fossils found is presented by Simmons (1957) who listed fossils from two localities. The 

first locality, the socalled Stokes-Katich locality, is the 

same locality mentioned previously that yielded the 

palynomorphs in the present study. Fossils found include Eupera onestae McLearn, a fresh-water

pelecypod of Aptian Age, Tempskya minor Reed and 

Brown, a tree fern trunk, known from the Aspen Shale 

(Albian Age) Wyoming and Idaho, ostracods, and 

ganoid fish scales. "The second locality is in sec. 22, 

T. 22 S., R. 20 E., on the southwest flank of the Salt 

Valley anticline, Grand County, Utah" (Simmons, 1957, 

p. 2527). This locality yielded ostracods, gastropods, 

microfossil material, and the charophyte Clavator harrisi Peck.

The microfossil material was examined by R. E. Peck 

who stated: "All of these are common fossils in the Gannett Group, the Cleverly of northwestern Wyoming, 

and the limestones in the upper Kootenai of Montana. 

Clavator harrisi Peck is common in the Trinity of the 

Gulf Coast. None of these species occurs in the Morrison of the Front Range of Colorado, in eastern Wyoming or in the Black Hills. Their occurrence is an excellent indication of the Lower Cretaceous age of the formation" (in Simmons, 1957, p. 2527). The purported 

age of the Gannett Group is Early Cretaceous, of the 

Cleverly and Kootenai Formations is Aptian, and of the 

Trinity Group of the Gulf Coast, is Aptian to early Albian. "In view of the identifications, an Early Cretaceous age seems assured for the shale member of the 

Cedar Mountain Formation" (Simmons, 1957, p. 2527).

Angiosperm wood was collected from the Cedar 

Mountain Formation near Castle Dale and Ferron, 

Utah by Thayn (1973). Genera found were Icacinoxylon, previously known only from the Tertiary of 

Europe, and Paraphyllanthoxylon, known from the 

Cretaceous of Arizona, Idaho, and Alabama. However, 

these fossils shed no additional light upon the age of 

the Cedar Mountain Formation.

The samples collected for our study were examined 

palynologically in an attempt to obtain a more definite 

age determination and to verify the reported correlations of the Cedar Mountain and Burro Canyon Formations (Simmons, 1957; Craig and others, 1955).

Palynomorphs were poorly preserved and somewhat 

sparse, requiring the intensive examination of many 

slides in order to obtain a significant assemblage. The 

palynomorph assemblage consisted of tricolpate angiosperm pollen, bisaccate conifer pollen, monosulcate pollen, Corollina and minor representations of Liliacidites, trilete spores and taxodiaceous pollen (fig. 3). The 

high percentage of unidentified palynomorphs (averaging 32 percent of the assemblage) attests to the generally poor condition of the palynomorphs present. Figure 

3 includes counts of palynomorph types in four separate 

preparations. Modification of preparation procedures 

were tried in attempts to obtain better recovery from 

this sample. That some of the preparations were better 

than others is evident upon examination of the graph. 

For example, preparation C (D5758-B, prep. 2) yielded
PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

50-n

40 

30-

20 

10

Slides counted

A 05785(2) First preparation 

B D5785-A(2) Second preparation 

C D5785-B(2) Second preparation 

D D5785-A(1) Fourth preparation 

lii Average

A B C D 

Bisaccate 

pollen

A B C D 

Carol I in a

A B C D 

Tricolpate 

pollen

A B C D 

Monosulcate 

pollen

A B C D 

Trilete 

spores

A B C D 

Liliacidites

A B C D 

Taxodiaceaepollenites

A B C D 

Unidentified

FIGURE 3. Percentage distribution of major plant microfossil groups from several preparations of the productive Cedar Mountain sample.

only 6 percent bisaccate conifer pollen, and the unidentified palynomorphs accounted for 47 percent of the assemblage. In contrast, preparation A (D5758, prep. 1) 

yielded 21 percent bisaccate conifer pollen and only 19 

percent unidentified palynomorphs. Except for discrepancies accounted for by the varied preparation procedures, the recovery of the several palynomorph 

groups shows a remarkable consistency.

The following genera and species have been identified 

from the preparations, and the taxa are shown on plates

Laevigatosporites cf. L. belfordii Burger 1976 

Laevigatosporites gracilis Wilson and Webster 1946 

Cyathidites australis Couper 1953 

Todisporites sp.

Todisporites minor Couper 1958 

Gleicheniidites senonicus Ross 1949 

Lygodiumsporites sp. 

Deltoidospora hallii Miner 1935

Cyathidites minor Couper 1953

Dictyotriletes granulatus Pocock 1962

Foraminisporis sp.

Foraminisporis cf. F. wonthaggiensis (Cookson and

Dettman) Dettmann 1963 

Concavissimisporites variverrucatus (Couper) Singh

1964 

Concavissimisporites punctatus (Delcourt and

Sprumont) Brenner 1963 

Leptolepidites sp. 

Baculatisporites comaumensis (Cookson) Potonie

1956 

Pilosisporites trichopapillosus (Thiergart) Delcourt

& Sprumont 1955

Echinatisporis varispinosus (Pocock) Srivastava 1975 

Cicatricosisporites hughesii Dettmann 1963 

Cicatricosisporites sp. 

Cicatricosisporites cf. C. minutaestriatus (Bolkhovitina) Pocock 1964
LOCATION OF PRODUCTIVE SAMPLES

Cicatricosisporites venustus Deak 1963

Distaltriangulisporites cf. D. irregularis Singh 1971

Costatoperforosporites sp.

Psilatriletes circumundulatus Brenner 1963

Densoisporites microrugulatus Brenner 1963

Densoisporites velatus Weyland and Krieger 1953

cf. Schizosporis sp.

Alisporites grandis (Cookson) Dettmann 1963

Pityosporites granulatus Phillips and Felix 1971

Pityosporites nigraeformis (Bolkhovitina) Pocock

1970b

Pristinuspollenites sulcatus (Pierce) B. Tschudy 1973 

Cedripites cf. C. cretaceus Pocock 1962 

Cedripites canadensis Pocock 1962 

Podocarpidites multesimus (Bolkhovitina) Pocock

1962

Podocarpidites cf. P. minisculus Singh 1964 

Podocarpidites sp.

Vitreisporites pallidus (Reissinger) Nilsson 1958 

Cycadopites carpentieri (Delcourt and Sprumont)

Singh 1964

Monocolpopollenites sp. 

Ginkgocycadophytus cf. G. nitidus (Balme) de Jersey

1962

Equisetosporites multicostatus (Brenner) Norris 1967 

Taxodiaceaepollenites hiatus (Potonie) Kremp 1949 

Eucommiidites sp. 

Corollina torosa (Reissinger) Cornet and Traverse

1975

Exesipollenites tumulus Balme 1957 

Asteropollis asteroides Hedlund & Norris 1968 

Clavatipollenites hughesii (Couper) Kemp 1968 

Liliacidites sp.

Liliacidites cf. L. peroreticulatus (Brenner) Singh

1971 

Tricolpites crassimurus (Groot and Penny) Singh

1971 

Retitricolpites cf. R. virgeus (Groot, Penny and

Groot) Brenner 1963 

Retitricolpites vulgaris Pierce 1961

Retitricolpites vennimurus Brenner 1963 

Striatopollis paraneus (Norris) Singh 1971 

Rousea georgensis (Brenner) Dettman 1973 

Cupuliferoidaepollenites parvulus (Groot and Penny)

Dettmann 1973 

Cupuliferoidaepollenites minutus (Brenner) Singh

1971

Tricolpites cf. T. wilsonii Kimyai 1966 

Tricolpites cf. T. sp. 1 of Kemp (1968) 

Tricolpites micromunus (Groot and Penny) Singh

1971

Tetracolpites cf. T. pulcher Srivastava 1969 

Tetracolpites sp.

LANDMARK EVOLUTIONARY EVENTS IN THE 

DEVELOPMENT OF ANGIOSPERM POLLEN

The earliest records of angiosperm pollen include 

some of the same taxa that were recovered from the 

Cedar Mountain Formation. The first occurrences of angiosperm pollen in the stratigraphic record and the subsequent diversification of angiosperm pollen is pertinent 

to the age determinations and conclusions derived from 

Cedar Mountain samples.

The stratigraphic record has provided the basis for 

several outlines of the developmental history of angiosperm pollen, particularly in North America (Singh, 

1971, 1975; Doyle, 1969; Jarzen and Norris 1975; Norris, 

Jarzen, and Awai-Thorne, 1975; Muller, 1970; and 

others). These outlines present data concerning the earliest record of angiosperm pollen, followed successively 

by the first appearance of tricolpate pollen, tricolporate 

pollen, triporate pollen; and in the Cenomanian and 

later stages, the times of origin of evolutionarily more 

advanced pollen types.

There are no substantiated pre-Cretaceous records 

of angiosperm pollen. The most primitive putative angiosperm pollen type is a monosulcate grain with pilate 

or retipilate sculpture, represented by the genus 

Clavatipollenites Couper. Couper (1958), in describing 

the type species C. hughesii from the Barremian of 

England, pointed out that although the monosulcate 

aperture condition is prevalent in gymnosperms, pilate 

or retipilate sculpture is not known outside the angiosperms. Pollen grains of the Clavatipollenites type are 

now considered by the vast majority of palynologists 

to be of probable angiosperm origin. Clavatipollenites 

pollen has been widely reported in rocks of Aptian-Albian Age from diverse parts of the world: Hughes 

(1958) and Kemp (1968) from England, Couper (1964) 

from Central America and Australia, Kemp (1968) and 

Norris (1967) from western Canada, and Brenner (1963) 

from eastern United States. Chlonova (1977) reported 

the first find of Clavatipollenites in ?Albian-Cenomanian rocks of Western Siberia. She discussed the preBarremian (Jurassic) records of identifications of 

Clavatipollenites (from central Europe and Asia) and 

rejected them as not being completely reliable. Birkelund, and others (1978) and Vigran and Thusu (1975) 

reported Clavatipollenites from Jurassic and pre-Jurassic rocks of Norway. Perhaps significantly, Birkelund 

and others (1978) found Clavatipollenites in their assemblage 1 (Middle Jurassic) but not in younger assemblages assemblage 2 (Kimmeridgian), assemblage 

3 (Kimmeridgian-Volgian), and assemblage 4 (early 

Neocomian).

In North America, the oldest record of Clavatipollenites is from the upper part of the Barremian (Doyle, 

1969; Doyle and Robbins, 1977). In western Canada,
10 PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

the entrance level of Clavatipollenites coincides in Alberta with the entrance level of reticulate tricolpate 

forms (middle Albian). Clavatipollenites was not found 

in Canada in the Loon River Formation, lower mid-Albian (Singh, 1975), nor in the Mannville Group (Singh, 

1964; Norris, 1967) of Aptian to early middle Albian 

age and no older than late Barremian (Singh, 1964). 

Thus, in western North America there are no records 

of Clavatipollenites earlier than mid-Albian time. The 

presence of specimens of Clavatipollenites in Cedar 

Mountain rocks therefore suggests an Albian or 

younger age.

Tricolpate pollen first appears, apparently 

worldwide, in the Albian. "The appearance of tricolpate 

pollen seems to have been a major world-wide event, 

and in all areas which have been carefully studied there 

is a zone with small reticulate tricolpates but without 

triporates or typical tricolporates (cf. Krutzsch, 1963; 

Muller, 1968). This appearance generally may be dated 

as early or middle Albian, but refinement is needed 

in most areas." (Doyle, 1969, p. 11). Singh (1971, p. 

25) has summarized these data as follows: "The entrance of tricolpate dicotyledonous pollen in Albian 

strata of North America has been well documented by 

Brenner (1963), Davis (1963), Pannella (1966), Norris 

(1967), and Hedlund and Norris (1968). In other parts 

of the world, the first definite dicotyledonous pollen has 

been reported from Albian strata of central Russia (Bolkhovitina, 1953), New Zealand (Couper, 1960), Portugal 

(Groot and Groot, 1962), Central America and Africa 

(Couper, 1964), Peru (Brenner, 1968), Australia (Dettmann and Playford, 1968) and England (Kemp, 1968). 

Thus the entrance of tricolpate dicotyledonous pollen 

in the Lower Cretaceous succession of the Peace River 

area supports the middle to late Albian age assigned 

to these beds on faunal evidence (Wickenden, 1951, 

Stelck, etal., 1956)."

The angiosperm pollen succession in eastern Australia was discussed by Dettmann (1973). She reported 

that the earliest occurrence of tricolpate pollen was 

found in the middle Albian of the Great Artesian Basin, 

whereas tricolpate pollen first appears a little later, in 

the upper Albian, in the more southerly Otway Basin. 

The first occurrence of tricolpate angiosperm pollen in 

Australia appears to coincide in time with its first appearance in Western North American rocks.

Tricolporate pollen first appears in latest? Albian 

time in western Canada and western United States and 

in the early Cenomanian in eastern United States 

(Singh, 1975). Tricolporate pollen has a widespread distribution throughout the Cenomanian of the Western 

Interior. Singh (1975, p. 377) concluded "It is evident 

from the above discussion that the Albian-Cenomanian 

boundary in North America is marked by the appearance of smooth, triangular tricolporates (Table II, III) 

and angiosperm tetrads."

The tricolporate pollen mentioned by Singh (1975) is 

the species Nyssapollenites albertensis Singh. It appears just below the fish scale member in the Shaftesbury Formation of Alberta (uppermost Albian). The 

same species identified as Tricolporopollenites aliquantulus Hedlund was found in the Red Branch Member 

of the Woodbine Formation of Oklahoma (Cenomanian) 

(Hedlund, 1966). Pannella (1966) reported the same 

species (as Tricolporites dakotensis) from the upper 

part of the Dakota Sandstone and the Huntsman Shale 

of MacKenzie (1965) (upper Albian-Cenomanian) of the 

Denver basin, Colorado. The same species (as Tricolporopollenites aliquantulus Hedlund) was found in the 

Dakota Sandstone of Arizona (Cenomanian) by Agasie 

(1969). We have found pollen of Nyssapollenites albertensis Singh to be a common constituent of Cenomanian 

rocks of Colorado and Utah. In the Front Range near 

Denver, Colo., the entrance level of this species is in 

the middle part of the Kassler Sandstone Member of 

the South Platte Formation (Dakota Group) about 30.5 

m below the base of the Benton Formation (Mowry 

Shale to the north). The Mowry Shale is characterized 

by abundant fish scales, and is found at approximately 

the same stratigraphic position as the "fish scale marker 

bed" ("The traditional Lower-Upper Cretaceous boundary***" (Norris and others, 1975) in the Shaftesbury 

Formation of Alberta Canada. Significantly, Singh 

(1971, p. 28) found the entrance level of Nyssapollenites 

albertensis at about 35.0 m below the "fish scale marker 

bed." With the exceptions of the latest Albian report 

by Singh (1971) and the late Albian (Dakota) report 

by Pannella (1966), all other records of tricolporate pollen from western North America are from Cenomanian 

and younger rocks. The consistent first occurrence of 

Nyssapollenites albertensis at or very near the AlbianCenomanian boundary provides a reliable indicator in 

western North America of the palynological boundary 

between the Early and Late Cretaceous. This 

palynological marker species coincides with or is close 

to the Early-Late Cretaceous boundary based on other 

types of evidence.

AGE OF THE UPPER PART OF THE 

CEDAR MOUNTAIN FORMATION

The absence of any tricolporate pollen eliminates the 

possibility of a Cenomanian Age. The presence of small 

tricolpate pollen indicates an age range from middle to 

late Albian. The presence of at least 11 identified 

species of tricolpate pollen suggests that a significant 

amount of time must have elapsed since the origin of 

tricolpates in the mid Albian, until the plants had 

evolved to produce the diverse tricolpate flora including 

such large forms as Tetracolpites pulcher Srivastava.
PALYNOLOGICAL ANALYSIS BURRO CANYON FORMATION 11

Thus, this assemblage is clearly of late or latest Albian 

age.

PALYNOLOGICAL ANALYSIS BURRO 

CANYON FORMATION

The Burro Canyon Formation also has yielded few 

fossils. Fossil evidence for the age of the Burro Canyon 

Formation was presented by Stokes (1952) and Simmons (1957). The fossils were obtained from the 

NE1/4NW1/4NE1/4 sec. 11, T. 43 N., R. 18 W., San 

Miguel County, Colo. This locality is the identical locality that yielded palynomorphs from the upper Burro 

Canyon horizon mentioned previously. The following 

fossils of possible age significance were reported:

Plant Frenelopsis varians Fontaine (Aptian-early 

Albian)

Molluscs Protelliptio douglassi Stanton (Aptian) 

"Unw"farri Stanton (Aptian) 

Nipponaia asinaria Reeside (Early Cretaceous)

No other reports of fossils from the Burro Canyon Formation have come to our attention.

A second locality that yielded palynomorphs, about 

10.4 m below the base of the upper Burro Canyon horizon, has been mentioned previously. No other types 

of fossils are known from this second locality.

As with the Cedar Mountain Formation, the Burro 

Canyon Formation samples were examined palynologically in an attempt to obtain a more refined age determination, to address the question raised by reported 

intertonguing of the basal part of the Burro Canyon 

and upper part of the Morrison Formations (Simmons, 

1957, p. 2523), and to attempt to determine whether 

or not the Burro Canyon and Cedar Mountain Formations are correlative palynologically.

The overlying Dakota Sandstone in this area is 

palynologically of early Cenomanian age (it has yielded 

Nyssapollenites albertensis Singh). The Burro Canyon 

Formation lies between the Dakota and the Morrison. 

In some places, evidence exists of apparent continuous 

deposition from the Morrison into the basal part of the 

Burro Canyon. Samples obtained from the upper or 

Brushy Basin Member of the Morrison Formation in 

this general area have yielded a palynological suite of 

fossils indicative of a Late Jurassic age. Theoretically, 

the Burro Canyon Formation could represent an age 

ranging from Late Jurassic to Cenomanian that is, the 

entire Early Cretaceous spanning a time interval of 

some 40 million years.

UPPER HORIZON

As has been indicated, two palynologically productive 

horizons were found in the upper part of the Burro 

Canyon Formation. The upper horizon sample, from a

1.5-m-thick layer of black fissile shale about 7.3 m below 

the base of the Dakota Sandstone, yielded sparse assemblages of palynomorphs. The great majority of the 

organic matter consisted of what appeared to be short 

filaments (fig. 4A). On closer examination these filaments proved to be aggregates of amorphous material. 

At higher magnification, the apparent strands lose their 

continuity and appear as small strands with somewhat 

indefinite margins (fig. 4B). In the lower part of the 

photomicrograph (fig. 4B) a fragment of black woody 

tissue can be seen. Near the center a palynomorph is 

obscured by this organic material. At succeedingly 

higher magnifications (fig. 4C, D, and E scanning electron micrographs), the organic material exhibits its 

amorphous character, and the filamentous attribute effectively disappears. Contrast between upper-horizon 

preparations containing an abundance of amorphous organic material and more nearly normal preparations is 

shown on a photomicrograph of a preparation from the 

lower horizon (fig. 4P). Wood fragments, bits of epidermal and cuticular tissue, and easily recognizable 

palynomorphs are visible. This preparation is virtually 

devoid of organic material of the kind found in upper 

horizon samples. The great abundance of amorphous organic material present in upper horizon samples could 

not be removed from the samples by oxidation without 

destroying the accompanying palynomorphs. Thus, the 

few spores and pollen grains present were commonly 

obscured by this material. Samples from the upper horizon are unique in this respect in our experience. We 

have never found samples that reacted in the same 

manner. The closest observed similarity is to samples 

of oil shale from the Green River Formation, yet the 

organic material in the Green River oil shale appears 

visually to be distinctly different.

Two samples of black fissile shale from the upper 

horizon were submitted to L. G. Schultz, U. S. Geological Survey, Denver, Colo. for X-ray analysis. He reported that the nonorganic part of the black shale contained 2-10 percent calcite, 1 to 2 percent quartz, and 

a large percentage of mixed-layer illite-smectite, a 

swelling clay that could be an altered tuff.

Thin sections made from this upper horizon shale 

show the abundance and bedded nature of the unaltered 

organic material but give no hint of its original composition (fig. 5). These thin sections, plus macerated sample 

material from the upper horizon were sent to the late 

Dr. J. M. Schopf, USGS Coal Geology Laboratory at 

Columbus, Ohio. He remarked (written commun., Dec. 

13, 1977) "The thin sections are excellent ... I wish 

I could suggest how such a rock could reasonably be 

deposited. My next suggestion is that it must be an 

unusual local occurrence."

This abundant amorphous organic material possibly 

could be the residue from some, as yet unidentified,
12 PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

- ,

-, %

f

\J
PALYNOLOGICAL ANALYSIS BURRO CANYON FORMATION 13

""SM,- >-*fe .. ».^ * - t

FIGURE 5. Burro Canyon-upper horizon sample D5510-A. Thin section of whole rock showing bedded nature of organic material, 

x 100.

alga. Botryococcus, a common lacustrine alga, has been 

found in all upper horizon samples.

PALYNOMORPH RECOVERY FROM 

UPPER HORIZON SAMPLES

The palynomorph recovery from upper horizon samples was sparse. The abundant organic matter and the 

comparatively poor state of preservation made identification extremely difficult. Gross palynomorph recovery from representative upper horizon samples is shown 

in figure 6. The average number of unidentified forms 

was 48 percent, attesting to the difficulty posed by the 

amorphous organic material.

The following identified taxa were obtained from an 

examination of more than 60 slides.

Burro Canyon upper horizon

Undulatisporites cf. U. fossulatus Singh 1971

Cyathidites minor Couper 1953

Todisporites minor Couper 1958

Dictyotriletes pseudoreticulatus (Couper) Pocock

1962 

Cadargasporites reticulatus de Jersey and Paten

1964

Staplinisporites caminus (Balme) Pocock 1962

Matthesisporites tumulosus Boring 1964

aff. Cicatricosisporites phaseolus (Delcourt and

Sprumont) Krutzsch 1959 

Converrucosisporites cf. C. proxigranulatus Brenner

1963 

Cicatricosisporites cf. C. minor (Bolkhovitina)

Pocock 1964

Cicatricosisporites cf. C. cuneiformis Pocock 1964 

Cicatricosisporites augustus Singh 1971 

Cicatricosisporites cf. C. potomacensis Brenner 1963 

Cicatricosisporites cf. C. mediostriatus (Bolkhovitina) Pocock 1964 

Cicatricosisporites sp. 

Cicatricosisporites pseudotripartitus (Bolkhovitina)

Dettmann 1963

Cicatricosisporites apiteretus Phillips and Felix 1971 

Cicatricosisporites cf. C. subrotundus Brenner 1963 

Cicatricosisporites cf. C. crassistriatus Burger 1966 

Distaltriangulisporis sp. 

Appendicisporites bilateralis Singh 1971 

Appendicisporites jansonii Pocock 1962 

Corollina torosa (Reissinger) Cornet and Traverse

1975

Equisetosporites spp. 

Araucariacites sp. 

Callialasporites sp.

Vitreisporites pallidus (Reissinger) Nilsson 1958 

Alisporites thomasii (Couper) Pocock 1962 

Alisporites grandis (Cookson) Dettmann 1963 

Cedripites cf. C. canadensis Pocock 1962 

Cedripites cretaceus Pocock 1962 

Podocarpidites ornatus Pocock 1962 

Burro Canyon taxa are shown on plates 5-9.

LOWER HORIZON

This locality was found about 10.4 m below the upper 

fissile shale horizon. The recovery of palynomorphs was 

much better than from upper horizon samples even 

though preservation quality was not the best. The difference in appearance of the slides from the two horizons is shown on figure 4. In figure 4F fusainized wood 

fragments are prevalent in the photograph, and epidermal tissue and palynomorphs make up the lighter, more 

translucent material. The appearance of the organic material from the lower horizon is normal, in contrast to

FIGURE 4 (facing page). Burro Canyon-upper horizon sample. A, After HF treatment and flotation in ZnBr2 water mount, x 500. B, 

Standard treatment. Mounted in AYAF and histoclad. x 1000. Note wood fragment at center lower margin, and palynomorph at 

center, obscured by organic material. C, Electron micrograph x 5000. D, Electron micrograph x 16000. E, Electron micrograph x 

20,000. F, Lower horizon sample showing more normal appearance of material on slide; xlOO. Note epidermal tissue at upper left 

corner and several palynomorphs.
14

60 -|

PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

60

50 -

40 -

o 30 -

20 -

10 

Slides counted 

A D5786-B(2) 

B 05801(1) 

C D5510-C(1) 

p3 Average

ABC 

Bisaccate 

pollen

ABC 

Corollina

ABC 

Trilete 

spores

ABC 

Other

ABC 

Unidentified

FIGURE 6. Gross palynomorph recovery from some upper horizon 

Burro Canyon samples.

the appearance of the organic material from the upper 

horizon.

A comparison of the gross palynomorph recovery 

from the upper and lower horizons is shown in figure 

7. The contrast is shown vividly by the absence of unidentified forms from the lower horizon. The lower horizon assemblage is dominated by bisaccate conifer pollen 

and Corollina, The residue of palynomorphs makes up 

less than 3 percent of the total assemblage.

The first samples collected from the lower horizon 

showed a marked difference in recovery from hard

Upper horizon Lower horizon

m

FIGURE 7. Comparison of gross palynomorph recovery from Burro 

Canyon upper and lower horizons. Average recovery data for 

upper horizon taken from figure 5. Average recovery data from 

lower horizon taken from figure 8. Unidentified fossils may consist of Corollina, and possibly unidentified algae. Botryococctis 

is present in all samples but commonly is not abundant.

dark-gray shale and from black friable shale containing 

small calcite crystals. The hard dark-gray shale (interval C, fig. 8) was dominated by bisaccate conifer pollen 

and the black friable shale (interval D, fig. 8) by Corollina pollen. The lower horizon was therefore recollected 

the following year in an attempt to verify these data. 

The possibly productive interval consisted of 87 cm of
PALYNOLOGICAL ANALYSIS BURRO CANYON FORMATION 15

alternating shale, calcareous shale, and limestone capped by 40 cm of blocky gray limestone. Six samples 

were taken from the 87-cm interval as shown on figure 

8.

PALYNOMORPH RECOVERY FROM 

LOWER HORIZON SAMPLES

The upper two samples were barren. The gross 

palynomorph recovery of the four lower samples is 

shown in figure 8. The sample D5972-D yielded 97 percent bisaccate conifer pollen and only 1 percent Corollina, whereas samples D5972-C, D5972-B and D5972-A 

yielded 20, 23, and 35 percent bisaccate conifer pollen, 

respectively, and the assemblages were dominated by 

abundant Corollina specimens. Bisaccate pollen and 

pollen of Corollina were produced by conifers. Corollina pollen was produced by the fossil tree genus 

Cheirolepis. The prominent change in abundance of 

these two pollen groups in a comparatively short 

stratigraphic interval indicates a prominent floral 

change and suggests a prominent biofacies difference 

between the two groups of samples.

The following taxa were identified from the lower 

horizon:

Gleicheniidites senonicus- (Ross) Skarby 1964

Cyathidites minor Couper 1953

Deltoidospora cf. D. psilostoma Rouse 1959

Tigrisporites reticulatus Singh 1971

Interulobites triangularis (Brenner) Phillips and

Felix 1971

Staplinisporites caminus (Balme) Pocock 1962 

Lycopodiumsporites sp. 

Matthesisporites tumulosus Boring 1964 

Leptolepidites verrucatus Couper 1953 

Verrucosisporites cf. V. densus (Bolkhovitina) Pocock

1970a

Cicatricosisporites sp. 

Cicatricosisporites pseudotripartitus (Bolkhovitina)

Dettmann 1963

Distaltriangulisporis perplexus (Singh) Singh 1971 

Corollina torosa (Reissinger) Cornet and Traverse

1975

Cycadopites spp. 

Equisetosporites spp. 

Araucariacites sp. 

Exesipollenites tumulus Balme 1957 

Cerebropollenites mesozoicus (Couper) Nilsson 1958 

Callialasporites segmentatus (Balme) Sukh-Dev 1961 

Vitreisporites pallidus (Reissinger) Nilsson 1958 

Pristinuspollenites sulcatus (Pierce) B. Tschudy 1973 

Clavatipollenites hughesii (Couper) Kemp 1968 

Paleoconiferus asaccatus Bolkhovitina 1956

Pityosporites cf. P. divulgatus (Bolkhovitina) Pocock

1970b

Alisporites grandis (Cookson) Dettmann 1963 

Pityosporites nigraeformis (Bolkhovitina) Pocock

1970b

Cedripites cf. C. canadensis Pocock 1962 

Cedripites cretaceus Pocock 1962 

Podocarpidites ornatus Pocock 1962 

Podocarpidites cf. P. ellipticus Cookson 1947 

Podocarpidites cf. P. multesimus (Bolkhovitina)

Pocock 1962

Podocarpidites radiatus Brenner 1963 

Burro Canyon taxa are shown on plates 5-9

The chief distinction between the assemblages from 

the upper and lower horizons of the Burro Canyon is 

that many species and specimens of Cicatricosisporites 

were found in the upper horizon assemblages and very 

few Cicatricosisporites specimens were found in the 

lower horizon assemblages.

AGE OF THE UPPER PART OF THE 

BURRO CANYON FORMATION

Both upper and lower horizon assemblages were from 

the upper part of the Burro Canyon Formation, so for 

the purpose of this discussion they will be considered 

as a unit even though the discrepancies in recovery may 

appear significant. These discrepancies may be due in 

part to variations in biofacies existing at the times of 

deposition, giving rise to the distinctly different organic 

content of the two groups of samples. It may also be 

due, in part, to the low frequency of recovery of individual taxa. With the exception of bisaccate conifer pollen and Corollina, many of the remaining taxa were 

found only as single specimens, or generally as only 

a few specimens of any single taxon.

Bisaccate conifer pollen is difficult to segregate into 

generic units. Futhermore, most genera and species are 

long-ranging and are of little value in age determinations. Corollina pollen is almost omnipresent in Upper 

Jurassic and Lower Cretaceous continental 

palynomorph-bearing rocks of North America. Consequently the remaining taxa, even though present in 

extremely low frequency in the samples, are the significant taxa for the estimation of the ages of the samples.

The palynomorphs recovered failed to reveal even a 

single specimen of tricolpate pollen. The apparent first 

record of tricolpate (tricolporate) pollen is from the Berriasian-Valanginian of the Netherlands (Burger, 1966). 

But well-documented tricolpates first appear in the 

Aptian-Albian worldwide (Doyle, 1969; Muller, 1970; 

Chlonova, 1977). In North America, tricolpates enter 

the stratigraphic record no earlier than mid-Albian time
16 PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

97

Lithology Thickness, in 

centimeters

Limestone, grey, blocky 40

Shale, black, hard, calcareous

Limestone, black

Shale, black, hard, calcareous 14

Limestone, grey

Shale, dark-grey, hard

Thin bentonite layers are 

represented by dark bands

18

Shale, black, friable; small 

calcite crystals

Shale, grey to black, hard, 

calcareous

23

Shale, black- to green-weathering 

calcareous 12

Shale, green-weathering, calcareous

80

- 60

 40

- 20

- 0

TYPE OF PALYNOMORPH 

M Corollina ;X Trilete spores Other

FIGURE 8. Gross palynomorph recovery from selected intervals in lower horizon Burro Canyon. A-F, Intervals from which samples (D-numbers) were taken. Samples from intervals A and B were barren of palynomorphs. Numbers at top of bars indicate percentage of 

each type of palynomorph.

(Singh, 1975). Consequently, palynomorph assemblages 

lacking tricolpate pollen may be assumed to be no 

younger than mid-Albian.

Because of the purported interfingering of the Jurassic Brushy Basin Member of the Morrison with the 

lower part of the Burro Canyon Formation, comparisons of Burro Canyon assemblages with Jurassic and 

early Early Cretaceous assemblages were made. The

Burro Canyon palynomorph assemblages are distinctly 

more advanced than are Late Jurassic assemblages 

from the Colorado Plateau, or from Western Canada 

(Pocock, 1962; 1970a,b). For example, two species of 

Appendicisporites were isolated from the Burro Canyon 

Formation. This taxon is not present in the Jurassic; 

it first appears worldwide in the Valanginian (Pocock, 

1967; Vakhrameev and others, 1973). Further, many
PALYNOLOGICAL ANALYSIS-BURRO CANYON FORMATION 17

species of Cicatricosisporites are present in the Burro 

Canyon, and although a few species have been reported 

from the Upper Jurassic of Europe and Asia, none have 

been found in the Jurassic of western Canada (Pocock, 

1970a), nor have we found any specimens of Cicatricosisporites in any of the assemblages from the 

Brushy Basin, Westwater Canyon, or Recapture Members of the Morrison Formation (Upper Jurassic) of the 

Colorado Plateau region. Consequently, it is safe to assume that the age of the Burro Canyon Formation is 

Neocomian to early Albian.

Assemblages from near the Jurassic-Cretaceous 

boundary in northwest Europe (Boring, 1965; Burger, 

1966; Norris, 1969; Dorhofer and Norris, 1977; 

Dorhofer, 1977) were compared with those from the 

Burro Canyon Formation. Little similarity was evident. 

In fact, little similarity between assemblages of similar 

age from England and from continental northwest 

Europe was evident. "Of the 109 trilete spore types 

described by Boring (1965) from the German JurassicCretaceous sediments, only about 10 species are known 

in the southern England succession" (Norris, 1973, p. 

99). Furthermore, the assemblage from the German 

Biickeberg Formation (Dorhofer, 1977) (BerriasianValanginian) correlative with the English upper Purbeck and lower Wealden (Dorhofer and Norris, 1977) 

yielded no bisaccate conifer pollen. Most other Neocomian assemblages yielded significant proportions of 

bisaccate pollen. Consequently, the differing biofacies 

conditions in the two European localities and in the 

Burro Canyon Formation make comparisons more difficult.

The precise position of Lower Cretaceous samples 

cited in the literature is often not known. Reports refer 

in general terms to Lower Cretaceous, or to Neocomian 

rather than to the formal subdivisions. This usage is 

true of most reports from Australia and Russia. For 

example, Burger (1973) and Dettmann (1963) referred 

to the Lower Cretaceous or Neocomian, and OrlovaTurchina (1966) reported on the Hauterivian-Barremian 

Russian complexes in general terms only.

Another fact that hinders direct correlation is the 

yield of palynomorphs from the Burro Canyon Formation. The yield of taxa of potential usefulness was minimal. Aside from conifer pollen mostly long-ranging 

species and Corollina, the remainder of the assemblage 

as a whole was sparse (see fig. 6). Generally, only a 

few specimens of any one taxon were found. Many of 

the genera and species commonly used to subdivide the 

Neocomian in other regions failed to appear in Burro 

Canyon samples. These genera include Concavissimisporites, Trilobosporites, Impardecispora, Contignisporites, Januasporites, and Schizosporis.

Comparison of the Burro Canyon assemblages with

Jurassic and Early Cretaceous assemblages from western Canada failed to present evidence for direct correlation. This lack of evidence may be due to the fact that 

the Lower Cretaceous rocks of western Canada are 

commonly no older than Barremian (Singh, 1971). Only 

one report of upper Neocomian palynomorph assemblages from Canada is available. Hopkins (1971) reported an assemblage from the Isachsen Formation, 

bounded below by upper Valanginian rocks and above 

by Albian rocks. Hopkins (1971, p. 110) concluded that 

"The Isachsen Formation is therefore entirely Lower 

Cretaceous, ranging from Upper Valanginian, including 

probably Hauterivian and Barremian; possibly also Aptian***". Hopkins also observed "There appears to be 

no significant variation of the flora from the top to bottom of the Isachsen Formation suggesting that environmental conditions did not vary greatly during the time 

represented by Isachsen deposition, ***the flora is remarkably uniform over a comparatively long period of 

time (about 10 million years)." The palynomorph assemblage from the Isachsen Formation bears the 

closest resemblance to assemblages from the Burro 

Canyon Formation yet observed, even though most of 

the species mentioned did not appear in the Burro Canyon assemblages.

Adequate data are not yet available representing the 

age-ranges of taxa found in the Burro Canyon Formation owing to the comparatively few reliable reports 

on Lower Cretaceous rocks, particularly from North 

America. The currently known ranges of all species figured on plates 5-9 are recorded in table 2.

As shown on table 2, many of the identified species 

have long ranges, and offer no aid in narrowing down 

the age of the Burro Canyon Formation. Some of the 

other species, Verrucosisporites densus (Bolkhovitina) 

Pocock, Matthesisporites tumulosus Doring, Callialasporites segmentatus (Balme) Sukh-Dev, Paleoconiferus 

asaccatus Bolkhovitina, and Cadargasporites reticulatus de Jersey and Paten are limited, as understood at present, to the Jurassic. Cicatricosisporites 

apiteretus Phillips and Felix, is limited to the Cenomanian. The ranges of the Jurassic species in our samples 

possibly may be attributed to redeposition into Lower 

Cretaceous rocks, although no visual difference in the 

appearance of the fossils was observed. On the other 

hand, both the limited ranges of the Jurassic and 

Cenomanian species may be due to the limited amount 

of work that has been done on Lower Cretaceous rocks 

in North America. The true ranges may not yet be evident. For example, the genus Cadargasporites and the 

species Cadargasporites reticulatus de Jersey and 

Paten, have been reported previously, to our knowledge, only from the Early Jurassic of the Surat Basin, 

Australia (de Jersey and Paten, 1964). Yet the two
18 PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

TABLE 2. Stratigraphic ranges of Burro Canyon palynomorph species

atfiinhfini lrfl>P« sonnniVtis (Rr>R R ) SVarb"

JURASSIC

 

EARLY CRETACEOUS

NEOCOMIAN

BERRIASIAN

VALANGINIAN

HAUTERIVIAN

BARREMIAN APTIAN

?

ALBIAN

 

 

LATE

CRETACEOUS

specimens from the Burro Canyon Formation with their 

distinctive distal labyrinthine reticulum, and smooth 

proximal contact area, appear to be conspecific with the 

Australian species.

The data presented on table 2 suggest to us a late 

Neocomian to Aptian-Albian age. A few taxa from table 

2 merit further discussion.

Tigrisporites reticulatus Singh. This species was 

first reported by Singh (1971) from the middle Albian 

of Alberta, Canada. Its presently known range is from 

the mid-Albian to early Cenomanian. Although several 

specimens of this species were found, the species was

not represented in all preparations. This species is not 

as yet known from anywhere in the world except from 

western North America. A closely allied species, Tigrisporites scurrandus Morris with an almost identical 

known range (mid- and late Albian) also appears to be 

confined to western North America. We have found 

both species in formations of Albian Age from Colorado 

and Idaho.

Interulobites triangularis (Brenner) Phillips and 

Felix. This species was observed sporadically in Burro 

Canyon assemblages. It has been reported previously 

only by Brenner (1963) (as Lycopodiacidites trian-
PALYNOLOGICAL ANALYSIS BURRO CANYON FORMATION 19

gularis) from the Albian-Aptian, possibly Barremian, 

Patapsco, Arundel and Patuxent Formations of Maryland, by Phillips and Felix (1971) from the Albian 

Paluxy Formation of Louisiana, and by Scott (1976) 

from the Neocomian(?) Sundays River and Kirkwood 

Formations of South Africa.

Appendicisporites jansonii Pocock. The range of 

this species according to Singh (1971) is Barremian to 

Albian. Outside of Canada it has been reported by Hedlund and Morris (1968) from the -Albian of Oklahoma. 

Singh (1971) claimed that Appendicisporites sp. reported by Lantz (1958) from the Albian of England is 

conspecific with A. jansonii Pocock. The presence of 

Appendicisporites species suggests that the age of the 

Burro Canyon samples can be no older than Valanginian. "It is important to note the appearance, in the Valanginian of the genus Appendicisporites also. This 

genus is unknown in older deposits of Europe and 

Asia." (Vakrameev and others, 1973 p. 214). "No 

species of this genus have been recorded from strata 

older than this [Valanginian] anywhere in the world." 

(Pocock, 1967 p. 135).

Clavatipollenites hughesii (Couper) Kemp. A single 

specimen of Clavatipollenites hughesii (Couper) Kemp 

was found on one of the slides of a sample from the 

lower horizon. Although literature reports of Triassic 

and Jurassic occurrences from several parts of the 

world have appeared (see previous discussion), this 

species has not been reported from North American 

rocks older than Barremian and from western North 

American rocks older than Albian (Singh, 1975). Its earlier appearance elsewhere may mean that the parent 

plant had not migrated to North America earlier, or 

palynological investigations have not yet uncovered the 

data. The plant may have existed for a long time in 

extremely low frequency and in limited ecological environments, before it expanded its habitat and abundance 

sufficiently to be represented commonly in Albian and 

younger rocks.

The taxa discussed, combined with the absence of 

tricolpate pollen all point to an Aptian-early Albian age, 

with the remote possiblity of a late Barremian age, for 

the upper part of the Burro Canyon Formation.

CONCLUSIONS

Although all students of these beds are agreed that 

Burro Canyon and Cedar Mountain beds are physically 

continuous in large part, the results of the present 

study of palynomorphs shows a difference in age: the 

upper part of the Cedar Mountain is younger (late or 

latest Albian) than the upper part of the Burro Canyon 

(Aptian to early Albian and perhaps as old as Barremian). We suggest that the thick lower part of the 

Cedar Mountain, which is undated by fossils, may contain beds that are age equivalent to the older Burro 

Canyon beds. The beds equivalent to the uppermost 

Cedar Mountain beds of late or latest Albian age may 

have been removed by pre-Dakota (pre-earliest Late 

Cretaceous) erosion at the Burro Canyon locality or are 

represented in the 6 m of green mudstones (nonproductive of palynomorphs) at the top of the Burro Canyon 

at the collection locality. A further speculation that may 

be warranted is that the Neocomian (early Early Cretaceous) may be represented in a still-undated lower part 

of the Burro Canyon and Cedar Mountain perhaps 

even including an upper part of the Brushy Basin Member of the Morrison. The recognition of a fossil 

(Clavatipollenites hughesii (Couper) Kemp) known to 

occur as early as the Barremian (latest Neocomian) 

suggests that the undated older beds of these formations might contain beds of this age, a stage that is 

almost unrecorded in western North America.

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20 PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

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PALYNOLOGICAL ANALYSIS BURRO CANYON FORMATION 21

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INDEX

Page

Age ............................................... 1, 7, 10, 11, 19

albertensis, Nyssapollenites ............................ 10, 11

Algae ................................................................ 13

Alisporites grandis ..................... 9, 12, 15; pis. 3, 8

thomasii ............................................ 13; pi. 8

aliquantulus, Tricolporopollenites ........................ 10

apiteretus, Cicatricosisporites ..................... 13; pi. 6

Appendicisporites bilateralis ....................... 13; pi. 6

jansonii ........................................ 13, 19; pi. 6

sp. ......................................................... 16, 19

Araucariacites sp. ............................... 13, 15; pi. 7

Arundel Formation of Maryland .......................... 19

asaccatus, Paleoconiferus ....................... 15, 17; pi.8

asinaria, Nipponaia ........................................... 11

Aspen Shale ........................................................ 7

asteroides, Asteropollis ................................ 9; pi. 4

Asteropollis asteroides ................................. 9; pi. 4

augustus, Cicatricosisporites ...................... 13; pi. 6

australis, Cyathidites .................................. 8; pi. 1

B

Baculatisporites comaumensis ...................... 8; pi. 1

belfordii, Laevigatosporites ........................... 8; pi. 1

Benton Formation .............................................. 10

bilateralis, Appendicisporites ...................... 13; pi. 6

Botryococcus ...................................................... 13

Brushy Basin Member of the Morrison

Formation ...... 1, 11, 16, 17

Buckeberg Formation ......................................... 17

Buckhorn Conglomerate Member ........................... 2

Cadargasporites ...............................................

reticulatus ..................................... 13, 17;

Calcite ............................................................

Callialasporites segmentatus ................. 15, 17;

sp. ..................................................... 13;

canadensis, Cedripites ................ 9, 13, 15; pis.

carpentieri, Cycadopites ..........................

Castle Dale, Utah ............................................

Cedripites canadensis ................. 9, 13, 15; pis.

cretaceus ............................. 9, 13, 15; pis.

Cerebropollenites mesozoicus ...................... 15;

Charophyte ......................................................

Cheirolepis ......................................................

Cicatricosisporites apiteretus ................. 13, 17;

augustus ............................................ 13;

crassistriatus ...................................... 13;

cuneiformis ........................................ 13;

hughesii ............................................... 8;

mediastriatus ...................................... 13;

minor ............................................. 13;

minutaestriatus ..................................... 8;

phaseolus ........................................... 13;

potomacensis ...................................... 13;

pseudotripartitus ............................ 13, 15;

subrotundas ......................................... 13;

venustus ............................................... 9;

sp. ................................ 8, 13, 15, 17; pis.

circumundulatus, Psilatriletes ...................... 9;

Clavatipollenites hughesii............ 9, 15, 19; pis.

sp. ............................................................

Clavator harrisi ...............................................

Cloverly Formation ..........................................

comaumensis, Baculatisporites ..................... 8;

Concavissimisporites .........................................

pwnctatus ............................................. 8;

variverrucatus ....................................... 8;

.. 17

pi. 5

.. 11

pi. 7

pi. 7

3, 8

'; pi-4

..... 7

3, 8

3, 8

pi. 7

.... 7

.. 15

pi. 6

pi. 6

pi. 6

pi. 6

pi. 2

pi. 6

pi. 6

pi. 2

pi. 5

pi. 6

pi. 6

pi 6

pi. 2

2, 6

pi. 2

4, 7

.... 9

.... 7

4, 7

pi. 1

.. 17

pi. 1

pi. 1

Contignisporites ................................................. 17

Converrucosisporites proxigranulatus .......... 13; pi. 5

Corollina ............................................ 7, 14, 15, 17

torosa ................................. 9, 13, 15; pis. 4, 7

Costatoperforosporitessp. .............................. 9; pi. 2

Cottonwood Creek ................................................ 6

crassimurus, Tricolpites .............................. 9; pi. 4

crassistriatus, Cicatricosisporites ................ 13; pi. 6

cretaceus, Cedripites ................... 9, 13, 15; pis. 3, 8

cuminus, Staplitiisporites ...................... 13, 15; pi. 5

cuneiformis, Cicatricosisporites ................... 13; pi. 6

Cupwliferoidaepollenites minutus .................. 9; pi. 4

parvulus .............................................. 9; pi. 4

Cyathidites australis ................................... 8; pi. 1

minor ................................. 8, 13, 15; pis. 1, 5

Cycadopites carpentieri ................................ 9; pi. 4

spp. .............................................. 15; pis. 4, 7

D

Dakota Group ................................................ 4, 10

Dakota Sandstone ..................................... 1, 10, 11

dakotensis, Tricoloporites .................................... 10

Deltoidpspora hallii ..................................... 8; pi. 1

psilostoma .......................................... 15; pi. 5

Densoisporites micronigulatus ...................... 9; pi. 2

velatus ................................................. 9; pi. 2

densus, Verrucosisporites ...................... 15, 17; pi. 5

Dictyotriletes granulatus .............................. 8; pi. 1

pseudoreticulatus ................................. 13; pi. 5

Disappointment Creek ...................................... , 6

Distaltriangulisporites irregularis ................. 9; pi. 2

perplexus ........................................... 15; pi. 6

sp. .......................................................... 13; pi. 6

Distribution ......................................................... 4

divulgatus, Pityosporites ............................ 15; pi. 8

douglassi, Protelliptio ......................................... 11

E

Echinatisporis varispinosus .......................... 8; pi. 2

ellipticus, Podocarpidites ........................... 15; pi. 9

Equisetosporites spp. .......................... 13, 15; pi. 7

Eucommiidites sp. ..................................... 9; pi. 4

Eupera onestae .................................................... 7

Exesipollenites tumulus .................... 9, 15; pis. 4, 7

farri, "Unio" ..................................................... 11

Ferron, Utah ....................................................... 7

Foraminisporis wonthaggiensis ..................... 8; pi. 1

sp. ....................................................... 8; pi. 1

fossulatus, Undulatisporites ................................ 13

Four Corners ...................................................... 4

Frenelopsis varians ............................................ 11

Gannett Group ..................................................... 7

georgensis, Rousea ...................................... 9; pi. 4

Ginkgocycadophytus nitidus ......................... 9; pi. 4

Gleicheniidites senonicus ................... 8, 15; pis. 1, 5

gracilis, Laevigatosporites ............................ 8; pi. 1

grandis, Alisporites .................... 9, 13, 15; pis. 3, 8

granulatus, Dictyotriletes ............................. 8; pi. 1

Pityosporites ......................................... 9; pi. 3

Great Artesian Basin ......................................... 10

Green River Formation ...................................... 11

hallii, Deltoidospora .................................... 8; pi. 1

Hamm Canyon quadrangle ................................ 6, 7

harrisi, Clavator ................................................ 7

Henry Mountains ................................................. 4

hiatus, Taxodiaceaepollenites ........................ 9; pi. 4

hughesii, Cicatricosisporites ......................... 8; pi. 2

Clavatipollenites ......................... 9, 15, 19; pis. 4, 7

Huntsman Shale ................................................. 10

I

Icacinoxylon ........................................................ 7

Illite-smeetite ..................................................... 11

Impardecispora .................................................. 17

Interulobites triangularis ...................... 15, 18; pi. 5

irregularis, Distaltriangulisporites .............. 9; pi. 2

Isaehsen Formation ............................................ 17

J, K

jansonii, Appendicisporites ................. 13, 19; pi. 6

Januasporites .................................................... 17

Kassler Sandstone Member of the South Platte

Formation ..................... 10

Kirkwood Formation of South Africa ................... 19

Kootenai Formation .............................................. 7

Laevigatosporites belfordii ............................ 8

gracilis ................................................ 8

Leptolepidites verrucatus ............................ 15

sp. ....................................................... 8

Liliacidites ................................................

peroreticulatus ...................................... 9

sp. ....................................................... 9

Loon River Formation ...................................

pi. 1

pi. 1

pi. 5

pi. 1

..... 1

pi. 4

pi. 4

... 10

Lycopodiacidites triangularis ............................... 18

Lycopodiumsporitessp. ...................... 8, 15; pis. 1, 5

Lytle Formation of Dakota Group ......................... 4

Lytle Sandstone Member of Purgatoire Formation .. 4

M

Mannville Group ................................................ 10

Mattesisporites tumulosus ............... 13, 15, 17; pi. 5

mediostriatus, Cicatricosisporites ................ 13; pi. 6

mesozoicus, Cerebropollenites ..................... 15; pi. 7

micromunus, Tricolpites .............................. 9; pi. 4

microrugulatus, Densoisporites ..................... 9; pi. 2

minisculus, Podocarpidites ........................... 9; pi. 3

minor, Cicatricosisporites .......................... 13; pi. 6

Cyathidites .......................... 8, 13, 15; pis. 1, 5

Tempskya ...................................................... 1

Todisporites ............................... 8, 13; pis. 1, 5

minutaestriatus, Cicatricosisporites ............... 8; pi. 2

minutus, Cupuliferoidaepollenites ................. 9; pi. 4

Monocolpopollenitessp. ................................. 9; pi. 4

Morrison Formation ............................. 1, 11, 16, 17

Mowry Shale ..................................................... 10

multesimus, Podocarpidites ............... 9, 15; pis. 3, 9

multicostatus, Equisetosporites ..................... 9; pi. 4

N, 0

nigraeformis, Pityosporites ................ 9, 15; pis. 3, 8

Nipponaia asinaria ............................................ 11

nitidus, Ginkgocycadophytus ........................ 9; pi. 4

Nyssapollenites albertensis ............................. 10, 11

23
24 PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

Page 

onestae, Eupera ................................................... 7

ornatm, Podocarpidites ........................ 13, 15; pi. 9

Otway Basin ...................................................... 10

Paleoconiferus asaccatus .........:............. 15, 17;

pallidus, Vitreisporites ............... 9, 13, 15; pis.

Paluxy Formation of Louisiana .........................

paraneus, Striatopollis ................................ 9;

Paraphyllanthoxylon ........................................

parvulus, Cupuliferoidaepollenites ................ 9;

Patapsco Formation of Maryland .......................

Patuxent Formation of Maryland .......................

Peace River ....................................................

peroreticulatus, Liliacidites .......................... 9;

perplexus, Distaltriangulisporites ................ 15;

pkaseolus, Cicatricosisporites ..................... 13;

Pilosisporites trichopapillosus ....................... 8;

Pityosporites divulgatus ............................. 15;

granulatus ............................................ 9;

nigraeformis .............................. 9, 15; pis.

Podocarpidites ellipticus ............................ 15;

minisculus ........................................... 9;

multisimus ................................ 9, 15; pis.

ornatus ......................................... 13, 15;

radiatus ............................................. 15;

sp. ....................................................... 9;

potomacensis, Cicatricosisporites ................. 13;

Pristinuspollenites sulcatus ............... 9, 15; pis.

Protelliptio douglassi ........................................

proxigranulatus, Converrucosisporites ......... 13;

pseudoreticulatus, Dictyotriletes .................. 13;

pseudotripartitus, Cicatricosisporites ...... 13, 15;

Psilatriletes circumundulatus ....................... 9;

psilostoma, Deltoidospora .......................... 15;

pulcher, Tetracolpites ............................ 9, 10;

punctatus, Concavissimisporites .................... 8;

Purbeck Formation ...........................................

Purgatoire Formation .......................................

pi. 8

3, 7 

.. 19 

pi. 4 

.... 7 

pi. 4 

.. 19 

.. 19 

.. 10 

pi. 4 

pi. 6 

pi. 5 

pi. 2 

pi. 8 

pi. 3

3, 8 

pi. 9 

pi. 3

3, 9 

pi. 9 

pi. 9 

pi. 3 

pi. 6

3, 7 

.. 11 

pi. 5 

pi. 5 

pi. 6 

pi. 2 

pi. 5 

pi. 4 

pi. 1 

.. 17 

.... 4

Q,R

Quartz .............................................................. 11

radiatus, Podocarpidites ............................ 15; pi. 9

Racapture Member of the Morrison Formation ..... 17

Red Branch Member of the Woodbine Formation . 10 

reticulatus, Cadargasporites ................... 13, 7; pi. 5

Tigrisporites .................................. 15, 18; pi. 5

Retitricolpites vermimurus ........................... 9; pi- 4

virgeus ................................................. 9; pi. 4

vulgaris ............................................... 9; pi. 4

Rock Canyon Creek ............................................. 6

Rousea georgensis ....................................... 9; pi. 4

S

Sampling methods ................................................ 4

Schizosporis ....................................................... 17

sp. ....................................................... 9; pi. 2

scurrandus, Tigrisporites .................................... 18

segmentatus, Callialasporites ................ 15, 17; pi. 7

senonicus, Gleicheniidites .................. 8, 15; pis. 1, 5

Shaftesbury Formation of Alberta ....................... 10

Slick Rock, Colo. ................................................. 6

South Platte Formation ...................................... 10

Staplinisporites caminus ....................... 13, 15; pi. 5

Stokes-Katich locality ....................................... 6, 7

Striatopollis paraneus ................................. 9; pi. 4

subrotundas, Cicatricosisporites .................. 13; pi. 6

sulcatus, Pristinuspollenites .............. 9, 15; pis. 3, 7

Sundays River Formation of South Africa ........... 19

Surat Basin, Australia ........................................ 17

Taxodiaceaepollenites hiatus ......................... 9; pi. 4

Tempskya minor .................................................. 7

Tetracolpites pulcher ............................. 9, 10; pi. 4

sp. ....................................................... 9; pl. 4

thomasii, Alisporites ................................. 13; pl. 8

Tigrisporites reticulatus ........................ 15; 18; pl. 5

scurrandus .................................................. 18

Todisporites minor ........................... 8, 13; pis. 1, 5

sp. ....................................................... 8; pl. 1

torosa, Corollina ....................... 9, 13, 15; pis. 4, 7

triangularis, Interulobites ..................... 15, 18; pl. 5

Lycopodiacidites ................................................. 19

trichopapillosus, Pilosisporites ...................... 8; pl. 2

Tricolpites crassimurus ............................... 9; pl. 4

micromunus ............................................... 9; pl. 4

urilsonii ................................................ 9; pl. 4

sp. 1 ................................................... 9; pl. 4

Tricolporites dakotensis ...................................... 10

Tricolporopollenites aliquantulus ......................... 10

Trilobosporites ................................................... 17

Trinity Group of the Gulf Coast ........................... 7

tumulosus, Matthesisporites ............ 13, 15, 17; pl. 5

tumulus, Exesipollenites ................... 9, 15; pis. 4, 7

U, V, W

Undulatisporites fossulatus ........................ 13; pl. 5

"Unio" farri ...................................................... 11

varians, Frenelopsis ........................................... 11

varispinosus, Echinatisporis ......................... 8; pl. 2

varivermcatus, Concavissimisporites ............. 8; pl. 1

velatus, Densoisporites ................................ 9; pl. 2

venustus, Cicatricosisporites ......................... 9; pl. 2

vermimurus, Retitricolpites .......................... 9; pl. 4

verrucatus, Leptolepidites ........................... 15; pl. 5

Verrucosisporites densus ....................... 15, 17; pl. 5

virgeus, Retitricolpites ................................. 9; pl. 4

Vitreisporites pallidus ................ 9, 13, 15; pis. 3, 7

vulgaris, Retitricolpites ................................ 9; pl. 4

Wealden Formation ............................................ 17

Westwater Canyon Member of the Morrison

Formation ..................... 17

wonthaggiensis, Foraminisporis .................... 8; pl. 1

Woodbine Formation of Oklahoma ....................... 10

U.S GOVERNMENT PRINTING OFFICE: 1984 776-041/4024 REGION NO 8
PLATES 1-9
PLATE 1 

Cedar Mountain Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers (text fig. 2)]

FIGURE 1. Laevigatosporites cf. L. belfordii Burger 1976

Sample D5785-A, prep. 4, floated first, fines, slide 3, coordinates 99.0x21.6.

2. Laemgatosporites gracilis Wilson and Webster 1946 

Sample D5785, slide 1, coordinates 81.Ox 13.7.

3. Cyathidites australis Couper 1953

Sample D5785-A, prep. 4, floated first, hvs, slide 5, coordinates 112.5x8.2.

4. Todisporites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 89.3x 14.8.

5. Todisporites minor Couper 1958

Sample D5785-A, prep. 4, floated first, fines, slide 3, coordinates 106.2x6.7.

6. Gleicfieniidites senonicus Ross 1949

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 100.8x17.3.

7. Lygodiumsporites sp.

Sample D5785, slide 2, coordinates 76.7x10.1.

8. Deltoidospora hallii Miner 1935

Sample D5785-A, prep. 2, slide 1, coordinates 91.6x6.0.

9. Cyathidites minor Couper 1953

Sample D5785-A, prep. 4, floated first, fines, slide 3, coordinates 101.6x2.0.

10. Concavissimisporites variverrucatus (Couper) Singh 1964

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 110.2x18.4.

11. Foraminisporis sp.

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 96.8x6.7.

12. Concavissimisporites variverrucatus (Couper) Singh 1964

Sample D5785-A, prep. 4, floated first, hvs, slide 6, coordinates 112.5x8.2.

13. Dictyotriletes granulatus Pocock 1962

Sample D5785-A, prep. 4, floated first, fines, slide 1, coordinates 97.4x21.1.

14. Foraminisporis cf. F. wonthaggiensis (Cookson and Dettmann) Dettmann 1963 

Sample D5785-A, prep. 2, slide 1, coordinates 112.1x19.8.

15. Concavissimisporites punctatus (Delcourt and Sprumont) Brenner 1963

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 81.9x3.1.

16. Trilete spore undetermined.

Sample D5785-A, prep. 2, slide 1, coordinates 104.2x10.4. Ornamented with short blunt verrucae as well as short spines.

17. Leptolepidites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 87.6x5.1.

18. Baculatisporites comaumensis (Cookson) Potonie 1956

Sample D5785-A, prep. 2, slide 1, coordinates 110.5x11.1.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 1

V ' 18

LAEVIGATOSPORITES, CYATHIDITES, TODISPORITES. GLEICHENIIDITES. LYGODIUMSPORITES, 

DELTOIDOSPORA, CONCAVISSIMISPORITES, FORAMINISPORIS, TRILETE SPORE, 

LEPTOLEPIDITES, AND BACULATISPORITES
PLATE 2 

Cedar Mountain Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers (text fig. 2)]

FIGURE 1. Pilosisporites trichopapillosus (Thiergart) Delcourt and Sprumont 1955

Sample D5785-A, prep. 4, floated first, fines, slide 1, coordinates 77.7x5.4. 

2-4. Echinatisporis varispinosus (Pocock) Srivastava 1975

2. Sample D5785-A, prep.4, floated first, fines, slide 2, coordinates 87.3x5.9.

3. Sample D5785-A, prep. 4, floated first, fines, slide 3, coordinates 73.9x13.0.

4. Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 107.6x4.8.

5. Cicatricosisporites hughesii Dettmann 1963

Sample D5785-A, prep. 4, floated first, fines, slide 3, coordinates 108.4x13.3.

6. Cicatricosisporites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 74.0x7.5.

7. Cicatricosisporites cf. C. minutaestriatus (Bolkhovitina) Pocock 1964.

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 98.6x9.9.

8. Cicatricosisporites venustus Deak 1963

Sample D5785-A, prep. 2, slide 1, coordinates 110.0x6.2.

9. Cicatricosisporites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 95.1x21.1.

10. Distaltriangulisporites cf. D. irregularis Singh 1971

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 88,0x14.5.

11. Costatoperforosporites sp.

Sample D5785-A, prep. 4, hvs., slide 6, coordinates 76.8x8.0.

12. Trilete spore, undetermined.

Sample D5785, slide 2, coordinates 91.1x19.3.

13. Densoisporites microrugulatus Brenner 1963

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 75.^x8.0.

14. Psilatriletes circumundulatus Brenner 1963

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 84.2x20.4. 

15-16. Trilete spore, undetermined.

Sample D5785-A, prep. 2, slide 1, coordinates 90.5x19.4.

15. Proximal view.

16. Distal view.

17. Densoisporites velatus Weyland and Krieger 1953

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 83.5x12.4.

18. Undetermined.

Sample D5785-A, prep. 2, slide 1, coordinates 102.9x15.6.

19. cf. Schizosporis sp.

Sample D5785-A, prep. 4, floated first, fines, slide 1, coordinates 103.5x16.2
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 2

PILOSISPORITES, ECHINATISPORIS. CICATRICOSISPORITES, DISTALTRIANGULISPORITES. 

COSTATOPERFOROSPORITES, DENSOISPORITES, PSILATRILETES, cf. SCHIZOSPORIS,AND TRILETE SPORE
PLATE 3 

Cedar Mountain Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers (text fig. 2)]

FIGURE 1. Alisporites grandis (Cookson) Dettmann 1963

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 88.2x4.0.

2. Pityosporites granulatus Phillips and Felix 1971

Sample D5785-A, prep. 4, floated first, hvs., slide 5, coordinates 95.2x17.6.

3. Cedripites cf. C. cretaceus Pocock 1962

Sample D5785-A, prep. 4, floated first, fines, slide 1, coordinates 77.8x5.2.

4. Podocarpidites multesimus (Bolkhovitina) Pocock 1962

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 97.1x10.1.

5. Pityosporites nigraeformis (Bolkhovitina) Pocock 1970

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 83.2x22.3.

6. Pristimt^pollenites sulcatus (Pierce) B. Tschudy 1973

Sample D5785-A, prep. 4, floated first, fines, slide 1, coordinates 104.8x4.1.

7. Cedripites canadensis Pocock 1962

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 87.7x5.4.

8. Podocarpidites cf. P. minisculus Singh 1964

Sample D5785-A, prep. *, floated first, hvs., slide 5, coordinates 99.1x19.4.

9. Podocarpidites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 112.2x2.4.

10. Cedripites cf. C. canadensis Pocock 1962

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 74.8x11.9.

11. Vitreisporites pallidus (Reissinger) Nilsson 1958

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 110.3x18.0.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 3

8 -*m^ ^*ajft£:' 9

ALISPORITES, PITYOSPORITES, CEDRIPITES, PODOCARPIDITES, PRISTINUSPOLLENITES,

AND VITREISPORITES
PLATE 4 

Cedar Mountain Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany location numbers (text fig. 2)]

FIGURE 1. Cycadopites carpentieri (Del court and Sprumont) Singh 1964

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 110.9x12.1.

2. Cycadopites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 99.0x13.0.

3. Monocolpopollenites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 96.0x4.0.

4. Monocolpopollenites sp.

Sample D5785-B, slide 3, coordinates 101.6x14.2.

5. Ginkgocycadophytus cf. G. nitidus (Balme) de Jersey 1962

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 81.4x4.6.

6. Equisetosporites multicostatus (Brenner) Norris 1967 

Sample D5785-A, prep. 2, coordinates 106.1x22.5.

7. Taxodiaceaepollenites hiatus (Potonie) Kremp 1949.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 92.8x1.6.

8. Eucommiidites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 102.7x21.5.

9. Corollina torosa (Reissinger) Cornet and Traverse 1975.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 80.7x5.7.

10. Exesipollenites tumulus Balme 1957

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 78.3x2.1. 

11-12. Asteropollis asteroides Hedlund & Norris 1968

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 104.4x9.4.

11. Low focus showing baculae near equator.

12. High focus.

13. Clavatipollenites hughesii (Couper) Kemp 1968

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 112.0x21.0.

The size of this specimen is on the borderline between C. hughesii (Couper) Kemp and C. minutus Brenner.

14. Liliacidites sp.

Sample D5785-B, prep. 2, slide 2, coordinates 112.3x14.5.

15. Liliacidites cf. L. peroreticulatus (Brenner) Singh 1971 

Sample D5785-B, slide 3, coordinates 106.5x5.7.

16. Tricolpites crassimurus (Groot and Penny) Singh 1971

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 94.1x7.5.

17. Tricolpites cf. T. crassimurus (Groot and Penny) Singh 1971

Sample D5785-A, prep. 4, floated first, Hvs., slide 5, coordinates 88.2x9.1.

18. Cupuliferoidaepollenites parvulus (Groot and Penny) Dettmann 1973

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 90.5x2.1.

19. Retitricolpites cf. R. virgeus (Groot, Penny and Groot) Brenner 1963

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 83.0x11.8.

20. Retitricolpites vulgaris Pierce 1961

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 104.3x20.0.

21. Retitricolpites vulgaris Pierce 1961

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 111.4x17.0.

22. Tricolpites cf. T. mlsonii Kimyai 1966

Sample 5785-A, prep. 4, floated first, fines, slide 4, coordinates 88.0x16.2.

23. Striatopollis paraneus (Norris) Singh 1971

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 106.4x5.4.

24. Striatopollis paraneus (Norris) Singh 1971

Sample D5785, slide 2, coordinates 105.5x13.3.

25. Retitricolpites vermimurus Brenner 1963

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 97.5x19.8.

26. Rousea georgensis (Brenner) Dettman 1973

Sample D5785-A, prep. 4, floated first, Hvs., slide 5, coordinates 112.1x11.0.

27. Cupuliferoidaepollenites minutus (Brenner) Singh 1971

Sample D5785-B, prep. 2, slide 2, coordinates 111.5x8.6.

28. Tricolpites cf. T. sp. 1 of Kemp 1968

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 104.1x14.5 

29-30. Tricolpites micromunus (Groot and Penny) Singh 1971

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 110.7x2.0. (Sensu Groot and Penny. This specimen is 

small and may not be the same species as figured by Singh 1971).

29. High focus.

30. Low focus.

31. Tetracolpites cf. T. pulcher Srivasteva 1969

Sample D5785-A, prep. 4, floated first, fines, slide 3, coordinates 105.5x8.0.

32. Tetracolpites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 89.8x17.9.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 4

20

-*/' »'4 mi &!;&/'

21

rt^ fe\i

28

27

fp^5^£'29

B' 1<^M

HfeW 30 31

24

32

CYCADOPITES, MONOCOLPOPOLLENITES, GINKGOCYCADOPHYTUS, EQUISETOSPORITES,

TAXODIACEAEPOLLENITES, EUCOMMIIDITES, COROLLINA, EXESIPOLLENITES, ASTEROPOLLIS,

CLAVATIPOLLENITES, LILIACIDITES, TRICOLPITES, CUPULIFEROIDAEPOLLENITES,

RETITRICOLPITES, STRIATOPOLLIS, ROUSE A, AND TETRACOLPITES
PLATE 5 

Burro Canyon Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers, (text fig. 2)]

FIGURE 1. Gleicheniidites senonicus Ross 1949

Sample D5803, slide 22, coordinates 111.6x13.8.

2. Undulatisporites cf. U. fossulatus Singh 1971

Sample D5510-B, slide 1, coordinates 103.6x10.5.

3. Cyathidites minor Couper 1953

Sample D5510-C, slide 4, coordinates 105.9x6.8.

4. Deltoidospora cf. D. psilostoma Rouse 1959

Sample D5803, slide 12, coordinates 91.0x17.8.

5. Todisporites minor Couper 1958

Sample D5801, prep. 2, slide 4, coordinates 78.1x20.9.

6. Dictyotriletes pseudoreticulatus (Couper) Pocock 1962

Sample D5801, slide 2, coordinates 107.2x9.8. 

7-8. Tigrisporites reticulatus Singh 1971

Sample D5973, slide 2, coordinates 75.2x14.3. 

9-10. Cadargasporites reticulatus de Jersey and Paten 1964 

Sample D5510-B, slide 2, coordinates 93.8x3.0.

11. Interulobites triangularis (Brenner) Phillips and Felix 1971 

Sample D5803, slide 4, coordinates 107.6x21.7.

12. Interulobites triangularis (Brenner) Phillips and Felix 1971 

Sample D5973, slide 2, coordinates 81.2x15.6.

13. Staplinisporites caminus (Balme) Pocock 1962 

Sample D5803, slide 6, coordinates 96.4x4.4.

14. Staplinisporites caminus (Balme) Pocock 1962

Sample D5803, slide 11, coordinates 82.4x19.8.

15. Lycopodiumsporites sp.

Sample D5803, slide 22, coordinates 74.7x1.2.

16. Matthesisporites tumulosus Doring 1964

Sample D5803, slide 12, coordinates 81.7x21.1.

17. Leptolepidites cf. L. verrucatus Couper 1953

Sample D5803, slide 8, coordinates 90.0x2.2.

18. aff. Cicatricososporites phaseolus (Delcourt and Sprumont) Krutzsch 1959 

Sample D5801, slide 2, coordinates 76.0x15.5.

19. Converrucosisporites cf. C. proxigranulatus Brenner 1963 

Sample D5510-C, slide 2, coordinates 98.4x15.4.

20. Verrucosisporites densus (Bolkhovitina) Pocock 1970 

Sample D5803, slide 6, coordinates 106.1x4.7.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 5

20

GLEICHENIIDITES, UNDULATISPORITES, CYATHIDITES, DELTOIDOSPORA, TODISPORITES, 

DICTYOTRILETES, TIGRISPORITES, CADARGASPORITES, INTERULOBITES, STAPLINISPORITES, 

LYCOPODIUMSPORITES, MATTHESISPORITES, LEPTOLEPIDITES, CICATRICOSOSPORITES, 

CONVERRUCOSISPORITES, AND VERRUCOSISPORITES
PLATE 6 

Burro Canyon Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers, (text fig. 2)]

FIGURE 1. Cicatricosisporites cf. C. minor (Bolkhovitina) Pocock 1964 

Sample D5510-C, slide 1, coordinates 109.4x11.1.

2. Cicatricosisporites cf. C. cuneiformis Pocock 1964 

Sample D5510-C, slide 4, coordinates 100.3x10.0.

3. Cicatricosisporites augustus Singh 1971

Sample D5510-B, slide 1, coordinates 99.0x4.5.

4. Cicatricosisporites cf. C. potomacensis Brenner 1963 

Sample D5510-C, slide 2, coordinates 87.0x5.5.

5. Cicatricosisporites cf. C. mediostriatus (Bolkhovitina) Pocock 1964 

Sample D5510-C, slide 1, coordinates 88.8x5.4.

6. Cicatricosisporites sp.

Sample D5510-A, slide 2, coordinates 92.6x14.7.

7. Cicatricosisporites pseudotripartitus (Bolkhovitina) Dettmann 1963 

Sample D5801, prep. 2, slide 4, coordinates 105.9x20.8.

8. Cicatricosisporites cf. C. pseudotripartitus (Bolkhovitina) Dettmann 1963 

Sample D5510-B, slide 1, coordinates 99.5x16.6.

9. Cicatricosisporites apiteretus Phillips and Felix 1971 

Sample D5510-C, slide 2, coordinates 89.7x10.5.

10. Cicatricosisporites cf. C. subrotundus Brenner 1963

Sample D5510-B, slide 1, coordinates 107.2x13.3.

11-12. Cicatricosisporites cf. C. crassistriatus Burger 1966

Sample D5801, prep. 2, slide 2, coordinates 110.3x1.0.

13. Cicatricosisporites cf. C. pseudotripartitus (Bolkhovitina) Dettmann 1963 

Sample D5510-C, slide 4, cordinates 108.5x13.0.

14. Appendicisporites bilateralis Singh 1971

Sample D5801, prep. 2, slide 4, coordinates 88.3x10.5.

15. Distaltriangulisporites perplexus (Singh) Singh 1971 

Sample D5803, slide 6, coordinates 75.9x10.0.

16. Distaltriangulisporites sp.

Sample D5510-B, slide 1, coordinates 73.0x9.0.

17. Appendicisporites jansonii Pocock 1962

Sample D5801, prep. 2, slide 2, coordinates 109.4x14.1.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 6

CICATRICOSISPORITES, APPENDICISPORITES, AND DISTALTRIANGULISPORITES
PLATE 7 

Burro Canyon Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers, (text fig. 2)]

FIGURE 1. Corollina torosa (Reissinger) Cornet and Traverse 1975 (two specimens) 

Sample D5803, slide 19, coordinates 79.0x20.1.

2. Equisetosporites sp.

Sample D5803, slide 12, coordinates 91.8x11.0.

3. Equisetosporites sp.

Sample D5803, slide 8, coordinates 80.4x12.9.

4. Cycadopites sp.

Sample D5803, slide 4, coordinates 90.8x20.2.

5. Cycadopites sp.

Sample D5803, slide 5, coordinates 105.3x13.6.

6. Cycadopites sp.

Sample D5803, slide 6, coordinates 108.8x12.4.

7. Exesipollenites tumulus Balme 1957

Sample D5803, slide 10, coordinates 76.6x6.1.

8. Araucariacites sp.

Sample D5510-C, slide 1, coordinates 72.2x1.1.

9. Cerebropollenites mesozoicus (Couper) Nilsson 1958 

Sample D5803, slide 3, coordinates 84.2x20.5.

10. Callialasporites segmentatus (Balme) Sukh-Dev 1961 

Sample D5803, slide 8, coordinates 93.2x16.0.

11. Callialasporites sp.

Sample D5510-C, slide 1, coordinates 76.9x18.0.

12. Cerebropollenites mesozoicus (Couper) Nilsson 1958 

Sample D5803, slide 22, coordinates 99.8x13.4.

13. Vitreisporites pallidus (Reissinger) Nilsson 1958 

Sample D5803, slide 21, coordinates 96.5x15.0.

14. Vitreisporites pallidus (Reissinger) Nilsson 1958 

Sample D5510-C, slide 4, coordinates 105.4x4.3.

15. Pristinuspollenites sulcatus (Pierce) B. Tschudy 1973

Sample D5803, slide 3, coordinates 110.8x20.7. 

16-17. Clavatipollenites hughesii (Couper) Kemp 1968 

Sample D5803, slide 12, coordinates 80.0x23.0.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 7

17

COROLLINA, EQUISETOSPORITES, CYCADOPITES, EXESIPOLLENITES, ARAUCARIACITES, 

CEREBROPOLLENITES, CALLIALASPORITES, VITREISPORITES, PRISTINUSPOLLENITES,

AND CLAVATIPOLLENITES
PLATE 8 

Burro Canyon Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers (text fig. 2)]

FIGURE 1. Paleoconiferus asaccatus Bolkhovitina 1956

Sample D5808, slide 21, coordinates 108.1x17.8.

2. Alisporites thomasii (Couper) Pocock 1962

Sample D5510-C, slide 2, coordinates 99.6x1.6.

3. Pityosporites cf. P. divulgatus (Bolkhovitina) Pocock 1970 

Sample D5803, slide 21, coordinates 76.2x13.9.

4. Alisporites grandis (Cookson) Dettmann 1963 

Sample D5803, slide 5, coordinates 85.4x8.2.

5. Pityosporites nigraeformis (Bolkhovitina) Pocock 1970 

Sample D5803, slide 22, coordinates 89.8x21.6.

6. Pityosporites nigraeformis (Bolkhovitina) Pocock 1970 

Sample D5803, slide 22, coordinates 95.1x12.8.

7. Cedripites cf. C. car.ad^nsis Pocock 1962

Sample D5803, slide 21, coordinates 80.8x17.5.

8. Cedripites cretaceus Pocock 1962

Sample D5803, slide 21, coordinates 109.7x17.6
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE-8

PALEOCONIFERUS, ALISPORITES, PITYOSPORITES, AND CEDRIPITES
PLATE 9 

Burro Canyon Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers (text fig. 2)]

FIGURE 1. Podocarpidites ornatus Pocock 1962

Sample D5803, slide 16, coordinates 110.0x10.1.

2. Podocarpidites cf. P. ellipticus Cookson 1947

Sample D5803, slide 5, coordinates 98.7x19.1.

3. Podocarpidites cf. P. ornatus Pocock 1962

Sample D5803, slide 4, coordinates 89.3x11.4.

4. Podocarpidites cf. P. multesimus (Bolkhovitina) Pocock 1962 

Sample D5803, slide 21, coordinates 102.3x20.4.

5. Podocarpidites cf. P. ornatus Pocock 1962

Sample D5803, slide 21, coordinates 109.3x17.5.

6. Podocarpidites radiatus Brenner 1963

Sample D5803, slide 5, coordinates 111.5x9.7.
GEOLOGICAL SURVEY

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Palynological Evaluation of 

Cedar Mountain and 

Burro Canyon Formations, 

Colorado Plateau

By R. H. TSCHUDY, B. D. TSCHUDY, and L. C. CRAIG

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281

A description of the rocks and age determinations of 

the formations based upon their pollen and spore content

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1984
UNITED STATES DEPARTMENT OF THE INTERIOR 

WILLIAM P. CLARK, Secretary

GEOLOGICAL SURVEY 

Dallas L. Peck, Director

Library of Congress Cataloging in Publication Data

Tschudy, Robert H.

Palynological evaluation of Cedar Mountain and Burro Canyon Formations, Colorado Plateau. 

(Geological Survey Professional Paper 1281) 

Bibliography: 24 p. 

Supt. of Docs. No.: 119.16:

1. Palynology Colorado Plateau. 2. Paleobotany Cretaceous. I. Tschudy, Bernadine D. II. Craig, L. C. 

III. Title. IV. Series.

QE993.T746 1984 561'.13'097881 82-600300

For sale by the Branch of Distribution, U.S. Geological Survey 

604 South Pickett Street, Alexandria, VA 22304
CONTENTS

Page

Abstract .............................................. 1

Introduction ............................................ 1

Rock units ............................................. 1

Cedar Mountain Formation ................................. 2

Burro Canyon Formation .................................. 2

Distribution, stratigraphic relations, and interpretation .................... 4

Methods of sample treatment .................................. 4

Location of productive samples ................................. 6

Cedar Mountain Formation ................................. 6

Burro Canyon Formation .................................. 6

Upper horizon ...................................... 6

Lower horizon ...................................... 7

Palynological analysis Cedar Mountain Formation ....................... 7

Landmark evolutionary events in the development of Angiosperm pollen ....... 9

Age of the upper part of the Cedar Mountain Formation ................ 10

Palynological analysis Burro Canyon Formation ........................ 11

Upper horizon ......................................... 11

Palynomorph recovery from upper horizon samples ................. 13

Lower horizon ......................................... 13

Palynomorph recovery from lower horizon samples ................. 15

Age of the upper part of the Burro Canyon Formation ................. 15

Conclusions ............................................. 19

References cited .......................................... 19

ILLUSTRATIONS

[Plates follow index]

PLATES 1-4. Photographs of palynomorphs from Cedar Mountain Formation .

5-9. Photographs of palynomorphs from Burro Canyon Formation . 

FIGURE 1. Graphic sections showing stratigraphic positions of palynomorph collections .............

2. Map of Colorado Plateau area .......................................

3. Histograms showing percentage distribution of major microfossil groups, Cedar Mountain sample .

4. Photomicrographs of organic material from Burro Canyon upper horizon samples ..........

5. Photomicrograph of thin section of Burro Canyon rock showing bedded nature of organic material 

6-8. Histograms showing gross palynomorph recovery from:

6. Burro Canyon samples upper horizon ..............................

7. Burro Canyon upper and lower horizons a comparison .....................

8. Selected intervals Burro Canyon lower horizon .........................

Page

3

5

8

12

13

14

14

16

TABLES

TABLE 1. Relation of geochronologic terms used and age estimates of boundaries in millions of years before present 

2. Stratigraphic ranges of Burro Canyon palynomorph species ............................

Page 

2

18

III

PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND 

BURRO CANYON FORMATIONS, COLORADO PLATEAU

By R. H. TSCHUDY, B. D. TSCHUDY, and L. C. CRAIG

ABSTRACT

By lithologic fades change the Cedar Mountain Formation of eastern Utah passes laterally into the Burro Canyon Formation of western Colorado. Both formations lie between the Dakota Sandstone and 

Morrison Formation. Few fossils have been found in the Cedar Mountain and Burro Canyon Formations, and consequently the age span 

attributed to these formations has been uncertain.

The overlying Dakota Sandstone in these two areas is palynologically of early Cenomanian age. The first occurrence of the angiosperm 

fossil pollen, Nyssapollenites albertensis Singh, found in the basal 

Dakota, is proposed as the palynological indicator of the Early-Late 

Cretaceous boundary in the Western Interior. Palynomorphs found 

in the upper parts of both the Cedar Mountain and Burro Canyon 

Formations are more advanced than are those found in the upper 

part of the Morrison Formation in the same general area. Consequently, the upper parts of the Cedar Mountain and Burro Canyon 

Formations that yielded palynomorphs are palynologically of Early 

Cretaceous age.

The palynomorph assemblage found in the upper part of the Cedar 

Mountain Formation date this horizon as late Albian. The Burro Canyon assemblages were somewhat less distinctive, exhibiting evidence 

of sequential biofacies changes, and one sample exhibited an unusual 

lithotype somewhat suggestive of algal origin. Nevertheless, the 

palynological age of the upper part of the Burro Canyon Formation 

is clearly older than that of the Cedar Mountain sample. The age 

of the Burro Canyon sample is estimated to be Aptian to early Albian 

with the possibility of being as old as Barremian (latest Neocomian). 

Thus, samples from the upper parts of these two physically equivalent 

formations show a difference in age. We speculate that pre-Dakota 

erosion may have removed beds equivalent to the upper Cedar Mountain at the Burro Canyon locality, and that the Neocomian may be 

represented in the still undated lower parts of the Cedar Mountain 

and Burro Canyon Formations.

INTRODUCTION

The Burro Canyon Formation of western Colorado 

and the physically equivalent Cedar Mountain Formation of eastern Utah, both of Early Cretaceous age, 

have received considerable geologic attention since 

their definition by Stokes and Phoenix (1948) and 

Stokes (1944, p. 965-967). Both formations have proved 

valid as mappable units, yet concern remains about the 

age and detailed relations of these formations, both to 

the underlying Morrison Formation of supposed Late 

Jurassic age and to the overlying Dakota Sandstone of 

earliest Late Cretaceous age. All students of the Burro 

Canyon and Cedar Mountain Formations agree that, at

least in part, the formations pass laterally by lithologic 

change into each other.

Upper parts of the Burro Canyon and Cedar Mountain have been interpreted as passing laterally into the 

overlying Dakota Sandstone (Young, 1960, p. 158) and 

as separated from it by an erosional disconformity 

(Craig and others, 1955, p. 161; Carter, 1957, p. 313). 

The Burro Canyon has also been interpreted as intertonguing with the underlying Brushy Basin Member of 

the Morrison Formation (Craig and others, 1961, p. 

1583) and as separated from the Morrison by a disconformity (Young, 1960, p. 169). These differences of interpretation serve to emphasize the importance of age 

determinations from either the Cedar Mountain or 

Burro Canyon Formations and adjoining beds. Unfortunately, both the Cedar Mountain and Burro Canyon 

Formations contain few fossils. Young (1960, p. ISO181) summarized the knowledge of the limited invertebrate fauna and megaflora. The Aptian or Albian Age 

(table 1) determined for these fossils accounts for the 

assignment of the Burro Canyon and Cedar Mountain 

to the Early Cretaceous.

The recognition of palynomorphs in samples from the 

Burro Canyon led to the hope that more could be 

learned from the plant microfossils about the ages of 

the Burro Canyon and Cedar Mountain Formations and 

adjacent beds. Considerable search for likely fossiliferous beds resulted in the collection of numerous samples, 

most of which proved to be barren of palynomorphs. 

A few samples, however, contained suites of 

palynomorphs, and these new data and the interpreted 

ages are presented in this report.

Acknowledgments. We thank Sharon Van Loenen 

for her assistance in the preparation of illustrations, 

the photography of specimens, and other aspects of the 

preparation of this manuscript.

ROCK UNITS

A summary of the characteristics of the Cedar Mountain and Burro Canyon Formations near the fossil sites 

follows; figure 1 shows the stratigraphic position of the 

productive palynomorph collections discussed in this 

paper.
PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

TABLE 1. Relation of geochronologic terms used in this report and 

age estimate of boundaries in millions of years before present, 

based on Lanphere and Jones (1978)

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CEDAR MOUNTAIN FORMATION

The Cedar Mountain consists of a relatively thin basal 

conglomeratic sandstone unit, the Buckhorn Conglomerate Member, and a relatively thick upper shale unit, 

the shale member. The shale member consists of silty 

to sandy swelling mudstones that show relatively thick 

color zones of pastel shades. Some of the mudstone 

units contain abundant limestone nodules that cover the 

weathered slopes of the member. Minor constituents 

of the member are thin, broadly lenticular limestone 

beds, and a few sandstone units, which are generally 

cross bedded, may contain lenticles of granule to pebble 

conglomerate, and appear fluvial in origin. The carbonaceous mudstone from which the palynomorphs were 

collected is almost unique in the Cedar Mountain.

The Cedar Mountain differs from the Burro Canyon 

in that the shale member consists dominantly of pastelcolored claystone, including purples and reds, as well 

as green; it is composed of swelling clays and it generally contains an abundance of limestone nodules that 

cover the weathered slopes. The Cedar Mountain Formation differs from the underlying Brushy Basin Member of the Morrison Formation in that it lacks the brilliant colors of the Brushy Basin, it lacks the distinct 

color banding, and it has abundant limestone nodules. 

The Cedar Mountain is distinguished from the Dakota 

Sandstone by the general absence of carbonaceous 

layers in the mudstone of the Cedar Mountain and the 

presence of carbonaceous shale and plant remains in 

the sandstone beds of the Dakota.

The palynomorph collections reported here come from 

a single carbonaceous unit near the top of the formation 

(fig. 1) in the SEVtSWV*, sec. 17, T. 19 S., R. 9 E., 

Emery County, Utah. The locality is about 16 km 

southwest of the type locality of the Cedar Mountain 

Formation (Stokes, 1952, p. 1773). This carbonaceous 

unit also has provided a small invertebrate and megaflora suite reported by Katich (1951, p. 2093-2094).

BURRO CANYON FORMATION

The Burro Canyon is a sequence of alternating lenticular conglomeratic sandstone beds and variegated, 

mostly greenish-gray, nonswelling mudstone beds. The 

sandstone units generally dominate in the lower part 

of the formation, whereas the mudstone is more abundant in the upper part of the formation. Minor rock 

components are limestone and chert beds.

The formation is distinguished from the underlying 

Brushy Basin Member in that it consists of coarse, generally conglomeratic, sandstone and interbedded dominantly greenish-gray mudstone, composed of nonswelling 

clay. The Brushy Basin contains only a few conglomeratic sandstone beds, particularly in its upper part, and 

is composed dominantly of alternating red, green, and 

gray mudstone that contains swelling clay, and forms 

distinctly color-banded outcrops. The Burro Canyon 

Formation is distinguished from the overlying Dakota 

Sandstone by the greenish mudstone and by the absence of carbonaceous material and organic-rich shale, 

lignite, or coal. The Dakota consists of interbedded 

sandstone and carbonaceous shale; the sandstone is in 

part conglomeratic and generally contains much carbonaceous debris and common impressions of twigs, stems, 

and branches.

The collections of palynomorphs reported here came 

from two carbonaceous shale units (fig. 1) in the upper 

shaly part of the Burro Canyon exposed in a small 

tributary of Disappointment Creek in the NEV4, sec. 

11, T. 43 N., R. 18 W. The fossil locality is 6.2 km 

southeast of the type locality of the Burro Canyon Formation (in Burro Canyon, sec. 29, T. 44 N., R. 18 W., 

San Miguel County, Colo.). Neither of the carbonaceous 

units have been recognized at the type locality. The 

upper carbonaceous unit is the same unit that has pro-
ROCK UNITS

Emery County, Utah

Sec. 34, 35, T. 18 S., R. 9 E.

Sec. 3, 4, T. 19 S., R. 9 E.

Dakota Formation

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Conglomeratic sandstone

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Carbonaceous mudstone 

or shale

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limestone

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or shale

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Fossil-bearing layers

FIGURE 1. Graphic sections showing stratigraphic positions of palynomorph collections. A, Section 

of Cedar Mountain Formation near type locality of formation; fossil-bearing carbonaceous lens 

sketched on basis of position beneath the Dakota Sandstone at fossil locality. B, composite 

section of Burro Canyon Formation measured at fossil localities.
PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

duced a small invertebrate fauna and megaflora reported by Simmons (1957, p. 2525- 2526).

DISTRIBUTION, STRATIGRAPHIC 

RELATIONS, AND INTERPRETATION

The Burro Canyon formation is recognized over a 

broad area in southeastern Utah and western Colorado 

(fig. 2), and recently the name has been extended to 

similar rocks occupying a similar stratigraphic position 

in the Chama basin of north-central New Mexico 

(Saucier, 1974).

The southern limit of the Burro Canyon is an erosional limit where the Burro Canyon is cut out by the 

regional unconformity at the base of the overlying 

Dakota Sandstone. This limit is along a northwesttrending line that passes near the Four Corners. South 

of this limit, the pre-Dakota unconformity progressively 

bevels the Morrison Formation and older formations 

southward.

To the east, beds equivalent to the Burro Canyon 

are believed to be present in central and eastern Colorado (Lytle Formation of Dakota Group along the 

Front Range foothills and Lytle Sandstone Member of 

Purgatoire Formation in southeast Colorado). The 

Burro Canyon itself reaches a poorly known pinchout 

along an irregular north-south line extending from 

northwestern Colorado to northwestern New Mexico 

(fig. 2). The nature of this pinchout is uncertain. In 

part it is probably the result of pre-Dakota erosion, 

but in part it also may be due to depositional thinning 

of the formation. In the poor exposures along the few 

outcrop belts that cross the pinchout, the sandstone 

beds in the Burro Canyon appear to thin as the pinchout 

is approached. However, pre-Dakota erosion seems the 

most important factor in the pinchout of the formation.

The Cedar Mountain Formation is recognized over 

much of south-central and northeastern Utah and northwestern Colorado. The southern limit is south of the 

Henry Mountains and is an erosional limit along which 

the Cedar Mountain is cut out by the erosional unconformity at the base of the Dakota. The western limit 

is poorly known but it extends beneath the high 

plateaus of central Utah. To the north, the formation 

is identified to the Wyoming State line in both northeastern Utah and northwestern Colorado. Equivalent 

beds in Wyoming are included in the Cleverly Formation.

The arbitrary lateral limit between the Burro Canyon 

Formation and the Cedar Mountain Formation is placed 

along the Colorado River in Utah (Stokes, 1952, p. 

1774), although for a distance of about 40 km west of 

the river the characteristics of the two formations intermingle.

To the north in Colorado, the Burro Canyon Formation passes laterally into the Cedar Mountain Formation. In this area north of the Colorado River, the line 

of demarcation between the Burro Canyon and Cedar 

Mountain is placed where Burro Canyon characteristics 

give way to Cedar Mountain characteristics in the subsurface as interpreted from drillhole logs.

Based on thickness, percentage of sandstone, pebble 

size, and limited current-direction studies, the Burro 

Canyon and Cedar Mountain are interpreted as sediments from two alluvial systems deposited across a 

broad even surface on top of the Morrison Formation; 

in many respects they appear to represent a continuation of Morrison deposition. The major source for the 

Burro Canyon was southwest of the Four Corners, 

perhaps in southern Arizona. Burro Canyon deposits 

were spread northward and eastward from a major depositional axis along the southern part of the Utah-Colorado State line. The source for the Cedar Mountain 

Formation was somewhere west of the high plateaus 

in central Utah, and Cedar Mountain deposits were 

spread eastward.

METHODS OF SAMPLE TREATMENT

Samples were first cleaned, then broken into fragments about 1-5 mm (millimeters) in diameter. 10-20 

g (grams) of broken rock were placed in plastic beakers 

and tested for the presence of carbonates. If carbonates 

were present, the samples were then treated with 10- 

percent HC1 to remove carbonates; otherwise they were 

treated directly with hydrofluoric acid to disaggregate 

and partly dissolve the inorganic matrix. After thorough washing, the centrifuged residue was treated with 

the oxidizing Schulze1 solution (HN03 + NaCl)03). After 

washing, the acid humates were solubilized and removed by a short treatment with 10-percent NaOH solution. Pollen and spores (and insoluble organic matter) 

were concentrated from the residue by flotation in zinc 

bromide solution (specific gravity about 2.0) and then 

"panned" by means of the technique suggested by 

Funkhouser and Evitt (1959). The palynomorphs were 

then stained with Bismark Brown, if necessary, and 

then mixed with Vinylite AYAF in 90-percent alcohol 

(polyvinyl acetate plastic, refractive index 1.466).

Several drops of the palynomorph-plastic mixture 

were placed on a 22x40 mm cover glass and another 

cover glass was placed on the mixture, thus making 

a "sandwich." After the plastic had spread evenly to 

the margins, the cover glasses were separated by sliding them in opposite directions lengthwise in much the

"Trade names used in this paper are for descriptive purposes only and do not constitute 

endorsement by the U.S. Geological Survey.
METHODS OF SAMPLE TREATMENT

111° 110

FIGURE 2. Map of Colorado Plateau area showing fossil sample localities, sample numbers, and distribution of Cedar Mountain (Kem) 

and Burro Canyon (Kbc) Formations. Zero line marks pinchout of Burro Canyon and Cedar Mountain Formations (dashed where 

uncertain). Dotted line is arbitrary line separating areas in which Burro Canyon and Cedar Mountain are recognized.
PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

same manner as a blood smear is made. After the film 

on the cover glasses had dried for a few minutes on 

a warming plate, the cover glasses were inverted and 

mounted on slides using Histoclad resin. This method 

provides a thin, evenly dispersed film of pollen and 

spores in a mountant of favorable refractive index. It 

serves to anchor the fossils close to the cover glass so 

that they can be examined conveniently even under 

high-power oil-immersion lenses.

Slides are identified by locality number (D5510-A), 

and slide number D5510-A (1) or D5510-A (2); and on 

occasion processing sequence is also included as preparation 1 (prep. 1, prep. 2) and fraction heavy fractions, 

fine fraction (Hvs; fines.): for example, D5785-A, prep. 

4, Hvs., slide 5.

Minor modifications of oxidation time, cleaning procedures, and staining were tried with some success in 

efforts to improve the quality of some preparations.

LOCATION OF PRODUCTIVE SAMPLES 

CEDAR MOUNTAIN FORMATION

Two Cedar Mountain samples were obtained from the 

locality known as the Stokes-Katich locality (Simmons, 

1957, p. 2527). Samples were taken from a 1.5-m-thick, 

dark-gray calcareous shale outcrop in a cliff. The outcrop was about 13.9 m below the Dakota contact. The 

lower sample, consisting of gray calcareous siltstone interspersed with small calcite crystals, was barren of 

palynomorphs. The upper sample, consisting of darkgray laminated shale and black claystone, was productive and was assigned a USGS paleobotany locality 

number as indicated below:

USGS

paleobotany

loc. No.

Field No. Locality

D5785 3RT-77-7 SE1/4SW1/4 sec. 17, T. 19 S., R. 9 E., 

1A mi west of the junction of Rock 

Canyon Creek and Cottonwood 

Creek, Emery County, Utah. 

(Stokes-Katich locality in Simmons, 

1957, p. 2527).

BURRO CANYON FORMATION 

UPPER HORIZON

Productive samples were obtained from two horizons. 

The upper horizon consisted of a 1.5-m-thick layer of 

black fissile shale located 7.3 m below the base of the 

Dakota Sandstone and immediately above a prominent 

limestone ledge. This is the same general locality from 

which fossils were collected by Stokes (1952) and the 

identical locality visited by G. C. Simmons and D. R.

Shawe, and later revisited by L. C. Craig and others 

(Simmons, 1957, p. 2525). Several collections for 

palynological examination were taken from this locality 

during the summer of 1976. The yield of palynomorphs 

from these samples was so poor that resampling was 

conducted at the same site and along the lateral extent 

of the outcrop in the summer of 1977 and again in 1978. 

Sample number and localities for the upper horizon of 

the Burro Canyon Formation are listed below:

USGS

paleobotany

loc. No.

Field No. Locality

D5510-A RT-76-6 1/4NW1/4NE1/4 sec. 11, T. 43 N., R. 18 

W., in northwest wall of an intermittent stream bed about 330 m south 

of its junction with Disappointment 

Creek, Hamm Canyon quadrangle, 

San Miguel County, Colo. Approximately 1.5-m-thick ledge of black fissile shale, 7.3 m below Burro CanyonDakota contact. Sample 25 cm above 

limestone ledge at base of shale.

D5510-B RT-76-7 Same locality as D5510-A, 31 cm above 

limestone ledge.

D5510-C RT-76-8 Same locality as D5510-A, 61 cm above 

limestone ledge.

D5786-A RT-77-15 Same locality as D5510-A, top part of 

limestone ledge.

D5786-B RT-77-16 90 m S. 5° E., from locality of D5510-A, 

along strike of black fissile shale. 1- 

cm-thick basal siltstone layer immediately above limestone ledge.

D5800 RT-77-17 Same locality as D5786-B. Black, wet 

mudstone, 60 cm above limestone 

ledge.

D5801 RT-77-18 Same locality as D5786-B. Black fissile 

shale with limestone concretions 18 

cm above limestone ledge.

D5802 RT-77-19 S. 60° W., 200 m from sample D5801; 

sample from northwest side of drainage. Composite sample from 1.5-mthick black fissile shale.

D5974 RT-78-18 NW corner sec. 13, T. 43 N., R. 18 W., 

along unimproved road, Hamm Canyon quadrangle, San Miguel County, 

Colo. About 1.5-m-thick black fissile 

shale. Same horizon as previous 

Burro Canyon samples, but only 3 m 

below the Dakota contact.

The upper horizon of black fissile shale has been 

traced several kilometers to the northwest and to the 

southeast of the original locality, but is apparently absent from the type locality of the Burro Canyon Formation in Burro Canyon near the village of Slick Rock, 

Colo., sec. 29, T. 44 N., R. 18 W., San Miguel County, 

Colo.
LOCATION OF PRODUCTIVE SAMPLES

LOWER HORIZON

In 1976 during the course of recollecting samples from 

the localities just described, a black limy shale horizon 

was found about 10.4 m below the base of the 1.5-mthick black fissile upper-shale horizon. This sample 

yielded a much better assemblage of palynomorphs than 

was obtained from the upper fissile-shale horizon. The 

sample consisted of two lithotypes a fine-grained, 

hard, calcareous black shale, and a black, soft, friable 

shale containing small calcite crystals. Palynomorph 

yield from the two lithotypes was distinctly different, 

suggesting that biofacies near the site of deposition had 

changed. The site was recollected in 1978. Six samples 

were collected from an 87-cm interval (fig. 8). Four of 

these samples were productive and were given USGS 

paleobotany locality numbers as indicated below:

USGS

paleobotany

loc. No.

Field No. Locality

D5803

D5972-A,B,

C,D 

D5973

RT-77-20 SW1/4NE1/4 sec. 11. T. 43 N., R. 18 W., 

at approximate location of bench 

mark 5641, Hamm Canyon quadrangle, 1960, 10.4 m below base of 

upper fissile-shale horizon. Sample included two lithotypes; soft, black friable shale with small calcite crystals, 

and hard, dark-gray calcareous shale.

RT-77-20 Same locality as D5803. See figure 8.

RT-78-16 Same locality as D5803 but 10.2 m north 

along strike of dark-gray and black 

outcrop. Sample from bentonite zone, 

friable black shale that grades upward into dark-gray to black limestone. Composite sample from 30-cm 

interval.

The lower horizon was traced about 150 m along the 

wash, but apparently is not present or is covered elsewhere.

PALYNOLOGICAL ANALYSIS CEDAR 

MOUNTAIN FORMATION

Reports of fossils from the Cedar Mountain Formation are exceedingly sparse. The pertinent information 

concerning those few fossils found is presented by Simmons (1957) who listed fossils from two localities. The 

first locality, the socalled Stokes-Katich locality, is the 

same locality mentioned previously that yielded the 

palynomorphs in the present study. Fossils found include Eupera onestae McLearn, a fresh-water

pelecypod of Aptian Age, Tempskya minor Reed and 

Brown, a tree fern trunk, known from the Aspen Shale 

(Albian Age) Wyoming and Idaho, ostracods, and 

ganoid fish scales. "The second locality is in sec. 22, 

T. 22 S., R. 20 E., on the southwest flank of the Salt 

Valley anticline, Grand County, Utah" (Simmons, 1957, 

p. 2527). This locality yielded ostracods, gastropods, 

microfossil material, and the charophyte Clavator harrisi Peck.

The microfossil material was examined by R. E. Peck 

who stated: "All of these are common fossils in the Gannett Group, the Cleverly of northwestern Wyoming, 

and the limestones in the upper Kootenai of Montana. 

Clavator harrisi Peck is common in the Trinity of the 

Gulf Coast. None of these species occurs in the Morrison of the Front Range of Colorado, in eastern Wyoming or in the Black Hills. Their occurrence is an excellent indication of the Lower Cretaceous age of the formation" (in Simmons, 1957, p. 2527). The purported 

age of the Gannett Group is Early Cretaceous, of the 

Cleverly and Kootenai Formations is Aptian, and of the 

Trinity Group of the Gulf Coast, is Aptian to early Albian. "In view of the identifications, an Early Cretaceous age seems assured for the shale member of the 

Cedar Mountain Formation" (Simmons, 1957, p. 2527).

Angiosperm wood was collected from the Cedar 

Mountain Formation near Castle Dale and Ferron, 

Utah by Thayn (1973). Genera found were Icacinoxylon, previously known only from the Tertiary of 

Europe, and Paraphyllanthoxylon, known from the 

Cretaceous of Arizona, Idaho, and Alabama. However, 

these fossils shed no additional light upon the age of 

the Cedar Mountain Formation.

The samples collected for our study were examined 

palynologically in an attempt to obtain a more definite 

age determination and to verify the reported correlations of the Cedar Mountain and Burro Canyon Formations (Simmons, 1957; Craig and others, 1955).

Palynomorphs were poorly preserved and somewhat 

sparse, requiring the intensive examination of many 

slides in order to obtain a significant assemblage. The 

palynomorph assemblage consisted of tricolpate angiosperm pollen, bisaccate conifer pollen, monosulcate pollen, Corollina and minor representations of Liliacidites, trilete spores and taxodiaceous pollen (fig. 3). The 

high percentage of unidentified palynomorphs (averaging 32 percent of the assemblage) attests to the generally poor condition of the palynomorphs present. Figure 

3 includes counts of palynomorph types in four separate 

preparations. Modification of preparation procedures 

were tried in attempts to obtain better recovery from 

this sample. That some of the preparations were better 

than others is evident upon examination of the graph. 

For example, preparation C (D5758-B, prep. 2) yielded
PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

50-n

40 

30-

20 

10

Slides counted

A 05785(2) First preparation 

B D5785-A(2) Second preparation 

C D5785-B(2) Second preparation 

D D5785-A(1) Fourth preparation 

lii Average

A B C D 

Bisaccate 

pollen

A B C D 

Carol I in a

A B C D 

Tricolpate 

pollen

A B C D 

Monosulcate 

pollen

A B C D 

Trilete 

spores

A B C D 

Liliacidites

A B C D 

Taxodiaceaepollenites

A B C D 

Unidentified

FIGURE 3. Percentage distribution of major plant microfossil groups from several preparations of the productive Cedar Mountain sample.

only 6 percent bisaccate conifer pollen, and the unidentified palynomorphs accounted for 47 percent of the assemblage. In contrast, preparation A (D5758, prep. 1) 

yielded 21 percent bisaccate conifer pollen and only 19 

percent unidentified palynomorphs. Except for discrepancies accounted for by the varied preparation procedures, the recovery of the several palynomorph 

groups shows a remarkable consistency.

The following genera and species have been identified 

from the preparations, and the taxa are shown on plates

Laevigatosporites cf. L. belfordii Burger 1976 

Laevigatosporites gracilis Wilson and Webster 1946 

Cyathidites australis Couper 1953 

Todisporites sp.

Todisporites minor Couper 1958 

Gleicheniidites senonicus Ross 1949 

Lygodiumsporites sp. 

Deltoidospora hallii Miner 1935

Cyathidites minor Couper 1953

Dictyotriletes granulatus Pocock 1962

Foraminisporis sp.

Foraminisporis cf. F. wonthaggiensis (Cookson and

Dettman) Dettmann 1963 

Concavissimisporites variverrucatus (Couper) Singh

1964 

Concavissimisporites punctatus (Delcourt and

Sprumont) Brenner 1963 

Leptolepidites sp. 

Baculatisporites comaumensis (Cookson) Potonie

1956 

Pilosisporites trichopapillosus (Thiergart) Delcourt

& Sprumont 1955

Echinatisporis varispinosus (Pocock) Srivastava 1975 

Cicatricosisporites hughesii Dettmann 1963 

Cicatricosisporites sp. 

Cicatricosisporites cf. C. minutaestriatus (Bolkhovitina) Pocock 1964
LOCATION OF PRODUCTIVE SAMPLES

Cicatricosisporites venustus Deak 1963

Distaltriangulisporites cf. D. irregularis Singh 1971

Costatoperforosporites sp.

Psilatriletes circumundulatus Brenner 1963

Densoisporites microrugulatus Brenner 1963

Densoisporites velatus Weyland and Krieger 1953

cf. Schizosporis sp.

Alisporites grandis (Cookson) Dettmann 1963

Pityosporites granulatus Phillips and Felix 1971

Pityosporites nigraeformis (Bolkhovitina) Pocock

1970b

Pristinuspollenites sulcatus (Pierce) B. Tschudy 1973 

Cedripites cf. C. cretaceus Pocock 1962 

Cedripites canadensis Pocock 1962 

Podocarpidites multesimus (Bolkhovitina) Pocock

1962

Podocarpidites cf. P. minisculus Singh 1964 

Podocarpidites sp.

Vitreisporites pallidus (Reissinger) Nilsson 1958 

Cycadopites carpentieri (Delcourt and Sprumont)

Singh 1964

Monocolpopollenites sp. 

Ginkgocycadophytus cf. G. nitidus (Balme) de Jersey

1962

Equisetosporites multicostatus (Brenner) Norris 1967 

Taxodiaceaepollenites hiatus (Potonie) Kremp 1949 

Eucommiidites sp. 

Corollina torosa (Reissinger) Cornet and Traverse

1975

Exesipollenites tumulus Balme 1957 

Asteropollis asteroides Hedlund & Norris 1968 

Clavatipollenites hughesii (Couper) Kemp 1968 

Liliacidites sp.

Liliacidites cf. L. peroreticulatus (Brenner) Singh

1971 

Tricolpites crassimurus (Groot and Penny) Singh

1971 

Retitricolpites cf. R. virgeus (Groot, Penny and

Groot) Brenner 1963 

Retitricolpites vulgaris Pierce 1961

Retitricolpites vennimurus Brenner 1963 

Striatopollis paraneus (Norris) Singh 1971 

Rousea georgensis (Brenner) Dettman 1973 

Cupuliferoidaepollenites parvulus (Groot and Penny)

Dettmann 1973 

Cupuliferoidaepollenites minutus (Brenner) Singh

1971

Tricolpites cf. T. wilsonii Kimyai 1966 

Tricolpites cf. T. sp. 1 of Kemp (1968) 

Tricolpites micromunus (Groot and Penny) Singh

1971

Tetracolpites cf. T. pulcher Srivastava 1969 

Tetracolpites sp.

LANDMARK EVOLUTIONARY EVENTS IN THE 

DEVELOPMENT OF ANGIOSPERM POLLEN

The earliest records of angiosperm pollen include 

some of the same taxa that were recovered from the 

Cedar Mountain Formation. The first occurrences of angiosperm pollen in the stratigraphic record and the subsequent diversification of angiosperm pollen is pertinent 

to the age determinations and conclusions derived from 

Cedar Mountain samples.

The stratigraphic record has provided the basis for 

several outlines of the developmental history of angiosperm pollen, particularly in North America (Singh, 

1971, 1975; Doyle, 1969; Jarzen and Norris 1975; Norris, 

Jarzen, and Awai-Thorne, 1975; Muller, 1970; and 

others). These outlines present data concerning the earliest record of angiosperm pollen, followed successively 

by the first appearance of tricolpate pollen, tricolporate 

pollen, triporate pollen; and in the Cenomanian and 

later stages, the times of origin of evolutionarily more 

advanced pollen types.

There are no substantiated pre-Cretaceous records 

of angiosperm pollen. The most primitive putative angiosperm pollen type is a monosulcate grain with pilate 

or retipilate sculpture, represented by the genus 

Clavatipollenites Couper. Couper (1958), in describing 

the type species C. hughesii from the Barremian of 

England, pointed out that although the monosulcate 

aperture condition is prevalent in gymnosperms, pilate 

or retipilate sculpture is not known outside the angiosperms. Pollen grains of the Clavatipollenites type are 

now considered by the vast majority of palynologists 

to be of probable angiosperm origin. Clavatipollenites 

pollen has been widely reported in rocks of Aptian-Albian Age from diverse parts of the world: Hughes 

(1958) and Kemp (1968) from England, Couper (1964) 

from Central America and Australia, Kemp (1968) and 

Norris (1967) from western Canada, and Brenner (1963) 

from eastern United States. Chlonova (1977) reported 

the first find of Clavatipollenites in ?Albian-Cenomanian rocks of Western Siberia. She discussed the preBarremian (Jurassic) records of identifications of 

Clavatipollenites (from central Europe and Asia) and 

rejected them as not being completely reliable. Birkelund, and others (1978) and Vigran and Thusu (1975) 

reported Clavatipollenites from Jurassic and pre-Jurassic rocks of Norway. Perhaps significantly, Birkelund 

and others (1978) found Clavatipollenites in their assemblage 1 (Middle Jurassic) but not in younger assemblages assemblage 2 (Kimmeridgian), assemblage 

3 (Kimmeridgian-Volgian), and assemblage 4 (early 

Neocomian).

In North America, the oldest record of Clavatipollenites is from the upper part of the Barremian (Doyle, 

1969; Doyle and Robbins, 1977). In western Canada,
10 PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

the entrance level of Clavatipollenites coincides in Alberta with the entrance level of reticulate tricolpate 

forms (middle Albian). Clavatipollenites was not found 

in Canada in the Loon River Formation, lower mid-Albian (Singh, 1975), nor in the Mannville Group (Singh, 

1964; Norris, 1967) of Aptian to early middle Albian 

age and no older than late Barremian (Singh, 1964). 

Thus, in western North America there are no records 

of Clavatipollenites earlier than mid-Albian time. The 

presence of specimens of Clavatipollenites in Cedar 

Mountain rocks therefore suggests an Albian or 

younger age.

Tricolpate pollen first appears, apparently 

worldwide, in the Albian. "The appearance of tricolpate 

pollen seems to have been a major world-wide event, 

and in all areas which have been carefully studied there 

is a zone with small reticulate tricolpates but without 

triporates or typical tricolporates (cf. Krutzsch, 1963; 

Muller, 1968). This appearance generally may be dated 

as early or middle Albian, but refinement is needed 

in most areas." (Doyle, 1969, p. 11). Singh (1971, p. 

25) has summarized these data as follows: "The entrance of tricolpate dicotyledonous pollen in Albian 

strata of North America has been well documented by 

Brenner (1963), Davis (1963), Pannella (1966), Norris 

(1967), and Hedlund and Norris (1968). In other parts 

of the world, the first definite dicotyledonous pollen has 

been reported from Albian strata of central Russia (Bolkhovitina, 1953), New Zealand (Couper, 1960), Portugal 

(Groot and Groot, 1962), Central America and Africa 

(Couper, 1964), Peru (Brenner, 1968), Australia (Dettmann and Playford, 1968) and England (Kemp, 1968). 

Thus the entrance of tricolpate dicotyledonous pollen 

in the Lower Cretaceous succession of the Peace River 

area supports the middle to late Albian age assigned 

to these beds on faunal evidence (Wickenden, 1951, 

Stelck, etal., 1956)."

The angiosperm pollen succession in eastern Australia was discussed by Dettmann (1973). She reported 

that the earliest occurrence of tricolpate pollen was 

found in the middle Albian of the Great Artesian Basin, 

whereas tricolpate pollen first appears a little later, in 

the upper Albian, in the more southerly Otway Basin. 

The first occurrence of tricolpate angiosperm pollen in 

Australia appears to coincide in time with its first appearance in Western North American rocks.

Tricolporate pollen first appears in latest? Albian 

time in western Canada and western United States and 

in the early Cenomanian in eastern United States 

(Singh, 1975). Tricolporate pollen has a widespread distribution throughout the Cenomanian of the Western 

Interior. Singh (1975, p. 377) concluded "It is evident 

from the above discussion that the Albian-Cenomanian 

boundary in North America is marked by the appearance of smooth, triangular tricolporates (Table II, III) 

and angiosperm tetrads."

The tricolporate pollen mentioned by Singh (1975) is 

the species Nyssapollenites albertensis Singh. It appears just below the fish scale member in the Shaftesbury Formation of Alberta (uppermost Albian). The 

same species identified as Tricolporopollenites aliquantulus Hedlund was found in the Red Branch Member 

of the Woodbine Formation of Oklahoma (Cenomanian) 

(Hedlund, 1966). Pannella (1966) reported the same 

species (as Tricolporites dakotensis) from the upper 

part of the Dakota Sandstone and the Huntsman Shale 

of MacKenzie (1965) (upper Albian-Cenomanian) of the 

Denver basin, Colorado. The same species (as Tricolporopollenites aliquantulus Hedlund) was found in the 

Dakota Sandstone of Arizona (Cenomanian) by Agasie 

(1969). We have found pollen of Nyssapollenites albertensis Singh to be a common constituent of Cenomanian 

rocks of Colorado and Utah. In the Front Range near 

Denver, Colo., the entrance level of this species is in 

the middle part of the Kassler Sandstone Member of 

the South Platte Formation (Dakota Group) about 30.5 

m below the base of the Benton Formation (Mowry 

Shale to the north). The Mowry Shale is characterized 

by abundant fish scales, and is found at approximately 

the same stratigraphic position as the "fish scale marker 

bed" ("The traditional Lower-Upper Cretaceous boundary***" (Norris and others, 1975) in the Shaftesbury 

Formation of Alberta Canada. Significantly, Singh 

(1971, p. 28) found the entrance level of Nyssapollenites 

albertensis at about 35.0 m below the "fish scale marker 

bed." With the exceptions of the latest Albian report 

by Singh (1971) and the late Albian (Dakota) report 

by Pannella (1966), all other records of tricolporate pollen from western North America are from Cenomanian 

and younger rocks. The consistent first occurrence of 

Nyssapollenites albertensis at or very near the AlbianCenomanian boundary provides a reliable indicator in 

western North America of the palynological boundary 

between the Early and Late Cretaceous. This 

palynological marker species coincides with or is close 

to the Early-Late Cretaceous boundary based on other 

types of evidence.

AGE OF THE UPPER PART OF THE 

CEDAR MOUNTAIN FORMATION

The absence of any tricolporate pollen eliminates the 

possibility of a Cenomanian Age. The presence of small 

tricolpate pollen indicates an age range from middle to 

late Albian. The presence of at least 11 identified 

species of tricolpate pollen suggests that a significant 

amount of time must have elapsed since the origin of 

tricolpates in the mid Albian, until the plants had 

evolved to produce the diverse tricolpate flora including 

such large forms as Tetracolpites pulcher Srivastava.
PALYNOLOGICAL ANALYSIS BURRO CANYON FORMATION 11

Thus, this assemblage is clearly of late or latest Albian 

age.

PALYNOLOGICAL ANALYSIS BURRO 

CANYON FORMATION

The Burro Canyon Formation also has yielded few 

fossils. Fossil evidence for the age of the Burro Canyon 

Formation was presented by Stokes (1952) and Simmons (1957). The fossils were obtained from the 

NE1/4NW1/4NE1/4 sec. 11, T. 43 N., R. 18 W., San 

Miguel County, Colo. This locality is the identical locality that yielded palynomorphs from the upper Burro 

Canyon horizon mentioned previously. The following 

fossils of possible age significance were reported:

Plant Frenelopsis varians Fontaine (Aptian-early 

Albian)

Molluscs Protelliptio douglassi Stanton (Aptian) 

"Unw"farri Stanton (Aptian) 

Nipponaia asinaria Reeside (Early Cretaceous)

No other reports of fossils from the Burro Canyon Formation have come to our attention.

A second locality that yielded palynomorphs, about 

10.4 m below the base of the upper Burro Canyon horizon, has been mentioned previously. No other types 

of fossils are known from this second locality.

As with the Cedar Mountain Formation, the Burro 

Canyon Formation samples were examined palynologically in an attempt to obtain a more refined age determination, to address the question raised by reported 

intertonguing of the basal part of the Burro Canyon 

and upper part of the Morrison Formations (Simmons, 

1957, p. 2523), and to attempt to determine whether 

or not the Burro Canyon and Cedar Mountain Formations are correlative palynologically.

The overlying Dakota Sandstone in this area is 

palynologically of early Cenomanian age (it has yielded 

Nyssapollenites albertensis Singh). The Burro Canyon 

Formation lies between the Dakota and the Morrison. 

In some places, evidence exists of apparent continuous 

deposition from the Morrison into the basal part of the 

Burro Canyon. Samples obtained from the upper or 

Brushy Basin Member of the Morrison Formation in 

this general area have yielded a palynological suite of 

fossils indicative of a Late Jurassic age. Theoretically, 

the Burro Canyon Formation could represent an age 

ranging from Late Jurassic to Cenomanian that is, the 

entire Early Cretaceous spanning a time interval of 

some 40 million years.

UPPER HORIZON

As has been indicated, two palynologically productive 

horizons were found in the upper part of the Burro 

Canyon Formation. The upper horizon sample, from a

1.5-m-thick layer of black fissile shale about 7.3 m below 

the base of the Dakota Sandstone, yielded sparse assemblages of palynomorphs. The great majority of the 

organic matter consisted of what appeared to be short 

filaments (fig. 4A). On closer examination these filaments proved to be aggregates of amorphous material. 

At higher magnification, the apparent strands lose their 

continuity and appear as small strands with somewhat 

indefinite margins (fig. 4B). In the lower part of the 

photomicrograph (fig. 4B) a fragment of black woody 

tissue can be seen. Near the center a palynomorph is 

obscured by this organic material. At succeedingly 

higher magnifications (fig. 4C, D, and E scanning electron micrographs), the organic material exhibits its 

amorphous character, and the filamentous attribute effectively disappears. Contrast between upper-horizon 

preparations containing an abundance of amorphous organic material and more nearly normal preparations is 

shown on a photomicrograph of a preparation from the 

lower horizon (fig. 4P). Wood fragments, bits of epidermal and cuticular tissue, and easily recognizable 

palynomorphs are visible. This preparation is virtually 

devoid of organic material of the kind found in upper 

horizon samples. The great abundance of amorphous organic material present in upper horizon samples could 

not be removed from the samples by oxidation without 

destroying the accompanying palynomorphs. Thus, the 

few spores and pollen grains present were commonly 

obscured by this material. Samples from the upper horizon are unique in this respect in our experience. We 

have never found samples that reacted in the same 

manner. The closest observed similarity is to samples 

of oil shale from the Green River Formation, yet the 

organic material in the Green River oil shale appears 

visually to be distinctly different.

Two samples of black fissile shale from the upper 

horizon were submitted to L. G. Schultz, U. S. Geological Survey, Denver, Colo. for X-ray analysis. He reported that the nonorganic part of the black shale contained 2-10 percent calcite, 1 to 2 percent quartz, and 

a large percentage of mixed-layer illite-smectite, a 

swelling clay that could be an altered tuff.

Thin sections made from this upper horizon shale 

show the abundance and bedded nature of the unaltered 

organic material but give no hint of its original composition (fig. 5). These thin sections, plus macerated sample 

material from the upper horizon were sent to the late 

Dr. J. M. Schopf, USGS Coal Geology Laboratory at 

Columbus, Ohio. He remarked (written commun., Dec. 

13, 1977) "The thin sections are excellent ... I wish 

I could suggest how such a rock could reasonably be 

deposited. My next suggestion is that it must be an 

unusual local occurrence."

This abundant amorphous organic material possibly 

could be the residue from some, as yet unidentified,
12 PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

- ,

-, %

f

\J
PALYNOLOGICAL ANALYSIS BURRO CANYON FORMATION 13

""SM,- >-*fe .. ».^ * - t

FIGURE 5. Burro Canyon-upper horizon sample D5510-A. Thin section of whole rock showing bedded nature of organic material, 

x 100.

alga. Botryococcus, a common lacustrine alga, has been 

found in all upper horizon samples.

PALYNOMORPH RECOVERY FROM 

UPPER HORIZON SAMPLES

The palynomorph recovery from upper horizon samples was sparse. The abundant organic matter and the 

comparatively poor state of preservation made identification extremely difficult. Gross palynomorph recovery from representative upper horizon samples is shown 

in figure 6. The average number of unidentified forms 

was 48 percent, attesting to the difficulty posed by the 

amorphous organic material.

The following identified taxa were obtained from an 

examination of more than 60 slides.

Burro Canyon upper horizon

Undulatisporites cf. U. fossulatus Singh 1971

Cyathidites minor Couper 1953

Todisporites minor Couper 1958

Dictyotriletes pseudoreticulatus (Couper) Pocock

1962 

Cadargasporites reticulatus de Jersey and Paten

1964

Staplinisporites caminus (Balme) Pocock 1962

Matthesisporites tumulosus Boring 1964

aff. Cicatricosisporites phaseolus (Delcourt and

Sprumont) Krutzsch 1959 

Converrucosisporites cf. C. proxigranulatus Brenner

1963 

Cicatricosisporites cf. C. minor (Bolkhovitina)

Pocock 1964

Cicatricosisporites cf. C. cuneiformis Pocock 1964 

Cicatricosisporites augustus Singh 1971 

Cicatricosisporites cf. C. potomacensis Brenner 1963 

Cicatricosisporites cf. C. mediostriatus (Bolkhovitina) Pocock 1964 

Cicatricosisporites sp. 

Cicatricosisporites pseudotripartitus (Bolkhovitina)

Dettmann 1963

Cicatricosisporites apiteretus Phillips and Felix 1971 

Cicatricosisporites cf. C. subrotundus Brenner 1963 

Cicatricosisporites cf. C. crassistriatus Burger 1966 

Distaltriangulisporis sp. 

Appendicisporites bilateralis Singh 1971 

Appendicisporites jansonii Pocock 1962 

Corollina torosa (Reissinger) Cornet and Traverse

1975

Equisetosporites spp. 

Araucariacites sp. 

Callialasporites sp.

Vitreisporites pallidus (Reissinger) Nilsson 1958 

Alisporites thomasii (Couper) Pocock 1962 

Alisporites grandis (Cookson) Dettmann 1963 

Cedripites cf. C. canadensis Pocock 1962 

Cedripites cretaceus Pocock 1962 

Podocarpidites ornatus Pocock 1962 

Burro Canyon taxa are shown on plates 5-9.

LOWER HORIZON

This locality was found about 10.4 m below the upper 

fissile shale horizon. The recovery of palynomorphs was 

much better than from upper horizon samples even 

though preservation quality was not the best. The difference in appearance of the slides from the two horizons is shown on figure 4. In figure 4F fusainized wood 

fragments are prevalent in the photograph, and epidermal tissue and palynomorphs make up the lighter, more 

translucent material. The appearance of the organic material from the lower horizon is normal, in contrast to

FIGURE 4 (facing page). Burro Canyon-upper horizon sample. A, After HF treatment and flotation in ZnBr2 water mount, x 500. B, 

Standard treatment. Mounted in AYAF and histoclad. x 1000. Note wood fragment at center lower margin, and palynomorph at 

center, obscured by organic material. C, Electron micrograph x 5000. D, Electron micrograph x 16000. E, Electron micrograph x 

20,000. F, Lower horizon sample showing more normal appearance of material on slide; xlOO. Note epidermal tissue at upper left 

corner and several palynomorphs.
14

60 -|

PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

60

50 -

40 -

o 30 -

20 -

10 

Slides counted 

A D5786-B(2) 

B 05801(1) 

C D5510-C(1) 

p3 Average

ABC 

Bisaccate 

pollen

ABC 

Corollina

ABC 

Trilete 

spores

ABC 

Other

ABC 

Unidentified

FIGURE 6. Gross palynomorph recovery from some upper horizon 

Burro Canyon samples.

the appearance of the organic material from the upper 

horizon.

A comparison of the gross palynomorph recovery 

from the upper and lower horizons is shown in figure 

7. The contrast is shown vividly by the absence of unidentified forms from the lower horizon. The lower horizon assemblage is dominated by bisaccate conifer pollen 

and Corollina, The residue of palynomorphs makes up 

less than 3 percent of the total assemblage.

The first samples collected from the lower horizon 

showed a marked difference in recovery from hard

Upper horizon Lower horizon

m

FIGURE 7. Comparison of gross palynomorph recovery from Burro 

Canyon upper and lower horizons. Average recovery data for 

upper horizon taken from figure 5. Average recovery data from 

lower horizon taken from figure 8. Unidentified fossils may consist of Corollina, and possibly unidentified algae. Botryococctis 

is present in all samples but commonly is not abundant.

dark-gray shale and from black friable shale containing 

small calcite crystals. The hard dark-gray shale (interval C, fig. 8) was dominated by bisaccate conifer pollen 

and the black friable shale (interval D, fig. 8) by Corollina pollen. The lower horizon was therefore recollected 

the following year in an attempt to verify these data. 

The possibly productive interval consisted of 87 cm of
PALYNOLOGICAL ANALYSIS BURRO CANYON FORMATION 15

alternating shale, calcareous shale, and limestone capped by 40 cm of blocky gray limestone. Six samples 

were taken from the 87-cm interval as shown on figure 

8.

PALYNOMORPH RECOVERY FROM 

LOWER HORIZON SAMPLES

The upper two samples were barren. The gross 

palynomorph recovery of the four lower samples is 

shown in figure 8. The sample D5972-D yielded 97 percent bisaccate conifer pollen and only 1 percent Corollina, whereas samples D5972-C, D5972-B and D5972-A 

yielded 20, 23, and 35 percent bisaccate conifer pollen, 

respectively, and the assemblages were dominated by 

abundant Corollina specimens. Bisaccate pollen and 

pollen of Corollina were produced by conifers. Corollina pollen was produced by the fossil tree genus 

Cheirolepis. The prominent change in abundance of 

these two pollen groups in a comparatively short 

stratigraphic interval indicates a prominent floral 

change and suggests a prominent biofacies difference 

between the two groups of samples.

The following taxa were identified from the lower 

horizon:

Gleicheniidites senonicus- (Ross) Skarby 1964

Cyathidites minor Couper 1953

Deltoidospora cf. D. psilostoma Rouse 1959

Tigrisporites reticulatus Singh 1971

Interulobites triangularis (Brenner) Phillips and

Felix 1971

Staplinisporites caminus (Balme) Pocock 1962 

Lycopodiumsporites sp. 

Matthesisporites tumulosus Boring 1964 

Leptolepidites verrucatus Couper 1953 

Verrucosisporites cf. V. densus (Bolkhovitina) Pocock

1970a

Cicatricosisporites sp. 

Cicatricosisporites pseudotripartitus (Bolkhovitina)

Dettmann 1963

Distaltriangulisporis perplexus (Singh) Singh 1971 

Corollina torosa (Reissinger) Cornet and Traverse

1975

Cycadopites spp. 

Equisetosporites spp. 

Araucariacites sp. 

Exesipollenites tumulus Balme 1957 

Cerebropollenites mesozoicus (Couper) Nilsson 1958 

Callialasporites segmentatus (Balme) Sukh-Dev 1961 

Vitreisporites pallidus (Reissinger) Nilsson 1958 

Pristinuspollenites sulcatus (Pierce) B. Tschudy 1973 

Clavatipollenites hughesii (Couper) Kemp 1968 

Paleoconiferus asaccatus Bolkhovitina 1956

Pityosporites cf. P. divulgatus (Bolkhovitina) Pocock

1970b

Alisporites grandis (Cookson) Dettmann 1963 

Pityosporites nigraeformis (Bolkhovitina) Pocock

1970b

Cedripites cf. C. canadensis Pocock 1962 

Cedripites cretaceus Pocock 1962 

Podocarpidites ornatus Pocock 1962 

Podocarpidites cf. P. ellipticus Cookson 1947 

Podocarpidites cf. P. multesimus (Bolkhovitina)

Pocock 1962

Podocarpidites radiatus Brenner 1963 

Burro Canyon taxa are shown on plates 5-9

The chief distinction between the assemblages from 

the upper and lower horizons of the Burro Canyon is 

that many species and specimens of Cicatricosisporites 

were found in the upper horizon assemblages and very 

few Cicatricosisporites specimens were found in the 

lower horizon assemblages.

AGE OF THE UPPER PART OF THE 

BURRO CANYON FORMATION

Both upper and lower horizon assemblages were from 

the upper part of the Burro Canyon Formation, so for 

the purpose of this discussion they will be considered 

as a unit even though the discrepancies in recovery may 

appear significant. These discrepancies may be due in 

part to variations in biofacies existing at the times of 

deposition, giving rise to the distinctly different organic 

content of the two groups of samples. It may also be 

due, in part, to the low frequency of recovery of individual taxa. With the exception of bisaccate conifer pollen and Corollina, many of the remaining taxa were 

found only as single specimens, or generally as only 

a few specimens of any single taxon.

Bisaccate conifer pollen is difficult to segregate into 

generic units. Futhermore, most genera and species are 

long-ranging and are of little value in age determinations. Corollina pollen is almost omnipresent in Upper 

Jurassic and Lower Cretaceous continental 

palynomorph-bearing rocks of North America. Consequently the remaining taxa, even though present in 

extremely low frequency in the samples, are the significant taxa for the estimation of the ages of the samples.

The palynomorphs recovered failed to reveal even a 

single specimen of tricolpate pollen. The apparent first 

record of tricolpate (tricolporate) pollen is from the Berriasian-Valanginian of the Netherlands (Burger, 1966). 

But well-documented tricolpates first appear in the 

Aptian-Albian worldwide (Doyle, 1969; Muller, 1970; 

Chlonova, 1977). In North America, tricolpates enter 

the stratigraphic record no earlier than mid-Albian time
16 PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

97

Lithology Thickness, in 

centimeters

Limestone, grey, blocky 40

Shale, black, hard, calcareous

Limestone, black

Shale, black, hard, calcareous 14

Limestone, grey

Shale, dark-grey, hard

Thin bentonite layers are 

represented by dark bands

18

Shale, black, friable; small 

calcite crystals

Shale, grey to black, hard, 

calcareous

23

Shale, black- to green-weathering 

calcareous 12

Shale, green-weathering, calcareous

80

- 60

 40

- 20

- 0

TYPE OF PALYNOMORPH 

M Corollina ;X Trilete spores Other

FIGURE 8. Gross palynomorph recovery from selected intervals in lower horizon Burro Canyon. A-F, Intervals from which samples (D-numbers) were taken. Samples from intervals A and B were barren of palynomorphs. Numbers at top of bars indicate percentage of 

each type of palynomorph.

(Singh, 1975). Consequently, palynomorph assemblages 

lacking tricolpate pollen may be assumed to be no 

younger than mid-Albian.

Because of the purported interfingering of the Jurassic Brushy Basin Member of the Morrison with the 

lower part of the Burro Canyon Formation, comparisons of Burro Canyon assemblages with Jurassic and 

early Early Cretaceous assemblages were made. The

Burro Canyon palynomorph assemblages are distinctly 

more advanced than are Late Jurassic assemblages 

from the Colorado Plateau, or from Western Canada 

(Pocock, 1962; 1970a,b). For example, two species of 

Appendicisporites were isolated from the Burro Canyon 

Formation. This taxon is not present in the Jurassic; 

it first appears worldwide in the Valanginian (Pocock, 

1967; Vakhrameev and others, 1973). Further, many
PALYNOLOGICAL ANALYSIS-BURRO CANYON FORMATION 17

species of Cicatricosisporites are present in the Burro 

Canyon, and although a few species have been reported 

from the Upper Jurassic of Europe and Asia, none have 

been found in the Jurassic of western Canada (Pocock, 

1970a), nor have we found any specimens of Cicatricosisporites in any of the assemblages from the 

Brushy Basin, Westwater Canyon, or Recapture Members of the Morrison Formation (Upper Jurassic) of the 

Colorado Plateau region. Consequently, it is safe to assume that the age of the Burro Canyon Formation is 

Neocomian to early Albian.

Assemblages from near the Jurassic-Cretaceous 

boundary in northwest Europe (Boring, 1965; Burger, 

1966; Norris, 1969; Dorhofer and Norris, 1977; 

Dorhofer, 1977) were compared with those from the 

Burro Canyon Formation. Little similarity was evident. 

In fact, little similarity between assemblages of similar 

age from England and from continental northwest 

Europe was evident. "Of the 109 trilete spore types 

described by Boring (1965) from the German JurassicCretaceous sediments, only about 10 species are known 

in the southern England succession" (Norris, 1973, p. 

99). Furthermore, the assemblage from the German 

Biickeberg Formation (Dorhofer, 1977) (BerriasianValanginian) correlative with the English upper Purbeck and lower Wealden (Dorhofer and Norris, 1977) 

yielded no bisaccate conifer pollen. Most other Neocomian assemblages yielded significant proportions of 

bisaccate pollen. Consequently, the differing biofacies 

conditions in the two European localities and in the 

Burro Canyon Formation make comparisons more difficult.

The precise position of Lower Cretaceous samples 

cited in the literature is often not known. Reports refer 

in general terms to Lower Cretaceous, or to Neocomian 

rather than to the formal subdivisions. This usage is 

true of most reports from Australia and Russia. For 

example, Burger (1973) and Dettmann (1963) referred 

to the Lower Cretaceous or Neocomian, and OrlovaTurchina (1966) reported on the Hauterivian-Barremian 

Russian complexes in general terms only.

Another fact that hinders direct correlation is the 

yield of palynomorphs from the Burro Canyon Formation. The yield of taxa of potential usefulness was minimal. Aside from conifer pollen mostly long-ranging 

species and Corollina, the remainder of the assemblage 

as a whole was sparse (see fig. 6). Generally, only a 

few specimens of any one taxon were found. Many of 

the genera and species commonly used to subdivide the 

Neocomian in other regions failed to appear in Burro 

Canyon samples. These genera include Concavissimisporites, Trilobosporites, Impardecispora, Contignisporites, Januasporites, and Schizosporis.

Comparison of the Burro Canyon assemblages with

Jurassic and Early Cretaceous assemblages from western Canada failed to present evidence for direct correlation. This lack of evidence may be due to the fact that 

the Lower Cretaceous rocks of western Canada are 

commonly no older than Barremian (Singh, 1971). Only 

one report of upper Neocomian palynomorph assemblages from Canada is available. Hopkins (1971) reported an assemblage from the Isachsen Formation, 

bounded below by upper Valanginian rocks and above 

by Albian rocks. Hopkins (1971, p. 110) concluded that 

"The Isachsen Formation is therefore entirely Lower 

Cretaceous, ranging from Upper Valanginian, including 

probably Hauterivian and Barremian; possibly also Aptian***". Hopkins also observed "There appears to be 

no significant variation of the flora from the top to bottom of the Isachsen Formation suggesting that environmental conditions did not vary greatly during the time 

represented by Isachsen deposition, ***the flora is remarkably uniform over a comparatively long period of 

time (about 10 million years)." The palynomorph assemblage from the Isachsen Formation bears the 

closest resemblance to assemblages from the Burro 

Canyon Formation yet observed, even though most of 

the species mentioned did not appear in the Burro Canyon assemblages.

Adequate data are not yet available representing the 

age-ranges of taxa found in the Burro Canyon Formation owing to the comparatively few reliable reports 

on Lower Cretaceous rocks, particularly from North 

America. The currently known ranges of all species figured on plates 5-9 are recorded in table 2.

As shown on table 2, many of the identified species 

have long ranges, and offer no aid in narrowing down 

the age of the Burro Canyon Formation. Some of the 

other species, Verrucosisporites densus (Bolkhovitina) 

Pocock, Matthesisporites tumulosus Doring, Callialasporites segmentatus (Balme) Sukh-Dev, Paleoconiferus 

asaccatus Bolkhovitina, and Cadargasporites reticulatus de Jersey and Paten are limited, as understood at present, to the Jurassic. Cicatricosisporites 

apiteretus Phillips and Felix, is limited to the Cenomanian. The ranges of the Jurassic species in our samples 

possibly may be attributed to redeposition into Lower 

Cretaceous rocks, although no visual difference in the 

appearance of the fossils was observed. On the other 

hand, both the limited ranges of the Jurassic and 

Cenomanian species may be due to the limited amount 

of work that has been done on Lower Cretaceous rocks 

in North America. The true ranges may not yet be evident. For example, the genus Cadargasporites and the 

species Cadargasporites reticulatus de Jersey and 

Paten, have been reported previously, to our knowledge, only from the Early Jurassic of the Surat Basin, 

Australia (de Jersey and Paten, 1964). Yet the two
18 PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

TABLE 2. Stratigraphic ranges of Burro Canyon palynomorph species

atfiinhfini lrfl>P« sonnniVtis (Rr>R R ) SVarb"

JURASSIC

 

EARLY CRETACEOUS

NEOCOMIAN

BERRIASIAN

VALANGINIAN

HAUTERIVIAN

BARREMIAN APTIAN

?

ALBIAN

 

 

LATE

CRETACEOUS

specimens from the Burro Canyon Formation with their 

distinctive distal labyrinthine reticulum, and smooth 

proximal contact area, appear to be conspecific with the 

Australian species.

The data presented on table 2 suggest to us a late 

Neocomian to Aptian-Albian age. A few taxa from table 

2 merit further discussion.

Tigrisporites reticulatus Singh. This species was 

first reported by Singh (1971) from the middle Albian 

of Alberta, Canada. Its presently known range is from 

the mid-Albian to early Cenomanian. Although several 

specimens of this species were found, the species was

not represented in all preparations. This species is not 

as yet known from anywhere in the world except from 

western North America. A closely allied species, Tigrisporites scurrandus Morris with an almost identical 

known range (mid- and late Albian) also appears to be 

confined to western North America. We have found 

both species in formations of Albian Age from Colorado 

and Idaho.

Interulobites triangularis (Brenner) Phillips and 

Felix. This species was observed sporadically in Burro 

Canyon assemblages. It has been reported previously 

only by Brenner (1963) (as Lycopodiacidites trian-
PALYNOLOGICAL ANALYSIS BURRO CANYON FORMATION 19

gularis) from the Albian-Aptian, possibly Barremian, 

Patapsco, Arundel and Patuxent Formations of Maryland, by Phillips and Felix (1971) from the Albian 

Paluxy Formation of Louisiana, and by Scott (1976) 

from the Neocomian(?) Sundays River and Kirkwood 

Formations of South Africa.

Appendicisporites jansonii Pocock. The range of 

this species according to Singh (1971) is Barremian to 

Albian. Outside of Canada it has been reported by Hedlund and Morris (1968) from the -Albian of Oklahoma. 

Singh (1971) claimed that Appendicisporites sp. reported by Lantz (1958) from the Albian of England is 

conspecific with A. jansonii Pocock. The presence of 

Appendicisporites species suggests that the age of the 

Burro Canyon samples can be no older than Valanginian. "It is important to note the appearance, in the Valanginian of the genus Appendicisporites also. This 

genus is unknown in older deposits of Europe and 

Asia." (Vakrameev and others, 1973 p. 214). "No 

species of this genus have been recorded from strata 

older than this [Valanginian] anywhere in the world." 

(Pocock, 1967 p. 135).

Clavatipollenites hughesii (Couper) Kemp. A single 

specimen of Clavatipollenites hughesii (Couper) Kemp 

was found on one of the slides of a sample from the 

lower horizon. Although literature reports of Triassic 

and Jurassic occurrences from several parts of the 

world have appeared (see previous discussion), this 

species has not been reported from North American 

rocks older than Barremian and from western North 

American rocks older than Albian (Singh, 1975). Its earlier appearance elsewhere may mean that the parent 

plant had not migrated to North America earlier, or 

palynological investigations have not yet uncovered the 

data. The plant may have existed for a long time in 

extremely low frequency and in limited ecological environments, before it expanded its habitat and abundance 

sufficiently to be represented commonly in Albian and 

younger rocks.

The taxa discussed, combined with the absence of 

tricolpate pollen all point to an Aptian-early Albian age, 

with the remote possiblity of a late Barremian age, for 

the upper part of the Burro Canyon Formation.

CONCLUSIONS

Although all students of these beds are agreed that 

Burro Canyon and Cedar Mountain beds are physically 

continuous in large part, the results of the present 

study of palynomorphs shows a difference in age: the 

upper part of the Cedar Mountain is younger (late or 

latest Albian) than the upper part of the Burro Canyon 

(Aptian to early Albian and perhaps as old as Barremian). We suggest that the thick lower part of the 

Cedar Mountain, which is undated by fossils, may contain beds that are age equivalent to the older Burro 

Canyon beds. The beds equivalent to the uppermost 

Cedar Mountain beds of late or latest Albian age may 

have been removed by pre-Dakota (pre-earliest Late 

Cretaceous) erosion at the Burro Canyon locality or are 

represented in the 6 m of green mudstones (nonproductive of palynomorphs) at the top of the Burro Canyon 

at the collection locality. A further speculation that may 

be warranted is that the Neocomian (early Early Cretaceous) may be represented in a still-undated lower part 

of the Burro Canyon and Cedar Mountain perhaps 

even including an upper part of the Brushy Basin Member of the Morrison. The recognition of a fossil 

(Clavatipollenites hughesii (Couper) Kemp) known to 

occur as early as the Barremian (latest Neocomian) 

suggests that the undated older beds of these formations might contain beds of this age, a stage that is 

almost unrecorded in western North America.

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Moscow, p. 97-100.

Norris, Geoffrey, Jarzen, D. M., and Awai-Thorne, Beatrice, V., 

1975, Evolution of the Cretaceous terrestrial palynoflora in western Canada; in Caldwell, W.G.E., The Cretaceous System in the 

Western Interior of North America; Geological Society of Canada 

Special Paper 13, p. 333-364.

Orlova-Turchina, G. A., 1966, Hauterivian-Barremian spore complexes of the west and central parts of the Crimea Plain: Paleontological Symposium Canada Department of the Secretary of 

State Translation Bureau, v. 1, no. 3, p. 90-96.

Pannella, Georgio, 1966, Palynology of the Dakota Group and 

Graneros Shale of the Denver basin: Boulder, Co., University 

of Colorado, Ph.D. Thesis, 173 p.

Phillips, P. P., and Felix, C. J., 1971, A study of Lower and Middle 

Cretaceous spores and pollen from the southeastern United 

States. I. Spores: Pollen et Spores, v. 13, no. 2, p. 279-348.

Pocock, S.A.J., 1962, Microfloral analysis and age determination of 

strata at the Jurassic-Cretaceous boundary in the western 

Canada plains: Palaeontographica, v. Ill, sec. B, nos. 1-3, p. 

1-95.

 1967, The Jurassic-Cretaceous boundary in northern Canada: 

Review of Palaeobotany and Palynology, v. 5, p. 129-136.

 1970a, Palynology of the Jurassic Sediments of western 

Canada. Part 1. Terrestrial Species: Palaeontographica sec. B.,v. 

130, no. 1-2, p. 1-72.

 1970b, Part 1 (Continued) Terrestrial species: Palaeontographica sec. B., v. 130, no. 3-6, p. 73-136. 

-1972 Part 2. Marine species: Palaeontographica sec. B., v. 137,

no. 4-6, p. 85-153. 

Saucier, A. E., 1974, Stratigraphy and uranium potential of the Burro 

Canyon Formation in the southern Chama Basin, New Mexico: 

in Guidebook of central-northern New Mexico, New Mexico 

Geological Society 25th Field Conference, p. 211-217.

Scott, L., 1976, Palynology of Lower Cretaceous deposits from the

Algoa Basin (Republic of South Africa): Pollen et Spores, v. 18,

no. 4, p. 563-609. 

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15, p. 1-238. 

 1971, Lower Cretaceous microfloras of the Peace River area,

northwestern Alberta: Research Council of Alberta Bulletin 28,

v. 1,299 p. 

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the Mid-Cretaceous strata of Alberta; in Caldwell, W.G.E., The 

Cretaceous System in the Western Interior of North America; 

Geological Society of Canada Special Paper 13, p. 365-389.

Stokes, W. L., 1944, Morrison formation and related deposits in and 

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Map 93.
PALYNOLOGICAL ANALYSIS BURRO CANYON FORMATION 21

Thayn, G. F., 1973, Three new species of petrified dicotyledonous 

wood from the Lower Cretaceous Cedar Mountain Formation of 

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Botany and Range Science, 43 p.

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Memoir 86, p. 213-220.

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194.

INDEX

Page

Age ............................................... 1, 7, 10, 11, 19

albertensis, Nyssapollenites ............................ 10, 11

Algae ................................................................ 13

Alisporites grandis ..................... 9, 12, 15; pis. 3, 8

thomasii ............................................ 13; pi. 8

aliquantulus, Tricolporopollenites ........................ 10

apiteretus, Cicatricosisporites ..................... 13; pi. 6

Appendicisporites bilateralis ....................... 13; pi. 6

jansonii ........................................ 13, 19; pi. 6

sp. ......................................................... 16, 19

Araucariacites sp. ............................... 13, 15; pi. 7

Arundel Formation of Maryland .......................... 19

asaccatus, Paleoconiferus ....................... 15, 17; pi.8

asinaria, Nipponaia ........................................... 11

Aspen Shale ........................................................ 7

asteroides, Asteropollis ................................ 9; pi. 4

Asteropollis asteroides ................................. 9; pi. 4

augustus, Cicatricosisporites ...................... 13; pi. 6

australis, Cyathidites .................................. 8; pi. 1

B

Baculatisporites comaumensis ...................... 8; pi. 1

belfordii, Laevigatosporites ........................... 8; pi. 1

Benton Formation .............................................. 10

bilateralis, Appendicisporites ...................... 13; pi. 6

Botryococcus ...................................................... 13

Brushy Basin Member of the Morrison

Formation ...... 1, 11, 16, 17

Buckeberg Formation ......................................... 17

Buckhorn Conglomerate Member ........................... 2

Cadargasporites ...............................................

reticulatus ..................................... 13, 17;

Calcite ............................................................

Callialasporites segmentatus ................. 15, 17;

sp. ..................................................... 13;

canadensis, Cedripites ................ 9, 13, 15; pis.

carpentieri, Cycadopites ..........................

Castle Dale, Utah ............................................

Cedripites canadensis ................. 9, 13, 15; pis.

cretaceus ............................. 9, 13, 15; pis.

Cerebropollenites mesozoicus ...................... 15;

Charophyte ......................................................

Cheirolepis ......................................................

Cicatricosisporites apiteretus ................. 13, 17;

augustus ............................................ 13;

crassistriatus ...................................... 13;

cuneiformis ........................................ 13;

hughesii ............................................... 8;

mediastriatus ...................................... 13;

minor ............................................. 13;

minutaestriatus ..................................... 8;

phaseolus ........................................... 13;

potomacensis ...................................... 13;

pseudotripartitus ............................ 13, 15;

subrotundas ......................................... 13;

venustus ............................................... 9;

sp. ................................ 8, 13, 15, 17; pis.

circumundulatus, Psilatriletes ...................... 9;

Clavatipollenites hughesii............ 9, 15, 19; pis.

sp. ............................................................

Clavator harrisi ...............................................

Cloverly Formation ..........................................

comaumensis, Baculatisporites ..................... 8;

Concavissimisporites .........................................

pwnctatus ............................................. 8;

variverrucatus ....................................... 8;

.. 17

pi. 5

.. 11

pi. 7

pi. 7

3, 8

'; pi-4

..... 7

3, 8

3, 8

pi. 7

.... 7

.. 15

pi. 6

pi. 6

pi. 6

pi. 6

pi. 2

pi. 6

pi. 6

pi. 2

pi. 5

pi. 6

pi. 6

pi 6

pi. 2

2, 6

pi. 2

4, 7

.... 9

.... 7

4, 7

pi. 1

.. 17

pi. 1

pi. 1

Contignisporites ................................................. 17

Converrucosisporites proxigranulatus .......... 13; pi. 5

Corollina ............................................ 7, 14, 15, 17

torosa ................................. 9, 13, 15; pis. 4, 7

Costatoperforosporitessp. .............................. 9; pi. 2

Cottonwood Creek ................................................ 6

crassimurus, Tricolpites .............................. 9; pi. 4

crassistriatus, Cicatricosisporites ................ 13; pi. 6

cretaceus, Cedripites ................... 9, 13, 15; pis. 3, 8

cuminus, Staplitiisporites ...................... 13, 15; pi. 5

cuneiformis, Cicatricosisporites ................... 13; pi. 6

Cupwliferoidaepollenites minutus .................. 9; pi. 4

parvulus .............................................. 9; pi. 4

Cyathidites australis ................................... 8; pi. 1

minor ................................. 8, 13, 15; pis. 1, 5

Cycadopites carpentieri ................................ 9; pi. 4

spp. .............................................. 15; pis. 4, 7

D

Dakota Group ................................................ 4, 10

Dakota Sandstone ..................................... 1, 10, 11

dakotensis, Tricoloporites .................................... 10

Deltoidpspora hallii ..................................... 8; pi. 1

psilostoma .......................................... 15; pi. 5

Densoisporites micronigulatus ...................... 9; pi. 2

velatus ................................................. 9; pi. 2

densus, Verrucosisporites ...................... 15, 17; pi. 5

Dictyotriletes granulatus .............................. 8; pi. 1

pseudoreticulatus ................................. 13; pi. 5

Disappointment Creek ...................................... , 6

Distaltriangulisporites irregularis ................. 9; pi. 2

perplexus ........................................... 15; pi. 6

sp. .......................................................... 13; pi. 6

Distribution ......................................................... 4

divulgatus, Pityosporites ............................ 15; pi. 8

douglassi, Protelliptio ......................................... 11

E

Echinatisporis varispinosus .......................... 8; pi. 2

ellipticus, Podocarpidites ........................... 15; pi. 9

Equisetosporites spp. .......................... 13, 15; pi. 7

Eucommiidites sp. ..................................... 9; pi. 4

Eupera onestae .................................................... 7

Exesipollenites tumulus .................... 9, 15; pis. 4, 7

farri, "Unio" ..................................................... 11

Ferron, Utah ....................................................... 7

Foraminisporis wonthaggiensis ..................... 8; pi. 1

sp. ....................................................... 8; pi. 1

fossulatus, Undulatisporites ................................ 13

Four Corners ...................................................... 4

Frenelopsis varians ............................................ 11

Gannett Group ..................................................... 7

georgensis, Rousea ...................................... 9; pi. 4

Ginkgocycadophytus nitidus ......................... 9; pi. 4

Gleicheniidites senonicus ................... 8, 15; pis. 1, 5

gracilis, Laevigatosporites ............................ 8; pi. 1

grandis, Alisporites .................... 9, 13, 15; pis. 3, 8

granulatus, Dictyotriletes ............................. 8; pi. 1

Pityosporites ......................................... 9; pi. 3

Great Artesian Basin ......................................... 10

Green River Formation ...................................... 11

hallii, Deltoidospora .................................... 8; pi. 1

Hamm Canyon quadrangle ................................ 6, 7

harrisi, Clavator ................................................ 7

Henry Mountains ................................................. 4

hiatus, Taxodiaceaepollenites ........................ 9; pi. 4

hughesii, Cicatricosisporites ......................... 8; pi. 2

Clavatipollenites ......................... 9, 15, 19; pis. 4, 7

Huntsman Shale ................................................. 10

I

Icacinoxylon ........................................................ 7

Illite-smeetite ..................................................... 11

Impardecispora .................................................. 17

Interulobites triangularis ...................... 15, 18; pi. 5

irregularis, Distaltriangulisporites .............. 9; pi. 2

Isaehsen Formation ............................................ 17

J, K

jansonii, Appendicisporites ................. 13, 19; pi. 6

Januasporites .................................................... 17

Kassler Sandstone Member of the South Platte

Formation ..................... 10

Kirkwood Formation of South Africa ................... 19

Kootenai Formation .............................................. 7

Laevigatosporites belfordii ............................ 8

gracilis ................................................ 8

Leptolepidites verrucatus ............................ 15

sp. ....................................................... 8

Liliacidites ................................................

peroreticulatus ...................................... 9

sp. ....................................................... 9

Loon River Formation ...................................

pi. 1

pi. 1

pi. 5

pi. 1

..... 1

pi. 4

pi. 4

... 10

Lycopodiacidites triangularis ............................... 18

Lycopodiumsporitessp. ...................... 8, 15; pis. 1, 5

Lytle Formation of Dakota Group ......................... 4

Lytle Sandstone Member of Purgatoire Formation .. 4

M

Mannville Group ................................................ 10

Mattesisporites tumulosus ............... 13, 15, 17; pi. 5

mediostriatus, Cicatricosisporites ................ 13; pi. 6

mesozoicus, Cerebropollenites ..................... 15; pi. 7

micromunus, Tricolpites .............................. 9; pi. 4

microrugulatus, Densoisporites ..................... 9; pi. 2

minisculus, Podocarpidites ........................... 9; pi. 3

minor, Cicatricosisporites .......................... 13; pi. 6

Cyathidites .......................... 8, 13, 15; pis. 1, 5

Tempskya ...................................................... 1

Todisporites ............................... 8, 13; pis. 1, 5

minutaestriatus, Cicatricosisporites ............... 8; pi. 2

minutus, Cupuliferoidaepollenites ................. 9; pi. 4

Monocolpopollenitessp. ................................. 9; pi. 4

Morrison Formation ............................. 1, 11, 16, 17

Mowry Shale ..................................................... 10

multesimus, Podocarpidites ............... 9, 15; pis. 3, 9

multicostatus, Equisetosporites ..................... 9; pi. 4

N, 0

nigraeformis, Pityosporites ................ 9, 15; pis. 3, 8

Nipponaia asinaria ............................................ 11

nitidus, Ginkgocycadophytus ........................ 9; pi. 4

Nyssapollenites albertensis ............................. 10, 11

23
24 PALYNOLOGICAL EVALUATION OF CEDAR MOUNTAIN AND BURRO CANYON FORMATIONS

Page 

onestae, Eupera ................................................... 7

ornatm, Podocarpidites ........................ 13, 15; pi. 9

Otway Basin ...................................................... 10

Paleoconiferus asaccatus .........:............. 15, 17;

pallidus, Vitreisporites ............... 9, 13, 15; pis.

Paluxy Formation of Louisiana .........................

paraneus, Striatopollis ................................ 9;

Paraphyllanthoxylon ........................................

parvulus, Cupuliferoidaepollenites ................ 9;

Patapsco Formation of Maryland .......................

Patuxent Formation of Maryland .......................

Peace River ....................................................

peroreticulatus, Liliacidites .......................... 9;

perplexus, Distaltriangulisporites ................ 15;

pkaseolus, Cicatricosisporites ..................... 13;

Pilosisporites trichopapillosus ....................... 8;

Pityosporites divulgatus ............................. 15;

granulatus ............................................ 9;

nigraeformis .............................. 9, 15; pis.

Podocarpidites ellipticus ............................ 15;

minisculus ........................................... 9;

multisimus ................................ 9, 15; pis.

ornatus ......................................... 13, 15;

radiatus ............................................. 15;

sp. ....................................................... 9;

potomacensis, Cicatricosisporites ................. 13;

Pristinuspollenites sulcatus ............... 9, 15; pis.

Protelliptio douglassi ........................................

proxigranulatus, Converrucosisporites ......... 13;

pseudoreticulatus, Dictyotriletes .................. 13;

pseudotripartitus, Cicatricosisporites ...... 13, 15;

Psilatriletes circumundulatus ....................... 9;

psilostoma, Deltoidospora .......................... 15;

pulcher, Tetracolpites ............................ 9, 10;

punctatus, Concavissimisporites .................... 8;

Purbeck Formation ...........................................

Purgatoire Formation .......................................

pi. 8

3, 7 

.. 19 

pi. 4 

.... 7 

pi. 4 

.. 19 

.. 19 

.. 10 

pi. 4 

pi. 6 

pi. 5 

pi. 2 

pi. 8 

pi. 3

3, 8 

pi. 9 

pi. 3

3, 9 

pi. 9 

pi. 9 

pi. 3 

pi. 6

3, 7 

.. 11 

pi. 5 

pi. 5 

pi. 6 

pi. 2 

pi. 5 

pi. 4 

pi. 1 

.. 17 

.... 4

Q,R

Quartz .............................................................. 11

radiatus, Podocarpidites ............................ 15; pi. 9

Racapture Member of the Morrison Formation ..... 17

Red Branch Member of the Woodbine Formation . 10 

reticulatus, Cadargasporites ................... 13, 7; pi. 5

Tigrisporites .................................. 15, 18; pi. 5

Retitricolpites vermimurus ........................... 9; pi- 4

virgeus ................................................. 9; pi. 4

vulgaris ............................................... 9; pi. 4

Rock Canyon Creek ............................................. 6

Rousea georgensis ....................................... 9; pi. 4

S

Sampling methods ................................................ 4

Schizosporis ....................................................... 17

sp. ....................................................... 9; pi. 2

scurrandus, Tigrisporites .................................... 18

segmentatus, Callialasporites ................ 15, 17; pi. 7

senonicus, Gleicheniidites .................. 8, 15; pis. 1, 5

Shaftesbury Formation of Alberta ....................... 10

Slick Rock, Colo. ................................................. 6

South Platte Formation ...................................... 10

Staplinisporites caminus ....................... 13, 15; pi. 5

Stokes-Katich locality ....................................... 6, 7

Striatopollis paraneus ................................. 9; pi. 4

subrotundas, Cicatricosisporites .................. 13; pi. 6

sulcatus, Pristinuspollenites .............. 9, 15; pis. 3, 7

Sundays River Formation of South Africa ........... 19

Surat Basin, Australia ........................................ 17

Taxodiaceaepollenites hiatus ......................... 9; pi. 4

Tempskya minor .................................................. 7

Tetracolpites pulcher ............................. 9, 10; pi. 4

sp. ....................................................... 9; pl. 4

thomasii, Alisporites ................................. 13; pl. 8

Tigrisporites reticulatus ........................ 15; 18; pl. 5

scurrandus .................................................. 18

Todisporites minor ........................... 8, 13; pis. 1, 5

sp. ....................................................... 8; pl. 1

torosa, Corollina ....................... 9, 13, 15; pis. 4, 7

triangularis, Interulobites ..................... 15, 18; pl. 5

Lycopodiacidites ................................................. 19

trichopapillosus, Pilosisporites ...................... 8; pl. 2

Tricolpites crassimurus ............................... 9; pl. 4

micromunus ............................................... 9; pl. 4

urilsonii ................................................ 9; pl. 4

sp. 1 ................................................... 9; pl. 4

Tricolporites dakotensis ...................................... 10

Tricolporopollenites aliquantulus ......................... 10

Trilobosporites ................................................... 17

Trinity Group of the Gulf Coast ........................... 7

tumulosus, Matthesisporites ............ 13, 15, 17; pl. 5

tumulus, Exesipollenites ................... 9, 15; pis. 4, 7

U, V, W

Undulatisporites fossulatus ........................ 13; pl. 5

"Unio" farri ...................................................... 11

varians, Frenelopsis ........................................... 11

varispinosus, Echinatisporis ......................... 8; pl. 2

varivermcatus, Concavissimisporites ............. 8; pl. 1

velatus, Densoisporites ................................ 9; pl. 2

venustus, Cicatricosisporites ......................... 9; pl. 2

vermimurus, Retitricolpites .......................... 9; pl. 4

verrucatus, Leptolepidites ........................... 15; pl. 5

Verrucosisporites densus ....................... 15, 17; pl. 5

virgeus, Retitricolpites ................................. 9; pl. 4

Vitreisporites pallidus ................ 9, 13, 15; pis. 3, 7

vulgaris, Retitricolpites ................................ 9; pl. 4

Wealden Formation ............................................ 17

Westwater Canyon Member of the Morrison

Formation ..................... 17

wonthaggiensis, Foraminisporis .................... 8; pl. 1

Woodbine Formation of Oklahoma ....................... 10

U.S GOVERNMENT PRINTING OFFICE: 1984 776-041/4024 REGION NO 8
PLATES 1-9
PLATE 1 

Cedar Mountain Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers (text fig. 2)]

FIGURE 1. Laevigatosporites cf. L. belfordii Burger 1976

Sample D5785-A, prep. 4, floated first, fines, slide 3, coordinates 99.0x21.6.

2. Laemgatosporites gracilis Wilson and Webster 1946 

Sample D5785, slide 1, coordinates 81.Ox 13.7.

3. Cyathidites australis Couper 1953

Sample D5785-A, prep. 4, floated first, hvs, slide 5, coordinates 112.5x8.2.

4. Todisporites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 89.3x 14.8.

5. Todisporites minor Couper 1958

Sample D5785-A, prep. 4, floated first, fines, slide 3, coordinates 106.2x6.7.

6. Gleicfieniidites senonicus Ross 1949

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 100.8x17.3.

7. Lygodiumsporites sp.

Sample D5785, slide 2, coordinates 76.7x10.1.

8. Deltoidospora hallii Miner 1935

Sample D5785-A, prep. 2, slide 1, coordinates 91.6x6.0.

9. Cyathidites minor Couper 1953

Sample D5785-A, prep. 4, floated first, fines, slide 3, coordinates 101.6x2.0.

10. Concavissimisporites variverrucatus (Couper) Singh 1964

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 110.2x18.4.

11. Foraminisporis sp.

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 96.8x6.7.

12. Concavissimisporites variverrucatus (Couper) Singh 1964

Sample D5785-A, prep. 4, floated first, hvs, slide 6, coordinates 112.5x8.2.

13. Dictyotriletes granulatus Pocock 1962

Sample D5785-A, prep. 4, floated first, fines, slide 1, coordinates 97.4x21.1.

14. Foraminisporis cf. F. wonthaggiensis (Cookson and Dettmann) Dettmann 1963 

Sample D5785-A, prep. 2, slide 1, coordinates 112.1x19.8.

15. Concavissimisporites punctatus (Delcourt and Sprumont) Brenner 1963

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 81.9x3.1.

16. Trilete spore undetermined.

Sample D5785-A, prep. 2, slide 1, coordinates 104.2x10.4. Ornamented with short blunt verrucae as well as short spines.

17. Leptolepidites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 87.6x5.1.

18. Baculatisporites comaumensis (Cookson) Potonie 1956

Sample D5785-A, prep. 2, slide 1, coordinates 110.5x11.1.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 1

V ' 18

LAEVIGATOSPORITES, CYATHIDITES, TODISPORITES. GLEICHENIIDITES. LYGODIUMSPORITES, 

DELTOIDOSPORA, CONCAVISSIMISPORITES, FORAMINISPORIS, TRILETE SPORE, 

LEPTOLEPIDITES, AND BACULATISPORITES
PLATE 2 

Cedar Mountain Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers (text fig. 2)]

FIGURE 1. Pilosisporites trichopapillosus (Thiergart) Delcourt and Sprumont 1955

Sample D5785-A, prep. 4, floated first, fines, slide 1, coordinates 77.7x5.4. 

2-4. Echinatisporis varispinosus (Pocock) Srivastava 1975

2. Sample D5785-A, prep.4, floated first, fines, slide 2, coordinates 87.3x5.9.

3. Sample D5785-A, prep. 4, floated first, fines, slide 3, coordinates 73.9x13.0.

4. Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 107.6x4.8.

5. Cicatricosisporites hughesii Dettmann 1963

Sample D5785-A, prep. 4, floated first, fines, slide 3, coordinates 108.4x13.3.

6. Cicatricosisporites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 74.0x7.5.

7. Cicatricosisporites cf. C. minutaestriatus (Bolkhovitina) Pocock 1964.

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 98.6x9.9.

8. Cicatricosisporites venustus Deak 1963

Sample D5785-A, prep. 2, slide 1, coordinates 110.0x6.2.

9. Cicatricosisporites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 95.1x21.1.

10. Distaltriangulisporites cf. D. irregularis Singh 1971

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 88,0x14.5.

11. Costatoperforosporites sp.

Sample D5785-A, prep. 4, hvs., slide 6, coordinates 76.8x8.0.

12. Trilete spore, undetermined.

Sample D5785, slide 2, coordinates 91.1x19.3.

13. Densoisporites microrugulatus Brenner 1963

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 75.^x8.0.

14. Psilatriletes circumundulatus Brenner 1963

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 84.2x20.4. 

15-16. Trilete spore, undetermined.

Sample D5785-A, prep. 2, slide 1, coordinates 90.5x19.4.

15. Proximal view.

16. Distal view.

17. Densoisporites velatus Weyland and Krieger 1953

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 83.5x12.4.

18. Undetermined.

Sample D5785-A, prep. 2, slide 1, coordinates 102.9x15.6.

19. cf. Schizosporis sp.

Sample D5785-A, prep. 4, floated first, fines, slide 1, coordinates 103.5x16.2
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 2

PILOSISPORITES, ECHINATISPORIS. CICATRICOSISPORITES, DISTALTRIANGULISPORITES. 

COSTATOPERFOROSPORITES, DENSOISPORITES, PSILATRILETES, cf. SCHIZOSPORIS,AND TRILETE SPORE
PLATE 3 

Cedar Mountain Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers (text fig. 2)]

FIGURE 1. Alisporites grandis (Cookson) Dettmann 1963

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 88.2x4.0.

2. Pityosporites granulatus Phillips and Felix 1971

Sample D5785-A, prep. 4, floated first, hvs., slide 5, coordinates 95.2x17.6.

3. Cedripites cf. C. cretaceus Pocock 1962

Sample D5785-A, prep. 4, floated first, fines, slide 1, coordinates 77.8x5.2.

4. Podocarpidites multesimus (Bolkhovitina) Pocock 1962

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 97.1x10.1.

5. Pityosporites nigraeformis (Bolkhovitina) Pocock 1970

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 83.2x22.3.

6. Pristimt^pollenites sulcatus (Pierce) B. Tschudy 1973

Sample D5785-A, prep. 4, floated first, fines, slide 1, coordinates 104.8x4.1.

7. Cedripites canadensis Pocock 1962

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 87.7x5.4.

8. Podocarpidites cf. P. minisculus Singh 1964

Sample D5785-A, prep. *, floated first, hvs., slide 5, coordinates 99.1x19.4.

9. Podocarpidites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 112.2x2.4.

10. Cedripites cf. C. canadensis Pocock 1962

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 74.8x11.9.

11. Vitreisporites pallidus (Reissinger) Nilsson 1958

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 110.3x18.0.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 3

8 -*m^ ^*ajft£:' 9

ALISPORITES, PITYOSPORITES, CEDRIPITES, PODOCARPIDITES, PRISTINUSPOLLENITES,

AND VITREISPORITES
PLATE 4 

Cedar Mountain Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany location numbers (text fig. 2)]

FIGURE 1. Cycadopites carpentieri (Del court and Sprumont) Singh 1964

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 110.9x12.1.

2. Cycadopites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 99.0x13.0.

3. Monocolpopollenites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 96.0x4.0.

4. Monocolpopollenites sp.

Sample D5785-B, slide 3, coordinates 101.6x14.2.

5. Ginkgocycadophytus cf. G. nitidus (Balme) de Jersey 1962

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 81.4x4.6.

6. Equisetosporites multicostatus (Brenner) Norris 1967 

Sample D5785-A, prep. 2, coordinates 106.1x22.5.

7. Taxodiaceaepollenites hiatus (Potonie) Kremp 1949.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 92.8x1.6.

8. Eucommiidites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 102.7x21.5.

9. Corollina torosa (Reissinger) Cornet and Traverse 1975.

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 80.7x5.7.

10. Exesipollenites tumulus Balme 1957

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 78.3x2.1. 

11-12. Asteropollis asteroides Hedlund & Norris 1968

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 104.4x9.4.

11. Low focus showing baculae near equator.

12. High focus.

13. Clavatipollenites hughesii (Couper) Kemp 1968

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 112.0x21.0.

The size of this specimen is on the borderline between C. hughesii (Couper) Kemp and C. minutus Brenner.

14. Liliacidites sp.

Sample D5785-B, prep. 2, slide 2, coordinates 112.3x14.5.

15. Liliacidites cf. L. peroreticulatus (Brenner) Singh 1971 

Sample D5785-B, slide 3, coordinates 106.5x5.7.

16. Tricolpites crassimurus (Groot and Penny) Singh 1971

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 94.1x7.5.

17. Tricolpites cf. T. crassimurus (Groot and Penny) Singh 1971

Sample D5785-A, prep. 4, floated first, Hvs., slide 5, coordinates 88.2x9.1.

18. Cupuliferoidaepollenites parvulus (Groot and Penny) Dettmann 1973

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 90.5x2.1.

19. Retitricolpites cf. R. virgeus (Groot, Penny and Groot) Brenner 1963

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 83.0x11.8.

20. Retitricolpites vulgaris Pierce 1961

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 104.3x20.0.

21. Retitricolpites vulgaris Pierce 1961

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 111.4x17.0.

22. Tricolpites cf. T. mlsonii Kimyai 1966

Sample 5785-A, prep. 4, floated first, fines, slide 4, coordinates 88.0x16.2.

23. Striatopollis paraneus (Norris) Singh 1971

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 106.4x5.4.

24. Striatopollis paraneus (Norris) Singh 1971

Sample D5785, slide 2, coordinates 105.5x13.3.

25. Retitricolpites vermimurus Brenner 1963

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 97.5x19.8.

26. Rousea georgensis (Brenner) Dettman 1973

Sample D5785-A, prep. 4, floated first, Hvs., slide 5, coordinates 112.1x11.0.

27. Cupuliferoidaepollenites minutus (Brenner) Singh 1971

Sample D5785-B, prep. 2, slide 2, coordinates 111.5x8.6.

28. Tricolpites cf. T. sp. 1 of Kemp 1968

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 104.1x14.5 

29-30. Tricolpites micromunus (Groot and Penny) Singh 1971

Sample D5785-A, prep. 4, floated first, fines, slide 2, coordinates 110.7x2.0. (Sensu Groot and Penny. This specimen is 

small and may not be the same species as figured by Singh 1971).

29. High focus.

30. Low focus.

31. Tetracolpites cf. T. pulcher Srivasteva 1969

Sample D5785-A, prep. 4, floated first, fines, slide 3, coordinates 105.5x8.0.

32. Tetracolpites sp.

Sample D5785-A, prep. 4, floated first, fines, slide 4, coordinates 89.8x17.9.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 4

20

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CYCADOPITES, MONOCOLPOPOLLENITES, GINKGOCYCADOPHYTUS, EQUISETOSPORITES,

TAXODIACEAEPOLLENITES, EUCOMMIIDITES, COROLLINA, EXESIPOLLENITES, ASTEROPOLLIS,

CLAVATIPOLLENITES, LILIACIDITES, TRICOLPITES, CUPULIFEROIDAEPOLLENITES,

RETITRICOLPITES, STRIATOPOLLIS, ROUSE A, AND TETRACOLPITES
PLATE 5 

Burro Canyon Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers, (text fig. 2)]

FIGURE 1. Gleicheniidites senonicus Ross 1949

Sample D5803, slide 22, coordinates 111.6x13.8.

2. Undulatisporites cf. U. fossulatus Singh 1971

Sample D5510-B, slide 1, coordinates 103.6x10.5.

3. Cyathidites minor Couper 1953

Sample D5510-C, slide 4, coordinates 105.9x6.8.

4. Deltoidospora cf. D. psilostoma Rouse 1959

Sample D5803, slide 12, coordinates 91.0x17.8.

5. Todisporites minor Couper 1958

Sample D5801, prep. 2, slide 4, coordinates 78.1x20.9.

6. Dictyotriletes pseudoreticulatus (Couper) Pocock 1962

Sample D5801, slide 2, coordinates 107.2x9.8. 

7-8. Tigrisporites reticulatus Singh 1971

Sample D5973, slide 2, coordinates 75.2x14.3. 

9-10. Cadargasporites reticulatus de Jersey and Paten 1964 

Sample D5510-B, slide 2, coordinates 93.8x3.0.

11. Interulobites triangularis (Brenner) Phillips and Felix 1971 

Sample D5803, slide 4, coordinates 107.6x21.7.

12. Interulobites triangularis (Brenner) Phillips and Felix 1971 

Sample D5973, slide 2, coordinates 81.2x15.6.

13. Staplinisporites caminus (Balme) Pocock 1962 

Sample D5803, slide 6, coordinates 96.4x4.4.

14. Staplinisporites caminus (Balme) Pocock 1962

Sample D5803, slide 11, coordinates 82.4x19.8.

15. Lycopodiumsporites sp.

Sample D5803, slide 22, coordinates 74.7x1.2.

16. Matthesisporites tumulosus Doring 1964

Sample D5803, slide 12, coordinates 81.7x21.1.

17. Leptolepidites cf. L. verrucatus Couper 1953

Sample D5803, slide 8, coordinates 90.0x2.2.

18. aff. Cicatricososporites phaseolus (Delcourt and Sprumont) Krutzsch 1959 

Sample D5801, slide 2, coordinates 76.0x15.5.

19. Converrucosisporites cf. C. proxigranulatus Brenner 1963 

Sample D5510-C, slide 2, coordinates 98.4x15.4.

20. Verrucosisporites densus (Bolkhovitina) Pocock 1970 

Sample D5803, slide 6, coordinates 106.1x4.7.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 5

20

GLEICHENIIDITES, UNDULATISPORITES, CYATHIDITES, DELTOIDOSPORA, TODISPORITES, 

DICTYOTRILETES, TIGRISPORITES, CADARGASPORITES, INTERULOBITES, STAPLINISPORITES, 

LYCOPODIUMSPORITES, MATTHESISPORITES, LEPTOLEPIDITES, CICATRICOSOSPORITES, 

CONVERRUCOSISPORITES, AND VERRUCOSISPORITES
PLATE 6 

Burro Canyon Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers, (text fig. 2)]

FIGURE 1. Cicatricosisporites cf. C. minor (Bolkhovitina) Pocock 1964 

Sample D5510-C, slide 1, coordinates 109.4x11.1.

2. Cicatricosisporites cf. C. cuneiformis Pocock 1964 

Sample D5510-C, slide 4, coordinates 100.3x10.0.

3. Cicatricosisporites augustus Singh 1971

Sample D5510-B, slide 1, coordinates 99.0x4.5.

4. Cicatricosisporites cf. C. potomacensis Brenner 1963 

Sample D5510-C, slide 2, coordinates 87.0x5.5.

5. Cicatricosisporites cf. C. mediostriatus (Bolkhovitina) Pocock 1964 

Sample D5510-C, slide 1, coordinates 88.8x5.4.

6. Cicatricosisporites sp.

Sample D5510-A, slide 2, coordinates 92.6x14.7.

7. Cicatricosisporites pseudotripartitus (Bolkhovitina) Dettmann 1963 

Sample D5801, prep. 2, slide 4, coordinates 105.9x20.8.

8. Cicatricosisporites cf. C. pseudotripartitus (Bolkhovitina) Dettmann 1963 

Sample D5510-B, slide 1, coordinates 99.5x16.6.

9. Cicatricosisporites apiteretus Phillips and Felix 1971 

Sample D5510-C, slide 2, coordinates 89.7x10.5.

10. Cicatricosisporites cf. C. subrotundus Brenner 1963

Sample D5510-B, slide 1, coordinates 107.2x13.3.

11-12. Cicatricosisporites cf. C. crassistriatus Burger 1966

Sample D5801, prep. 2, slide 2, coordinates 110.3x1.0.

13. Cicatricosisporites cf. C. pseudotripartitus (Bolkhovitina) Dettmann 1963 

Sample D5510-C, slide 4, cordinates 108.5x13.0.

14. Appendicisporites bilateralis Singh 1971

Sample D5801, prep. 2, slide 4, coordinates 88.3x10.5.

15. Distaltriangulisporites perplexus (Singh) Singh 1971 

Sample D5803, slide 6, coordinates 75.9x10.0.

16. Distaltriangulisporites sp.

Sample D5510-B, slide 1, coordinates 73.0x9.0.

17. Appendicisporites jansonii Pocock 1962

Sample D5801, prep. 2, slide 2, coordinates 109.4x14.1.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 6

CICATRICOSISPORITES, APPENDICISPORITES, AND DISTALTRIANGULISPORITES
PLATE 7 

Burro Canyon Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers, (text fig. 2)]

FIGURE 1. Corollina torosa (Reissinger) Cornet and Traverse 1975 (two specimens) 

Sample D5803, slide 19, coordinates 79.0x20.1.

2. Equisetosporites sp.

Sample D5803, slide 12, coordinates 91.8x11.0.

3. Equisetosporites sp.

Sample D5803, slide 8, coordinates 80.4x12.9.

4. Cycadopites sp.

Sample D5803, slide 4, coordinates 90.8x20.2.

5. Cycadopites sp.

Sample D5803, slide 5, coordinates 105.3x13.6.

6. Cycadopites sp.

Sample D5803, slide 6, coordinates 108.8x12.4.

7. Exesipollenites tumulus Balme 1957

Sample D5803, slide 10, coordinates 76.6x6.1.

8. Araucariacites sp.

Sample D5510-C, slide 1, coordinates 72.2x1.1.

9. Cerebropollenites mesozoicus (Couper) Nilsson 1958 

Sample D5803, slide 3, coordinates 84.2x20.5.

10. Callialasporites segmentatus (Balme) Sukh-Dev 1961 

Sample D5803, slide 8, coordinates 93.2x16.0.

11. Callialasporites sp.

Sample D5510-C, slide 1, coordinates 76.9x18.0.

12. Cerebropollenites mesozoicus (Couper) Nilsson 1958 

Sample D5803, slide 22, coordinates 99.8x13.4.

13. Vitreisporites pallidus (Reissinger) Nilsson 1958 

Sample D5803, slide 21, coordinates 96.5x15.0.

14. Vitreisporites pallidus (Reissinger) Nilsson 1958 

Sample D5510-C, slide 4, coordinates 105.4x4.3.

15. Pristinuspollenites sulcatus (Pierce) B. Tschudy 1973

Sample D5803, slide 3, coordinates 110.8x20.7. 

16-17. Clavatipollenites hughesii (Couper) Kemp 1968 

Sample D5803, slide 12, coordinates 80.0x23.0.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE 7

17

COROLLINA, EQUISETOSPORITES, CYCADOPITES, EXESIPOLLENITES, ARAUCARIACITES, 

CEREBROPOLLENITES, CALLIALASPORITES, VITREISPORITES, PRISTINUSPOLLENITES,

AND CLAVATIPOLLENITES
PLATE 8 

Burro Canyon Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers (text fig. 2)]

FIGURE 1. Paleoconiferus asaccatus Bolkhovitina 1956

Sample D5808, slide 21, coordinates 108.1x17.8.

2. Alisporites thomasii (Couper) Pocock 1962

Sample D5510-C, slide 2, coordinates 99.6x1.6.

3. Pityosporites cf. P. divulgatus (Bolkhovitina) Pocock 1970 

Sample D5803, slide 21, coordinates 76.2x13.9.

4. Alisporites grandis (Cookson) Dettmann 1963 

Sample D5803, slide 5, coordinates 85.4x8.2.

5. Pityosporites nigraeformis (Bolkhovitina) Pocock 1970 

Sample D5803, slide 22, coordinates 89.8x21.6.

6. Pityosporites nigraeformis (Bolkhovitina) Pocock 1970 

Sample D5803, slide 22, coordinates 95.1x12.8.

7. Cedripites cf. C. car.ad^nsis Pocock 1962

Sample D5803, slide 21, coordinates 80.8x17.5.

8. Cedripites cretaceus Pocock 1962

Sample D5803, slide 21, coordinates 109.7x17.6
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1281 PLATE-8

PALEOCONIFERUS, ALISPORITES, PITYOSPORITES, AND CEDRIPITES
PLATE 9 

Burro Canyon Formation

[Magnification x 1000. Sample numbers are those of USGS Paleobotany locality numbers (text fig. 2)]

FIGURE 1. Podocarpidites ornatus Pocock 1962

Sample D5803, slide 16, coordinates 110.0x10.1.

2. Podocarpidites cf. P. ellipticus Cookson 1947

Sample D5803, slide 5, coordinates 98.7x19.1.

3. Podocarpidites cf. P. ornatus Pocock 1962

Sample D5803, slide 4, coordinates 89.3x11.4.

4. Podocarpidites cf. P. multesimus (Bolkhovitina) Pocock 1962 

Sample D5803, slide 21, coordinates 102.3x20.4.

5. Podocarpidites cf. P. ornatus Pocock 1962

Sample D5803, slide 21, coordinates 109.3x17.5.

6. Podocarpidites radiatus Brenner 1963

Sample D5803, slide 5, coordinates 111.5x9.7.
GEOLOGICAL SURVEY

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