DEPARTMENT OF THE INTERIOR 

FRANKLIN K. LANE, Secretary 

UNITED STATES GEOLOGICAL SURVEY 

GEORGE OTIS SMITH, Director 

Professional Paper 108-F 

A FOSSIL FLORA FROM THE FRONTIER FORMATION 

OF SOUTHWESTERN WYOMING 

BY 

F. H. KNOWLTON 

Published August 22, 1917 

Shorter contributions to general geology, 1917 

(Pages 73-107) 

WASHINGTON 

GOVERNMENT J?RINTING OFFICE 

1917 
CONTENTS. 

Page. 

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 

Stratigraphic relations................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 

Age of the Frontier formation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 

General features of the flora............................................................. . . . ..... . ......... 77 

Species now recognized. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 

Localities and collectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 

Biologic aspects of the flora. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 

Physical and climatic conditions indicated.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 

Evidence of insects in Frontier time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 

The flora ........................................... . ...... , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 

ILLUSTRATIONS. 

Page. 

PLATE XXVII. A, Plant-bearing shale in Frontier formation 1 mile east of Cumberland, Wyo.; B, White plantbearing shale in Frontier formation south of Little Muddy Creek, near Cumberland, Wyo.. 74 

XXVIII-XXXIX. Fossil flora from the Frontier formation·-··· ........................ . ........... 96-107 

II 
A FOSSIL FLORA FROM THE FRONTIER FORMATION OF SOUTHWESTERN 

WYOMING. 

By F. H. KNOWLTON. 

INTRODUCTION. 

This paper deals with a small but important 

fossil flora, now known to be of Colorado age, 

from the vicinity of Cumberland, Lincoln 

County, Wyo. It was for many years thought 

to be of Jurassic age, and only within the last 

decade has its stratigraphic position been established. Although small in number of species, this flora offers information bearing on the 

physical and climatic conditions that prevailed 

during early Upper Cretaceous time in this 

region, and, moreover, it furnishes a series of 

stratigraphic marks that may be used in the 

recognition of this horizon elsewhere. It h11s 

also a possibly important biologic bearing, for 

it shows the presenoe of certain plant types that 

are now found living in Polynesia. The presence of certain types of insects that lived in 

and on the plants is shown by their characteristic markings. Finally, this study has a historical and sentimental interest because it is 

based on material collected on the celebrated 

Fremont exploring expedition more than 70 

years ago and now rediscovered and redescribed. 

The fossil plants to be described in this paper 

were discovered in 1843 by Capt. John C. Fremont, while engaged on an exploring expedition that had for its object the finding of a 

''new and better road" over the mountains 

and plains to Oregon and northern California. 

On August 19, 1843, the expedition turned 

north from Fort Bridger, on the old Oregon 

Emigrant Road, and soon passed over Muddy 

Creek, near the present site of Carter, Uinta 

County, Wyo. The fossil plants were found 

somewhat farther north, on Little Muddy Creek, 

near the present line between Uinta and Lincoln counties. Fremont's description 1 of the 

discovery of the fossil plants is as follows: 

1 Fremont, J. C., Report of the exploring expedition to the Rocky 

Mountains in the year 1842, and to Oregon and north California in the 

years 1843-44: Twenty-eighth Cong., 2d sess., House Ex. Doc. 166, p.131, 

1845. 

August 19: A few miles from our encampment [of August 

18] the road entered a high ridge connecting the Utah with 

the Mud River chain; and in one of the hills near which 

we passed I remarked strata of a conglomerate formation. 

We crossed a ridge of this conglomerate and descended 

upon one of the heads of Hams Fork, called Muddy, where 

we made our midday halt. In the river hills at this place 

I discovered strata of fossiliferous rock having an oolite 

structure, which, in connection with the neighboring 

strata, authorize us to believe that here, on the west side 

of the Rocky Mountains, we find repeated the modern 

formations of Great Britain and Europe, which have hitherto been wanting to complete the system of North American geology. * * * 

In the afternoon we continued our road and, searching 

among the hills a few miles up the stream and on the same 

bank, I discovered among alternating beds of coal and 

clay a stratum of white indurated clay containing very 

clear and beautiful impressions of vegetable remains. 

This was the most interesting fossil locality I had met in 

the country, and I deeply regretted that time did not 

permit me to remain a day or two in the vicinity. * * * 

After remaining here only about an hour, I hurried off, 

loaded with as many specimens as I could conveniently 

carry. 

These plants were referred to James Hall,t 

then paleontologist to the State of New York, 

who named, described, and figured most of them 

in an appendix to Fremont's report. Hall also 

gave the following additional information concerning the locality, evidently derived from 

Fremont's notes: 

Longitude 111°, latitude 41! 0 , Muddy River: These 

specimens are of a yellowish-gray oolitic lil!lestone, containing turbo, cerithium, etc. The rock is a perfect oolite 

and, both in color and texture, can scarcely be distinguished from specimens of the Bath oolite. One of the 

specimens is quite crystalline, and the oolitic structure 

somewhat obscure. In this instance the few fossils observed seem hardly sufficient to draw a decisive conclusion 

r'egarding the age . of the formation; but, when taken in 

connection with the oolitic structure of the mass, its correspondence with the English oolites, and the modern 

aspect of the whole, there remains less doubt of the propriety of referring it to the oolitic period. A further collection from this interesting locality would doubtless 

1 Hall, James, Descriptions of organic remains collected by Capt. J. C. 

Fremont in the geographical survey of Oregon and north California: 

Idem, Appendix B, pp. 304-307, pis. 1, 2, 1845. 

73 
74 SHORTER CONTRIBUTIONS T'O GENERAL GEOLOGY, 1917. 

develop a series of fossils which would forever settle the 

question of the relative age of the formation. 

A few miles up this stream Capt. Fremont has collected a 

beautiful series of specimens of fossil ferns. The rock is 

an indurated clay, wholly destitute of carbonate of lime, 

and would be termed a ."fire clay." These are probably, 

geologically as well as geographically, higher than the 

oolite specimens, as the rocks at this place were observed 

to dip in the direction of N. 65° W. at an angle of 20°. 

This would show conclusively that the vegetable remains 

occupy a higher position than the oolite. Associated with · 

these vegetable remains were found several beds of coal 

differing in thickness. 

The stratum containing the fossil ferns is about 20 feet 

.thick, and above it are two beds of coal, each about 15 

inches. These are succeeded by a bed of sandstone_. 

Below the bed containing the ferns there are three distinct 

beds of coal, each separated by about 5 feet of clay. 

Before examining the oolitic specimens just mentioned I 

compared these fossil _ ferns with a large collection from 

the coal measures of Pennsylvania and Ohio, and it was 

quite evident that this formation could not be of the same 

age. There ate several specimens which I can only refer 

to the Glossopteris phillipsii (see description), an oolitic 

fossil; and this alone, with the general character of the 

other species and the absence of the large stems so common 

in the coal period, had led me to refer them to the oolitic 

period. I conceive, however, that we have scarcely sufficient evidence to justify this reference; and though among 

the fossil shells there are none decidedly typical of the 

oolite, yet neither are they so of any other formation; and 

the lithological character of the mass is not reliable evidence. Still, viewed in whatever light we please, these 

· fossil ferns must, I conceive, be regarded as mostly of new 

species and in this respect form a very important addition 

to the flora of the more modern geological periods. 

From the foregoing statement it appears 

that, although Hall tentatively referred these 

plants to the Oolite-that is, to the Upper 

. Jurassic-as perhaps the best disposition that 

could be made under the circumstances, he was 

by no means certain of their age. 

For more than 40 years after these plants 

were ·described and figured ·by Hall they remained in obscurity and practically lost. In 

1887 I found some of them, including five of 

the figured types, in the United States National Museum. They were without adequate 

labels and were thickly covered with dust and 

mingled with other material of miscellaneous 

and unknown origin. How they came into the 

possession of the National Museum, or where 

the rest of the collection is-if, indeed, it is in 

existence-,-is not now known. 

published 1 in 1888. Lesquereux changed a 

number of Hall's generic references-for example, Sphenopteris and Trichopteris to Thyrsopteris-but was evidently somewhat confused by the presence of apparent dicotyledonous leaves, which he forced into or compared with certairt genera of ferns and cycads. 

He referred them to the Jurassic, his statement 

being as follows: "What seems to me to be 

conclusive of the oolitic age of the plants is 

the number of fragments of small ferns referable to the genus Thyrsopteris, of which Heer 

has described a number of species from the 

Jurassic of Siberia." 

To return to the field relations of these 

plants, it appears that none of the Government expeditions that operated in this region 

after the early explorations of Fremont had 

happened to find the beds containing them, 

though they are now known to be conspicuous. 

A. C. Peale, of the Hayden Survey, studied the 

region a few miles to the north of the Cumberland area during the field season of 1877. He 

was therefore familiar in a general way with 

the stratigraphy of this part of Wyoming, and 

in 1898 he attempted to determine, in the office, 

from Fremont's account, the locality whence 

these fossils came but was not able to reach a 

satisfactory conclusion. The matter then 

rested for several years, until 1905. 

When A. C. Veatch, of the United States 

Geological Survey, · began his study of the coal 

and oil fields of this general region, Peale 

called his attention to this unique material 

and to the desirability of determining the true 

stratigraphic position of the original locality 

and of procuring additional collectio;ns. From. 

the knowledge Veatch soon acquired of the 

region, as well as from a careful consideration 

of the original notes of Fremont and Hall 

quoted above, the locality that furnished these 

plants was. determined to be on the south bank 

of Little Muddy Creek, about 1 mile -east of 

the present town of Cumberland. The account of this rediscovery was first given by 

Veatch 2 in a short article published in June, 

1906, and more at length in his formal report 3 

on the region in 1907. 

The great interest that attaches to these · • 1 Lesquereux, Leo, Recent determinations of fossil plants from Ken- · 

plants was recognized by me, and as Prof. Leo 'tucky, Louisiana, Oregon, etc., with descriptions of new species: u.s. 

Lesquereux was at that time engaged in study- Nat. Mus. Proc., vol. 11, PP· 37, 38, 1888. • • • • 2 Veatch, A. C., Age and type locality of the supposed Jurassic fossils 

mg and naming the miscellaneous fossil-plant collected north of Fort Bridger, Wyo., by Fremont in 1843: Am. Jour. 

material in the National Museum they were Sci., 4th ser., vol. 21, pp. 457- 460,1906. . • ' s Veatch, A. C., Geography and geology of a portion of southwestern 

sent to him for restudy, and his report was Wyoming: u. s. Geol. survey Prof. Paper 56, pp. 65-69, 1907. 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 108 PLATE XXVII 

.A. PLANT-BEARING SHALE IN FRONTIER FORMATION," 1 MILE EAST OF CUMBERLAND, WYO. 

Photograph by T. W. Stanton. 

B. WHITE PLANT-BEARING SHALE IN FRONTIER FORMATION SOUTH OF LITTLE MUDDY CREEK, 

NEAR CUMBERLAND, WYO. 

Probably very near the original Fremont locality. Photograph by T. W. Stanton. 

A FOSSIL FLORA FROM THE FRONTIER. FORMATION OF SOUTHWESTERN WYOMING. 7 5 

Veatch made a considerable collection of 

plants on the north side of Little Muddy 

Creek, in sec. 29, T. 19 N., R. 116 W., and in 

this collection the matrix, as well as a number 

of species, are absolutely identical with the 

original material collected by Fremont and 

preserved in the United States National 

Museum. There can be no doubt, therefore, 

that the beds from which Veatch's collection 

was obtained arenot only at the same horizon 

but at the same or approximately the same 

locality as that which furnished the Fremont 

collection of 1843. 

STRATIGRAPHIC RELATIONS. 

The plants described in this paper occur in 

what is now known as the Frontier formation. 

This formation was named by W. C. Knight 1 

in 1902 from the coal town of Frontier, near 

which the beds are well exposed. It was 

defined as being" composed of very thick beds 

of compact sandstone, with shales and coals 

having an approximate thickness of 2,000 feet." 

Knight stated that it was characterized by the 

presence of Ostrea soleniscus, a long, slender 

oyster which has a maximum length of 12 

inches, but subsequent study has shown that 

this species also occurs several thousand feet 

above the designated top of the Frontier formation. 

The Frontier formation was further described by Veatch 2 as follows: 

The pronounced sandstone layer or group of sandstone 

layers, occasionally conglomeratic and containing numerous specimens of the elongate oyster mentioned, produces 

a pronounced ridge, which was named Oyster Ridge by 

Hayden in 1872. This name was adopted by the King 

Survey and used on the maps of that organization. This 

group of sandstones has therefore been named the Oyster 

Ridge sandstone member of the Frontier formation. At 

several places minor sandstones or oyster-bearing ridges 

occur above the Oyster Ridge sandstone. * * * The 

Oyster Ridge sandstone is generally about 200 feet thick. 

Beneath the Oyster Ridge sandstone there are other sandstone layers, which produce pronounced ridges, but these, 

except near the northern extremity of the map, are definitely separated from and not readily confused with the 

main Oyster Ridge sandstone. The total thickness of 

this formation ranges from 2,200 to 2,600 feet. It is exposed along the east side of Mammoth Hollow throughout 

this area, and on the west side north of Hams Fork and 

between Little Muddy and Clear creeks. It outcrops 

west of the great Absaroka fault from the Evanston-Fort 

Bridger road south to Sulphur Creek. 

1 Knight, W. C., Coal fields of southern Uinta County, Wyo.: Geol. 

Soc. America Bull., vol. 13, pp. 542-544, 1902. 

2Veatch, A. C., Geography and geology of a portion of southwestern 

Wyoming: U.S. Geol. Survey Prof. Paper 56, p. 65, l907. 

The stratum that undoubtedly supplied the 

plants collected by Fremont and that was rediscovered by Veatch is about 1,200 feet below 

the top of the Oyster Ridge sandstone. It is 

also below the several minor sandstone ridges 

mentioned by Veatch. The fossiliferous layer 

is a hard, brittle white clay only a few inches 

thick, in the midst of white clay shales, which 

in the exposure near Cumberland are about 30 

feet thick. (See Pl. XXVII.) This almost 

snow-white band of shales is very conspicuous 

and may be traced for miles. The layer containing the plants was found to be fossiliferous 

at nearly every foot of its exposure, and in 

some places it is literally packed with remains, 

especially ferns, which, at least at the Cumberland locality, are the dominant types. This 

great abundance of plants in the bed makes it 

difficult to procure large or perfect specimens. 

AGE OF THE FRONTIER FORMATION. 

As already stated the plant-bearing bed discovered by Fremont and now placed in the 

Frontier formation was tentatively regarded 

by Hall as of Jurassic age, and this reference 

was accepted by Lesquereux, who restudied a 

portion of the original collection in 1888. Long 

before this date, however, the beds had come to 

be recognized as belonging to the Upper Cretaceous. Thus, in 1870, when Hayden 3 gave 

the name Oyster Ridge to the conspicuous 

sandstone ridge near Sulphur Creek, he said: 

"It [Oyster Ridge] is composed mostly of 

gray and yellow-gray sandstone, capped with a 

calcareous sandstone, filled with a small species 

of Ostrea, and belongs, I think, to the upper 

portion of the Cretaceous group-probably No. 

5." This is a virtual reference to the Fox 

Hills sandstone, though that term was not actu- . 

ally employed. 

Later, however, Oyster Ridge was directly 

referred to the Fox Hills by both the Hayden 

and the King surveys, and it is so assigned on 

the map of this region published by the King 

Survey. 

It is difficult to ascertain just when the 

Oyster Ridge sandstone and the associated 

sandstones, shales, and coals of the Frontier 

formation were first regarded as of Colorado 

age. At least as early as 1877 Meek 4 described 

invertebrates that he recognized as of this age, 

a Hayden, F. V., Geology of the Missouri Valley: U. S. Geol. Survey 

Terr., Prel. Rept. for 1870, p. 149, 1871. 

'Meek, F.B., U.S. Geol.Expl.40th Par. Rept., vol.4, pl.1, p.143, 1877. 
76 SHORTER CONTB.IBUTIONS TO GENERAL GEOLOGY, 1917. 

from the vicinity of Sulphur Creek, 3 miles 

west of Oyster Ridge, where they occur in a 

heavy sandstone which is the same as the 

Oyster Ridge sandstone but is in the western 

limb of the syncline. 

This condition was also recognized and 

briefly alluded to in 1892 by Stanton.1 In a 

longer paper published the following year Stanton 2 described a number of the invertebrates 

from the Sulphur Creek area which he r~garded 

as of undoubted Colorado age. 

Although Knight/ when he named the Frontier formation, did not definitely fix its age, he 

took occasion to say that he could "not find a 

Fox Hills fauna such as is common to the Fox 

F~ills of the eastern part of Wyoming" and, at 

least by inference, placed it lower than Fox 

Hills. Veatch 4 also obtained evidence which 

in his opinion strengthened the reference of the 

formation to the Colorado. He also mentions 

the discovery of numerous specimens of Inoceramus exogyroides, an invertebrate held to be 

of Benton age, 3,000 feet above the top of the 

formation, or approximately in the middle of the 

overlying Hilliard formation. Mr. Stanton informs me that he has since procured a distinctly Benton fauna from the same sandstone 

lentil from which Veatch collected, in the Hilliard formation about 3,000 feet above its base. 

Mr. Stanton has been kind enough to supply 

the following account of the invertebrates and 

their occurrence: 

The evidence from the in vertebrate faunas that the 

Frontier formation and the lower half of the Hilliard formation are of the age of the Colorado group was presented by 

Veatch o in 1907. Most of the Frontier invertebrates then 

known came from the upper part of the formation and from 

localities near the Union Pacific Railroad, 20 to 30 miles 

south of Cumberland. They include a number of very 

characteristic Colorado group species, which, in connection 

with the known stratigraphic relations and the fauna of the 

underlying beds, justified the reference of the whole 

Frontier formation, including the plant-bearing bed near 

Cumberland, to the Colorado group. 

Later collections and observations have confirmed and 

strengthened the evidence for the Colorado age of both the 

Frontier formation and the lower 3,000 feet or more of the 

overlying Hilliard formation, and they have a more direct 

bearing on the age of the plant bed because their relations 

to it are definitely determined. The white shales associ1 Stanton, T. W., The stratigraphic position of the Bear River formation: Am. Jour. Sci., 3d ser., vol. 43, p. 105, 1892. 

2 Stanton, T. W., The Colorado formation and its invertebrate fauna: 

U. S. Geol. Survey Bull. 106, 1893. 

3 Knight, W. C., Coal fields of Southern Uinta County, Wyo.: Geol 

Soc. America Bull., vol. 13, p. 543, 1902. · 

4 Veatch, A. C., Geography and geology of a portion of southwestern 

Wyoming: U. S. Geol. Survey Prof. Paper 56, p. 69, 1907. 

6 Veatch, A. c., .op. cit., pp. 66--68, 71, 72. 

ated with the plant bed may be traced along the strike for 

many miles north and south of Cumberland. Tothenorth 

they have been recognized near Glencoe, Oakley, and as 

far as Kemmerer, holding the same position far beneath the 

Kemmerer coal, which is mined at all these places. Two 

collections received from the late Robert Forrester have 

been identified as follows: 

120 feet above· Kemmerer coal, near Oakley, Wyo.: 

Ostrea sp. 

Jnoceramus related to I. deformis Meek. 

Inoceramus sp. 

V eniella goniphora Meek. 

Baculites gracilis Shumard? 

Scaphites ventricosus Meek and Hayden? 

Roof of Kemmerer coal, Glencoe mine, Glencoe, Wyo.: 

Ostrea sp. 

A vicula gastrodes Meek. 

Inoceramus labiatus Schlotheim? 

Nemodon? sp. 

Cardium pauperculum Meek. 

Mactra? sp. 

Corbula sp. 

Melania? sp. 

Scaphites ventricosus Meek and Hayden. 

All the identified forms in these two lots are character:-

istic of the fauna of the Colorado group, and most of them 

in other regions would indicate the upper part of the group, 

but in this western Wyoming area the Upper Cretaceous 

sediments are abnormally thick and many species seem to 

have an unusual vertical range, indicating rapid sedimen-· 

tation. Thus the sandstone lentils near the middle of the 

Hilliard formation about 3 miles northwest of Kemmerer, 

though fully 3,000 feet above the horizon of the two collections last mentioned, still yield a characteristic Colorado 

fauna. Veatch recorded the presence of Inoceramus exogyroides in these lentils and correctly assigned the beds to the 

Colorado group. In 1913 I collected from these sandstones, 

which, according to Veatch, lie from 3,000 to 3,800 feet 

above the base of the Hilliard formation, the following 

species: 

Ostrea soleniscus Meek. 

A vicula gastrodes Meek? 

Inoceramus umbonatus Meek and Hayden. 

Inoceramus exogyroides Meek and Hayden. 

Inoceramus cf. I. undabundus Meek and Hayden. 

Inoceramus fragilis Hall and Meek? 

Cardium pauperculum Meek. 

Cyprimeria? sp. 

Donax oblonga Stanton. 

Tellina? sp. 

Mactra emmonsi Meek. 

Mactra sp. 

Martesia? sp. 

Pugnellus fusiformis (Meek). 

Placenticeras sp. cf. P. pseudoplacenta Hyatt. 

None of the species in this list is known to range above 

the Colorado group. The first two species of Inoceramus are 

especially abundant and are characteristic of a horizon 

near the top of the Colorado not far below the Eagle sandstone on Missouri River below Fort Benton, Mont. The 

Donax and the Pugnellus are equally characteristic of a 

sandstone in the Colorado group above the principal coal 

bed at Coalville, Utah. 
A FOSSIL FLORA FROM THE FRONTIER FORMATION OF SOUTHWESTERN WYOMING. 77 

The evidence of the plants as to the age of the 

beds containing them was first believed to be in 

substantial accord with that of the invertebrates. In my report 1 on the plants collected 

by Veatch I made the following statement regarding their position: "The age, so far as I am 

able to fix it, is the lower part of the Upper Cretaceous, about the position of the Turonian, 

possibly a little lower." 

The Colorado age of the Frontier formation, 

as based on stratigraphie position and the evidence of the invertebrates, is here accepted. It 

is but fair to state, however, that the critical 

study of the plants does not lend conclusive 

support to their reference to the Colorado. Inasmuch as practically all the forms are new to 

science, the interpretation of their bearing on 

the question of age must be made through 

their affinities, and these, so far as they can be 

made out, appear to favor a position stratigraphically higher than the Colorado. This 

evidence may be briefly reviewed as follows: 

The spleenwort (Asplenium occidentale) belongs to the same group as and is pretty closely 

related to an unpublished species from the 

Farmington sandstone member of the Kirt-

. land shale (Montana group) of San Juan 

County, N. Mex. The shield fern (Dryopteris 

coloradensis) is strongly suggestive of an unpublished species from the Vermejo formation 

of the Raton Mesa region of Colorado and New 

Mexico. The Anemia is very closely related to 

and perhaps identical with a species common in 

the Eocene of Europe but also reported from the 

Montana at Point of Rocks, Wyo. Among the 

dicotyledons, Oinnamomum hesperium is hardly 

distinguishable, except in size, from Oinnamomum wardii, from the upper part of the Adaville formation at Hodges Pass, a few miles 

north of the Cumberland localities. Dewalquea 

pulchella and Dryandroides lanceolata are so 

close to Dewalquea insignis and Dryandroides 

quercinea, respectively, from the Upper Senonian of Westphalia, that it is perhaps doubtful 

if they should be maintained as distinct. 

Quercus stantoni is very similar to Quercus 

formosa, also from the Senonian of Westphalia. 

Ficus fremonti agrees in shape with Ficus 

proteoides Lesquereux, and in shape, size, and 

nervation with Ficus lanceolata acuminata 

Ettingshausen, as figured by Lesquereux, from 

I Knowlton, F. H.,in Veatch, A. C., Age and type localities of supposed 

Jurassic fossils collected north of Fort Bridger, Wyo., by Fremont in 1843: 

Am. Jour. Sci., 4th ser., vol. 21, p. 459, 1906. 

the Dakota sandstone. This is the only species 

that appears to show any special like,ness to 

forms from beds whose position is lower than 

that assigned to the plant beds at Cumberland. 

The foregoing is not the only evidence for 

assigning the Frontier formation to a position 

higher than the Colorado, though ~he additional 

evidence is not so strong as it was supposed at 

one time to be. In 1907 A. R. Schultz, of the 

United States Geo1ogical Survey, began an 

investigation of the coal resources of the socalled Rock Springs dome, about 75 miles east 

of the Cumberland area. Incidentally to this 

study Schultz procured a number of very interesting collections of fossil plants, mainly from 

thin, indurated clay partings in coal. The age 

of these plants has been fixed as near the middle 

of the Mesaverde formation (Montana group), 

in what has been called the Rock Springs coal 

group. The most abundant plants are ferns of 

the genera Gleichenia and Anemia, and the 

dicotyledons are comparatively few. This 

flora has a facies strikingly similar to that of 

the flora from the Frontier formation, and as 

several species appeared to be in common, I 

held that the plant-bearing beds at Cumberland 

and Rock Springs were identical in age. A 

critical study of the Frontier flora, however, 

discloses the fact that there are apparently no 

dicotyledons and few if any ferns common to 

the two areas. 

GENERAL FEATURES OF THE FLORA. 

SPECIES NOW RECOGNIZED. 

Before proceeding to a discussion of the 

various aspects of this flora, it will be of interest 

to present the following complete list of the 

forms now recognized: 

Tapeinidium? undulatum (Hall) n. comb~ 

Microtaenia variabilis n. gen. and n. sp. 

Microtaenia paucifolia (Hall) n. comb. 

Dennstaedtia? fremonti (Hall) n. comb. 

Dryopteris coloradensis n. sp. 

Asplenium occidentale n. sp. 

Anemia fremonti n. sp. 

Equisetum sp. 

Smilax? coloradensis n. sp. 

Myrica nervosa n. sp. 

Salix cumberlandensis n. sp. 

Salix frontierensis n. sp. 

Quercus stantoni n. sp. 

Ficus fremonti n. sp. 

Ficus? sp. 

Ficus? sp. 

Cinnamomum hesperlum n. sp. 

Cinnamomum? sp. 
78 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1917. 

Dryandroides lanceolata n. sp. 

Aralia veatchi.i n. sp. 

Staphylea? fremonti n. sp. 

Dewalquea pulchella n. sp. 

Phyllites fic.ifolia n. sp. 

Phyllites dentata n. sp. · 

Phyllites. 

LOCALITIES AND COLLECTORS. 

I. Probably on the south bank of Little 

Muddy Creek about l mile east of the present 

town of Cumberland, Wyo. Collected by J. C. 

Fremont August I9, I843. Below is a list of 

the species described by Hall with their present 

disposition: 

Sphenopteris fremonti Hall=Dennstaedtia? fremonti. 

Sphenopteris triloba Hall=Microtaenia paucifolia. 

Sphenopteris? paucifolia Hall=Microtaenia paucifolia. 

Sphenopteris? trifoliata Hall. 

Glossopteris phillipsi?=Ficus fremonti. 

Pecopteris undulata Hall=.Tapeinidium? undulatum. 

Pecopteris undulata var.=Tapeinidium? undulatum. 

Pecopteris? odontopteroides Hall=Tapeinidium? undulatum. 

Trichopteris filamentosa Hall=rootlets of ferns. 

Trichopteris gracilis Hall=rootlets of ferns. 

Leaf of dicotyledonous plant?=Phyllites fremonti Unger. 1 

2. North branch of Little Muddy Creek I mile 

east of Cumberland, Wyo. Collected by A. C. 

Veatch August 3, I906. 

Tapeinidium? undulatum. 

Dryopteris coloradens.is. 

Equisetum sp. 

Aralia veatchii. 

Dewalquea pulchella. 

3. Approximately same locality as No. 2. 

Collected byT. W. Stanton and F. H. Knowlton 

August 5, I908. 

Tapeinidiutn? undulatuill. 

Microtaenia variabilis. 

Microtaenia paucifolia. 

Dennstaedtia? fremonti. 

Asplenium occidentale. 

Anemia fremonti. 

Ficus fremonti. 

Staphylea? fremonti. 

Phyllites ficifolia. 

Insect mine in leaflet of Staphylea. 

4. Mine No. I, Cumberland, Wyo. Collected 

by F. H. Knowlton August 6, I908. 

Smilax? coloradensis. 

l This is apparently not from the Frontier formation but probably 

from the Green River formation 40 or 50 miles east of the Cumberland 

locality. (Seep. 94.) 

5. About half a mile east of Cumberland, 

Wyo. Collected by T. W. Stanton and F. H. 

Knowlton August 5, I908. 

Ficus? sp. 

Ficus? sp. 

Cinnamomum? sp. 

6. About I mile east of Cumberland, Wyo. 

Same horizon as principal Cumberland locality 

but at a slightly different point. Collected by 

A. C. Peale August I8, I909. 

Ficus fremonti. 

Aralia veatchi.i. 

7. About It miles south of Cumberland, 

Wyo., in theSE. i sec. 6, T. I8 N., R. II6 W. 

Same horizon as locality I mile east of Cumberland, and probably near the original Fremont 

locality. Collected by T. W. Stanton September I, I9I3. · 

Tapeinidium? undulatum. 

Myrica nervosa. 

Salix cum berlandensis; 

Salix. 

Quercus stantoni. 

Ficus fremonti. 

Cinnamomum hesperium. 

· Dryandroides lanceolatum. 

Phyllites dentata. 

Phyllites. 

8. About I mile east of Oakley and 3 miles 

southeast of Kemmerer, Wyo., in the SW. i 

sec. 3, T. 2I N., R. II5 W. Collected by T. W. 

Stanton September 2, I9I3. 

Ficus fremonti .. 

Quercus stantoni. 

Fragments of dicotyledons, not determinable. 

BIOLOGIC ASPECTS OF THE FLORA. 

The known flor~ from the Frontier formation near Cumberland embraces 25 forms, of 

which 7 are ferns, I an Equisetum; I a monocotyledon (Smilax), and the remaining I6 

dicotyledons. As regards the relative abundance of the different types,' it is probable that 

the ferns outnumber the other forms by perhaps 

two to one. Several of the dicotyledons are 

based on single specimens, but there is hardly 

a piece of matrix without fragments of ferns. · 

The first four species of ferns enumerated 

in the list on page 77 possess great biologic 

interest. They form a natural group that, 

from their peculiar and well-marked type of 
A FOSSIL FLORA FROM THE FRONTIER FORMATION OF SOUTHWESTERN WYOMING. 79 

fructification, marks them as being undoubtedly davallioid-that is, clearly allied to the 

group of mainly tropical ferns of whi~h the 

genus Davallia is the central form. They are 

entirely unlike anything now living in the 

New World and appear to find their closest 

relatives among species now living in Polynesia. Thus the Tapeinidium, although far 

from being conspecific with any living form of 

the genus, appears to be most closely related to 

Tapeinidium pinnatum ( Ca vanilles) C. Christensen, a species widely dispersed in Malaysia and 

Polynesia. The two species called Microtaenia 

are so wholly unlike any living or fossil form 

known that it has been necessary to create a 

new genus for their reception. They are very 

abundant in individuals, showing that they 

formed a well-established element in the 

Frontier flora. The species referred to Dennstaedtia is not so well established as either of 

the first three forn1s in the list and is based on a 

few fragments that may possibly represent an 

extreme modification of Microtaenia paucifolia. The genus Dennstaedtia is a large 

group comprising more than 60 species. They 

are of wide, mainly tropical distribution, only 

one species (D. punctilobula), the so-called hayscented fern, inhabiting North America; this 

species is quite unlike the fossil form under 

discussion. 

The single species of shield fern (Dryopteris) is of an ordinary type, but the spleenwort (Asplenium occidentale) belongs in the 

group of living species of which A. hemitonites 

Linne is the type. Anemia is also a large 

genus of almost exclusively tropical American 

forms, only two inhabiting the United Statesone in peninsular Florida, the other in southern Texas and extending into adjacent parts 

of Mexico. 

The horse-tail (Equisetum sp.) is so poorly 

represented that it has little value beyond 

indicating the presence of this type of vegetation. 

The smilax, the only form referred to the 

monocotyledons, is based on a single specimen 

and is of doubtful biologic value. 

The dicotyledons are represented by a number of well-known types. They include a 

coriaceous-leaved waxberry (Myrica), two 

willows (Salix), and a small-leaved oak (Quercus), all of which are very modern in appearance. The named species of fig (Ficus fre816380-17-2 

monti) is so placed on account of its general 

resemblance to and affinity with certain described fossil species, and not on account of its 

relationship with living members of the genus. 

Ficus is a vast, mainly tropical group comprising over 600 species. The named form referred to Cinnamomum, the well-known cinnamon tree, is of the type of an unidentified 

living species from China. The genus is not 

now a native of the New World, its center of 

distribution being tropical and subtropical 

portions of southeastern Asia. The species of 

Dryandroides, if correctly placed, is of importance as showing the presence of the 

Proteaceae in this country during early Upper 

Cretaceous time, but it is so fragmentary 

that I can not be certain of its position. 

PHYSICAL AND CLIMATIC CONDITIONS 

INDICATED. 

From the facts now available it appears unquestionable that at least the major portion 

of the Frontier formation was laid down in 

fresh water. This is proved by the numerous, 

thick, and widespread beds of coal it contains. 

The coal swamps of that epoch, which must 

have been of wide extent and long duration, 

might well have been and doubtless were but 

little above sea level, for sandstones containing oysters occur both below and above certain of the coal beds, showing slight oscillation that permitted the access of at least 

brackish water. No strictly marine organisms 

are known. About 1,000 feet below the top of 

the formation there are several thick beds of 

unios which indicate that the water at that 

time was fresh. There is nothing in the flora 

to indicate that any of its members required 

or indeed could tolerate a saline habitat; on the 

contrary, they could have found a congenial 

home only in or near fresh-water swamps and 

forests. 

The climate during Frontier time appears to 

have been tropical or subtropical, as is shown 

in a number of ways. Thus, one of the most 

abundant of the ferns (Tapeinidium) was indeterminate in growth, a condition that could 

survive to the extent here indicated only in 

the absence of frosts. The most abundant 

elements in this flora are the ferns, and of these 

the davallioid forms (Tapeinidium, Mic1·otaenia, and Dennstaedtia), to which may be 

added the Anemia, all call for a tropical or 
80 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY,. 1917. 

subtropical habitat. The spleenwort (Aspleniu~), if its affinity has been correctly interpreted, likewise calls for at least a subtropical 

setting, as do~s the single shield fern (Dryopteris). . The smilax is too incompletely known 

to permit a generalization concerning its climatic environment, though it must have been 

as warm as warm temperate and might well 

enough have been still warmer. The waxberry (Myrica), the oak (Quercus), and the 

willows (Salix), on the other hand, might not 

be out of place in a temperate region, but the 

figs (Ficus) and the cinnamon trees ( Cinnamomum) certainly required a tropical or subtropicalloca tion. 

EVIDENCE OF INSECTS IN FRONTIER TIME. 

An interesting though very meager fragment of information concerning the insect ]jfe 

of Frontier time has resulted from this study. 

Evidence of the presence of insects was noted 

on two leaves. One of these leaves (see Pl. 

XXXV, fig. 5), now named Ficusjremonti, was 

found by Frenwnt and is fortunately one of 

those in the collection of the United States 

National Museum. This specimen was figured 

by Hall, 1 who noted the presence of a cluster 

of circular bodies on one side of the leaf. He 

was uncertain as to the nature of these bodies, 

and as he had referred the leaf to Glossopteris 

phillipsi, a fern, he suggested that they might 

possibly represent the fruiting stage, though 

he adds: "This structure is so partial that iy 

can only with doubt be referred to the fructification of the plant; and it is not improbable 

that the same n1ay be some parasitic body or 

the eggs of an insect which have been deposited 

upon the leaf." This specimen was shown to 

Dr. August Busck, of the Bureau of Entomology, who at once recognized these circular 

bodies as an undoubted insect egg mass, probably of a microlepidopterous insect. 

The other specimen, shown in Plate XXXIII, 

figure 5, is a leaflet of Staphylea? fremonti 

in which ·a symmetrically looping mine has 

been made in the leaf substance by an insect 

larva. This Dr. Busck pronounced also to be 

the work of a microlepidopter, possibly belonging to the genus Phylloenistis. The mine 

appears to increase slig~tly in size from the 

apex of the leaflet toward the base, the exit 

being the basal margin next to the n1idrib. 

The work of this Frontier insect is absolutely 

similar in character to that of forms now living, 

a fact which would seem to indicate that the 

habits of life have persisted with no observable 

change from middle Cretaceous time to the 

present. THE FLORA. 

Family POLYPODIACEAE. 2 

Tapeinidium? undulaturn (Hall) Knowlton, n. comb. 

Plate XXVIII, figures 1-4. 

Pecopteris undulata Hall, in Fremont, Report of the 

exploring expedition to the Rocky Mountains in 

1842, etc., Appendix B, p. 306, pl. 1, figs. la, 1b, 

1845. -

Pecopteris undulata Hall, var., idem, p. 306, pl. 1, figs. 

2, 2a, 2b. 

Pecopteris? odontopteroides Hall, i~em, p. 306, pl. 1, figs. 

3, 4. 

Outline and habit of whole frond not known 

but·presumed to be simply pinnate, lanceolate 

in outline, gradually narrowed to the apex 

(base not seen); rachis strong, ridged, in places 

slightly winged; pinnae numerous, at right 

angles to the rachis, sessile, linear in general 

outline, sharp-pointed at apex, cut in v;arying 

degree into numerous rounded, slightly oblique 

or fan-shaped lobes which are entire or slightly 

erose-dentate; the lobes decrease in size apjcally, becoming merely undulations, the tip 

being almost or quite entire; upper , pinnae 

reduced in size, with undulate or almost entire 

margins; nervation of pinnae eonsisting of ll, 

very strong, grooved midvein, the lobes provided with a thin, delicate midvein and usually 

about three pairs of once-forked veins. 

This species is exceedingly abundant, probably the most abundant plant found in these beds, 

as there is hardly a pieee of matrix that does no't 

contain a fragment. In spite of its abundance, 

however, it is very rarely that specimens of 

considerable size and completeness are procured. It was apparently very brittle and 

easily broken up before it was entombed. The 

most complete example thus far found is that 

shown in figure 3, which has a preserved length 

of 12 centimeters but was undoubtedly considerably longer than this when perfect. The 

2 In the study of the ferns, especially the first four species, I have had 

1 Hall, James, in Fremont, J. c., Report of the exploring expedition the benefit of the assistance and critical judgment of Mr. W • R. Maxon, 

to the Roc:Ky Mountains in the year 1842, and to Oregon and North of the United States National Museum. My thanks are due to Mr. 

California in the years 1843-44~ Twenty-eighth Cong., 2d sess., House Maxon for detecting and pointing out affinities and interrelationships 

Executive Doc. 166, pl. 2, figs. 5b, 5c, 1845. that would otherwise have been overlooked. 
A FOSSIL FLORA FROM THE FRONTIER FORMATION OF SOUT'HWEST'ER.N WYOMING. 81 

width, of course, varies according to the position in the frond, the ma.ximum width being 

6 or 8 centimeters. In the upper pa.rt of the 

frond the pinnae a.re continuous, but in the 

middle a.nd lower pa.rts some of them a.re 

sepa.ra.ted by a. distance of once or twice their 

width. 

An interesting feature connected with the 

manner of growth in this fern is tha.t it a.ppea.rs 

to be indeterminate in growth-that is, the 

a.pica.l bud continued active a.nd the frond continued to grow indefinitely. This is a. condition not unknown a.mong living ferns, though 

its recorded occurrences a.re not numerous. It 

is presumed to occur, a.t lea.st to a. noticeable 

degree, only in ferns ~f a. tropical habitat, 

where absence of frost would permit the· delicate growing tip to survive. 

It has been difficult to place this fern biologically, a.nd for information a.nd advice concerning its position I am greatly indebted to 

Mr. W. R. Maxon, of the United States N ationa! Museum. It has, at lea.st superficially, 

some features of resemblance to Gleichenia, 

such as the size and shape of the pinnae and 

the thin right-angled insertion on the rachis, 

but on closer inspection it is seen that the lobes 

or segments of the pinnae are really oblique or 

somewhat unequal-sided. The · forked veins 

also exclude the present form from Gleichenia. 

In . habit this form somewhat approaches 

certain species of Dryopteris, but, all things considered, its characteristic features appear to be 

davallioid and to approach most closely those 

of Tapeinidium, a small genus of fern species 

of pinnate form, mainly natives of the Polynesian Islands. 

Although Hall described this fern under two 

specific names and one varietal name, the distinctions are based mainly on size a.nd it is not 

believed tha.t they can be ma.inta.ined. Thus 

the type of his Pecopteris undulata (his Pl. I, 

fig. 1a) is evidently a. segment from the middle 

part of a. large frond, where the pinnae are 

s.eparated by a considerable interval, as shown 

in Pla.te XXVIII, figures 1 and 4. Hall's Pecopteris? odontopteroides (his Pl. I, figs. 3, 4) is based 

on small pinnae with ·undulate or slightly cut 

margins that can be duplicated in the upper portion of the frond shown in Plate XXVIII, figure 

3. The form described by Hall as a. variety of 

Pecopteris undulata (his Pl. I, fig. 2) is also a segment from the middle or lower pa.rt of a. very 

large frond, and the pinnae, although broader 

than a.ny others noted, are not cut so deeply by 

the lobes a.s many smaller ones. If it has been 

correctly drawn, however, it appears to be 

slightly different from the normal forms, but 

even so it is hardly entitled to separate recognition. The other specimens referred to this 

variety (Hall's Pl. I, figs. 2a., 2b) are clearly 

segments with nearly entire pinnae from nea.r 

the apex of a frond of the normal type. 

The nervation of the pinnules shown by Hall 

in his Plate I, figures 1 b and 2a., is incorrect, 

as the lateral nerves are shown as simple a.nd 

unforked, although he describes the veins in 

the text a.s forking. As may be seen from the 

enlargement shown in figure 2a, the nervation 

consists of a thin, delicate midvein a.nd two or 

three pa.irs of once-forking veins. 

The only specimen of the original Fremont 

collection known to be extant is one of the 

types of Pecopteris? odontopteroides, figured by 

Hall in his Plate I, figure 4. It is No. 30848 

of the United States N ationa.l Museum collections. 

Occurrence: Frontier formation, about 1 n1ile 

ea.st of Cumberland, Wyo. Collected originally 

by J. C. Fremont August 19, 1843. Subsequently collected by A. C. Veatch in 1906 a.nd 

by F. H. Knowlton and T. W. Stanton in ~908. 

Genus MICROTAENJA 1 Knowlton, n. gen. 

Small davallioid,· pinnate herbaceous ferns, 

with close, linear, acute pinnules; lower pinnules barren, entire or slightly crenulate-margined; middle pinnules incompletely fertile; 

upper ones more completely or wholly fertile, 

reduced, becoming undulate, then cut nearly 

to the mid vein into sharp-pointed lobes; sori 

large, terminal, somewhat elongate, occupying 

the whole of the tips of the lobes. 

Type, Microtaenia 'variabilis. 

Microtaenia variabilis Knowlton, n. sp. 

Plate XXIX, figures l-4a. 

Size a.nd shape of whole frond unknown but 

apparently at least bipinna.te, the divis~ons 

(frond?) lanceolate in outline, narrowed at ba.se, 

acutish a.t apex; rachis slender, distinctly sulcate; segments or pinnules numerous, approximately a.t right angles to the rachis, close to 

1 From JL•Kpos, small, and T<nv.a, Latin taenia, a ribbon, in allusion to 

the narrow, ribbon-like pinnules. 
82 SHORTER CONT'RTBUTIONS TO GENERAL GEOLOGY, 1917. 

distant, linear and grasslike in shape, slenderly 

acuminate at apex, truncate or very slightly 

heart-shaped or halberd-shaped at base, closely 

sessile; lower barren pinnae entire or very 

slightly . undulate; middle · pinnules incompletely fertile, the fertile portion reduced, cut 

nearly to the midvein into sharp-pointed lobes; 

sori terminal or elongate, occupying nearly the 

whole outer part of the lobe; nervation of pinnules obscure, consisting of a very strong, 

sulcate midvein and apparently delicate, onceforked lateral veins which are at a low, almost 

right angle with the midvein. 

This very strongly marked type is represented by a large number of specimens, some of 

which, it will be seen, are exceptionally well 

preserved. In spite of the profusion of specimens, however, none are so complete as to give 

incontestable evidence as to the size and shape 

of the whole frond, though it appears to have 

been at least bipinnate. The two largest segments preserved, shown in figures 1 and 2, are 

from th,e lowest portion- of the frond, but 

neither quite reaches the base. They are narrowly lanceolate in outline, narrowing below 

to their point of attach:nient. Another specimen not figured shows that the apex also narrows and becomes acutish. The largest of the 

segments has a preserved length of 10 centimeters and a maximum width of about 4 

centimeters. Its full length was probably not 

less than 15 or 18 centimeters. 

The pinnules are all approximately at right 

angles to the rachis. In the specimen shown 

in figure 2, which must be very near the base of 

the frond, the pinnules are close together, but 

in the upper portion they become more distant, 

and in the specimen shown in figure 1 they are 

separated by more than the width of the pinnules. In other specimens, such as those shown 

on the left of figure 2 and in figure 4, the pinnules are separated by two or three times their 

width. The pinnules clearly are more distant 

in the middle and upper portions, where the 

frond is becoming fertile. 

Most of the barren pinnules are entire or 

nearly so, as shown, for instance, in figure I, 

but· a tendency to variation is constantly manifest. Thus, in figure 2, which to all intents and 

purposes is about the same as figure I, the 

pinnules show a decided tendency to be undulate margined and some of them to become distinctly lobed near the tips. In the fragmentary 

specimen on the left of the stone shown in 

figure 2 the exceedingly long, narrow pinnule 

is lobed up to the point where it becomes 

fertile, as are the other, broken pinnules, 

though the undulate lobed to strongly cut 

fertile portions are well shown in figure 3. 

None of these pinnules is completely fertile, 

each having a short barren, undulate-lobed 

portion near the base. In the specimen shown 

in figure 4a the whole of the pinnule has become fertile. 

The sori are perhaps best shown in figure 3. 

They are seen to be terminal and somewhat 

elongate and to occupy the whole of the tips of 

the lobes. 

The relationships of this fern are not easy to 

determine. That it is extremely variable in a 

number of particulars has been brought out in 

the above discussion. In certain specimens in 

which the barren pinnules are more or less 

undulate lobed this species appears to approach 

what is here called Tapeinidium? undulatum. 

Some specimens of that species have pinnules 

only slightly lobed and are almost impossible 

to distinguish from the present form. The 

character of the mid vein is exactly t~e same in 

both forms-that is, it is strong and deeply 

sulcate, thus producing the appearance of two 

lines when seen from the upper side of the 

pinnule. 

So far as can be learned by study of the 

figures given by Hall and such of the original 

material as is now accessible, Fremont did not 

collect specimens of Microtaenia variabilis unless the fertile upper portion of Hall's Sphenopteris triloba (his Pl. II, fig. 2) is an isolated 

fragment of a pinnule. 

Occurrence: Frontier formation, 1! miles 

east of Cumberland, Wyo. Collected by F. H. 

Knowlton and T. W. Stanton August 5, 1908. 

Microtaenia paucifolia (Hall) Knowlton, n. comb. 

Plate XXX, figures 1, 2. 

Sphenopteris? paucijolia Hall, in Fremont, op. cit., Ar- pendix B, p. 304, pl. 2, figs. 1, la, b, c, d . . 

Sphenopteris? trijoliata Hall, idem, pl. 2, fig. 2. 

Similar in general effect to the type species 

but evidently more finely divided, probably 

tripinnatified, the rachis much more slender; 

complete barren pinnules not seen; basal barren 

portion of fertile pinnules strongly undUlate 
A FOSSIL FLORA FROM: THE FRONTIER FORMATION OF SOUTHWESTERN WYOMING. 83 

lobed; fertile pinnules very short, with only 

two or three lobes on each side; sori terminal, 

occupying the whole of the tip. 

There is more or less uncertainty regarding 

the status of this form. It is represented by 

only four or five very fragmentary specimens, 

all of which show the fertile pinnules but give 

very little evidence regarding the barren portions. In the first place, it appears to be more 

finely divided than M. variabilis, as shown in 

one of Hall's figures (his .Pl. II, fig. 1) of S phenopteris? paucijolia, though none of the recent 

specimens is sufficiently complete to show this 

feature. The specimen shown in Hall's figure 

is certainly tripinnatified, with the pinnules 

short and very much reduced. 

The only evidence regarding the character of 

the barren pinnules is shown in figure 2, where 

the basal portions of three or four of the lower 

pinnules are seen to be undulate lobed before 

they pass into the deeply lobed, fertile portion. 

The specimen named Sphenopteris triloba by 

Hall is probably only a smaller and more 

reduced state of S. paucijolia in which the 

fertile lobes are reduced to three. It may be 

that the pinnules are broken at the tips, but 

as the specimen is not now known to be extant, 

it is impossible to settle this point. 

In the upper portion of Hall's figure 2 he 

shows the axis apparently passing into a 

fertile portion (enlarged in his fig. 2d), but this 

portion is only accidentally in that position and 

has no organic connection with the rest of 

the specimen. It appears to be an isolated 

fragment of a fertile pinnule of Jl!. variabilis. 

Occurrence: Frontier formation, 1! miles 

east of Cumberland, Wyo. Collected by F. I-I. 

Knowlton and T. W. Stanton August 5, 1908. 

Dennstaedtia? frernonti (Hall) Knowlton, u. comb. 

Plate XXX, figure _5; Plate XXXI, figure 1. 

Sphenopterisjremonti Hall, in Fremont, op. cit., Appendix 

B, p. 304, pl. 2, figs. 3, 3a. 

Size and shape of whole frond unknown but 

probably at least tripinnate or tripinnatified; 

main rachis exceedingly strong, ridged; pinnae 

approximately at right angles to the rachis, 

linear or lanceolate, with the secondary rachis 

sulcate; pinnules rather remote, subovate, 

somewhat decurrent at base, about three or 

four lobed; sori large, terminal on the tips of 

the lobes. 

This form is represented by so few and so 

fragmentary specimens that it must stand as 

insufficiently characterized. The most important features that can be made out are the 

exceedingly thick main rachis; small, fewlobed pinnules; and rather large, terminal sori. 

As regards the probable affinity of this form 

the best that can be said is that it is undoubtedly a davallioid fern, which as a matter of 

convenience is tentatively referred to the genus 

Dennstaedtia. 

Occurrence: Frontier formation, about 1 mile 

east of Cumberland, Wyo. Collected by J. C. 

Fremont August 19, 1843, and by F. H. 

Knowlton and T. W. Stanton August 5, 1908. 

Dryopteris coloradensis Knowlton, n. sp. 

Plate XXX, figures 3, 4. 

Outline of whole frond not known but evidently of large size and at least bipinnatified; 

rachis strong, round; pinnules at an angle of 

about 30°, alternate, rather remote, linearlanceolate, acuminate at apex, broadest at base, 

sessile, cut more than half the distance to the 

secondary rachis into numerous close, slightly 

scythe-shaped, obtusely pointed, or somewhat 

acute lobes; small upper lobes entire, larger 

lobes uneven or in places sharply serrate; 

secondary rachis slender; nervation of the lobes 

consisting of a thin, slightly flexuose midvein 

and five or six pairs of delicate, once-forked 

veins, the fork occurring just above the midvein; fructification not seen. 

This form is represented by several pieces, 

two of the most complete of which are figured. 

From the presence of large pieces of stems 

intermingled with the fronds and presumed to 

belong with them, it is assumed that this fern 

was probably of large size, but the direct 

evidence is only sufficient to say that it is at 

least bipinnatified. Under the circumstances 

measurements are of comparatively little value, 

though it may be stated that the pinnules 

range from 5 or 6 to 10 centimeters or more in 

length and from 8 to 18 millimeters in width. 

Occurrence: Frontier formation, about 1 mile 

east of Cumberland, Wyo. , Collected by A. C. 

Veatch in 1906. 
84 SHORTER CONT~IBUTIONS TO GENERAL GEOLOGY, 1917. 

Asplenium occidentale Knowlton, n. sp. 

Plate XXXI, figures 2-5. 

Although this form is represented by a large 

number of specimens, they are all so fragmentary and disconnected that it is impossible 

to gain an adequate conception of the frond as 

a whole. Under the circumstances it seems 

best simply to figure a number of the bestpreserved fragments and describe them as fully 

as possible, but to leave to the future its 

definite allocation. It was evidently a fern 

of considerable size, as may be seen from the 

example shown in figure 4. This has a preserved length of 7 centimeters and a width of 

3.5 centimeters but was probably considerably 

larger. The margin is undulate-lobed and has 

a few fine, sharp teeth. The apex in other 

specimens is shown to be strongly toothed. 

The nervation consists of a very stout midvem 

and strong veins that arise at an angle of 

probably 40° but curve outward until they are 

nearly at right angles to the midvein. The 

veins fork usually very close to the midvein 

and once or twice above. 

The specimen shown in figure 2 consists of 

two pinnules attached to a minute piece of 

the rachis. Each is rounded on the lower side, 

so that they produce together a deeply heartshaped base. The tip of the left-hand pinnule 

shows the strong teeth above mentioned. 

. In figure 5 two examples are shown; the 

lower is about the size of the one last described, 

the upper much smaller. The margin of the 

upper one is strongly undulate-toothed, becoming in the upright segment almost lobed. 

The nervation is of the same character as that 

in the large· example (fig. 4), described above, 

except that there is usually only one fork in 

the nerves and this is near the midvein. 

On account of the uncertainty attending 

the assignment of this form it is G>bviously unwise to attempt comparisons with either living 

or fossil species. It is placed in the genus 

Asplenium on the ground of its resemblancefancied or real-to the living Asplenium hemionites Linne, but more complete material will 

·be necessary before its status can be fixed. It 

is believed, however, that enough of it is here 

described and figured to permit its subsequent 

recognition, not only in the Frontier formation 

but elsewhere. 

Occurrence: Frontier formation, 1 mile east 

of Cumberland, Wyo. Collected by F. H. 

Knowlton and T. W. Stanton in 1908. 

, Family SCHIZAEACEAE. 

Anemia fremonti Knowlton, n. sp. 

Plate XXXI, figure 6; Plate XXXII, figures 1-3. 

Outline of whole front not known; stipe 

long, slender, dichotomous; frond bipinnate, 

possibly tripinnate; pinnae narrowly deltoid; 

pinnules arising at an acute angle, linear-lanceolate, sessile and decurrent or lower ones nearly 

free; pinnules cut, especially near the base, . 

into deep, sharp-toothed, entire, forwardpointing lobes, which decrease ap~cally so that 

the terminal fourth is entire or merely crenulate; middle and upper pinnules becoming 

more and more entire toward the apex, which 

is only crenulate; nervation rather sparse, at a 

very acute angle, nerves once or twice forked; 

fertile frond not found. 

This species is represented by a large number 

of specimens, but unfortunately all are so fragmentary that it is impossible to make out the 

shape and size of the whole frond. Some evidence to show that the frond was very large 

and several times compounded is afforded by 

the presence of certain fragments disposed in 

such a way on the matrix as to suggest the 

possibility of their organic connection, but no 

such union has been seen. A dichotomous 

branching of the slender rachis, such as is 

shown in figure 3, is all the branching that has 

been observed. The longest segment of rachis 

observed (fig. 3) is 6 centimeters long but was 

certainly considerably longer when perfect. 

The best-preserved pinna, shown in figure 1, is 

14 centimeters long, of which ~t least 2 centimeters is made up of secondary rachis. It is 

approximately 6 centimeters broad between the 

tips of the lower pinnules. The manner and 

extent of the marginal cutting of the pinnules 

is so well shown in the figure that it is not necessary to describe them at greater length. 

This species is exceedingly close to Anemia 

subcretacea (Saporta) Gardner and Ettingshausen/ a species that was described from 

~5pecimens obtained in the Eocene travertines · 

of Sezanne and was subsequently found to be 

abundant in the Eocene of Bournemouth, England. The present form appears to differ 

slightly in its broader pinnae, generally less 

sharply cut pinnules, and more erect nervation, but at best the difference is not great. 

Gardner and Ettingshausen referred Lesquereux's Gymnogramma haydenii,2 from the divide 

1 Gardner, J. S., and Ettingshausen, Constantin von, Monograph of 

the British Eocene flora, vol. 7, p. 45, pls. 8, 9, 1880. 

11 U.S. Geol. Survey Terr. Rept., vol. 7, p. 5·9, pl. 5, figs. 1-3, 1878. 
A FOSSIL FLORA FROM THE FR.ONTIER FOR.MATION OF SOUTHWESTERN WYOMING; 85 

between the headwaters of Snake River and 

Yellowstone Lake, to their Anemia subcretacea, 

and in this reference Lesquereux concurred. 

The specimen shown in figl{re 3 of Lesquereux's 

plate is considerably like the specimens from 

Cumberland, but those shown in the other fig~ 

ures are quite different. 

At one time Newberry was of the opinion 

that he had found Anemia subcretacea at a 

number of localities, as Point of Rocks, Wyo. 

(Montana), Erie, Colo. (Laramie), and Bellingham Bay and Carbonado, Wash. (Eocene), but 

in his formal report 1 he inclined to regard them 

as representing a well-marked, robust variety. 

This work was edited by Hollick, who substituted the name Anemia perplexa for the reason 

that A. subcretacea was considered nomenclatorially untenable. The specimens figured 

by Newberry are very unlike the present 

species, and furthermore, it would seem to be 

wise not to regard them as identical with the 

European form. 

A fine large species of Anemia from the 

Raton formation of Colorado is described by 

me in a paper now in press/ but it is quite 

different from Anemia gracillinea. 

Fragmentary specimens of Anemia have 

been found at many localities in the Rocky 

Mountain region, ranging in age from early 

Montana to Laramie, but none of them appear 

to agree very closely with the present species. 

Occurrence: Frontier formation, 1 mile east 

of Cumberland, Wyo. Collected by F. H. 

Knowlton and T. W. Stanton in 1908. 

Family EQUISETACElE. 

Equisetum sp. 

Plate XXXIII, figure 6. 

The collection made near Cumberland by 

Veatch contains a single specimen with its 

counterpart that apparently represents the 

underground stem of an Eq_uisetum. It is 

about 9 centimeters long, has a maximum 

diameter of nearly 1 centimeter, and is more or 

less constricted or cut up into short segments 

10 to 15 millimeters in length. It is irregularly 

ridged or wrinkled longitudinally but otherwise 

has no marks or features of diagnostic value. 

I Newberry, J. S., The later extinct floras of North America: U. S 

Geol. Survey Mon. 25, p. 4, 1898. 

2 Lee, W. T., and Knowlton, F. H., Geology and paleontology of the 

Raton Mesa and other regions in Colorado and New Mexico: U. S. 

Geol. Survey Prof. Paper 101, p. 285, pl. 54, fig. 2 (in press) . 

• 

Beyond the fact of attesting the presence of 

vegetation of this type in the Frontier formation this specimen is of little value, as it could 

probably not be recognized or discriminated if 

found elsewhere. For this reason there is little 

use jn attempting comparisons with described 

species, though incidentally it may be compared 

as being similar in type to Eq_uisetum prelaevigatum Cockerell (E. laevigatum Lesquereux3), 

from the Denver formation of Colorado. 

Occurrence: Frontier formation, north side 

of Little Muddy Creek, about 1 mile east of 

Cumberland, Wyo., in sec. 29, T. 19 N., R. 116 

W. Collected by A. C. Veatch in 1905. 

Family SMILACElE. 

Smilax? coloradensis Knowlton, n. sp. 

Plate XXXIII, figure 1. 

Leaf small, membranaceous, regularly elliptical, abruptly rounded below to a very slightly 

heart-shaped base, apex destroyed but apparently rather obtusely pointed; three-ribbed 

from base, the midrib slightly the stronger, 

lateral ribs passing up nearly or quite to the 

apex, each with several branches on the outside 

which join and produce a semblance of an additional rib on each side; no secondaries observed 

on the midrib, but a few strong nervilles between the ribs; fine nervation not retained. 

The specimen figured is all that was found 

of this form. It is about 5 centimeters long 

and 3.5 centimeters wide. The nervation is so 

poorly preserved that hardly anything but the 

main ribs is retained. It is for this reason that 

the generic reference has been questioned, 

though it has the size, shape, thickness, and, so 

far as can be made out, the essential nervation 

of certain living forms of the genus. More and 

better material will be necessary to settle the 

matter fully. 

Occurrence: Frontier formation, dump of · 

mine No. 1, Cumberland, Wyo. Collected by 

F. H. Knowlton August 5, 1908. 

Family MYRICACElE. 

Myrica nervosa Knowlton, n. sp. 

Plate XXXIV, figure 1. 

In the small collection obtained about 1! 

miles south of Cumberland, Wyo., there are a 

number of fragmentary leaves of Jfyrica. The 

a Lesquereux, Leo, U.S. Geol..oSurvey Terr. Rept., vol. 7, p. 68, pl. 6, 

fig. 6, 1878. 
86 SHORTER CONTRTBUTIONS TO GENERAL GEOLOGY, 1917. 

nervation is very distinct and characteristic, 

and although the specimens are so much broken 

that the size and shape can not be fully made 

out, it seems best to put the form on record so 

that it may be looked for in the future. 

This species is narrowly lanceola'te, probably 

acuminate at base and apex, ·and has perfectly 

entire margins. The length was apparently 8 

or 9 centimeters and the width about 2 centimeters. · The leaf substance is thick and leathery, as shown by the wrinkled appearance of 

the leaves. rrhe midrib is exceedingly strong. 

The secondary nervation is thin and irregular, at an angle of 50° or more, much curved 

upward, each principal nerve arching just outside the margin and producing an intramarginal 

"stitch." There are numerous intermediate 

.secondaries which pass up and join the bows of 

the larger nerves, or disappear in a network of 

nervilles. The finer nervation produces a network of irregular areas. 

This species is, in a way, of the type of Myrica 

torreyi Lesquereux, of the Montana group and 

slightly younger horizons. It differs markedly 

from that species, however, in its smaller size, 

entire instead of serrate margins, and secondaries of two sizes, the larger ones forming the 

intramarginal vein. The nervation is also at a 

more acute angle than in M. torreyi. 

09currence: Frontier formation, 1l miles 

south of Cumberland, Wyo., in theSE. i sec. 6, 

T. 18 N., R. 116 W. From same horizon as 

plant beds 1 mile east of Cumberland. Collected by T. W. Stanton September 1, 1913. 

Family SALICACEAE. 

Salix cumberlandensis Knowlton, n. sp. 

Plate XXXVIII, figure 3. 

Leaf firm in texture, lanceolate, 8 centimeters 

long, 2 centimeters wide, abruptly rounded 

below to the short, thick petiole, broadest at 

and below the lower third of the blade, whence 

it is gradually narrowed to the slenderly acuminate apex; margin finely and evenly crenate 

throughout; midrib very thick, especially below; 

secondaries strong, 16 or more pairs, alternate, 

emerging at an angle of 30° or 35°, much curved 

upward anQ_ apparently effused near the margin; 

finer ner:vation not retained. 

This handsome little species is represented 

only by the very perfect example figured. It 

is well marked by its narrowly oblong-lanceolate 

outline, abruptly rounded base, finely crenulate 

margin, and numerous strong, apparently 

camptodrome secondaries. 

Occurrence: Frontier formation, 1! miles 

south of Cumberlang, Wyo., in theSE. ! sec. 6, 

T. 18 N., R. 116 W. From same horizon as the 

plant beds 1 mile east of Cumberland. Collected by T. W. Stanton September 1, 1913. 

Salix frontierensis Knowlton, n. sp. 

Plate XXXV, figure 4a. 

Leaf small, apparently rather thick, elliptical lanceolate, broadest at ~ point below the 

middle, whence it rounds rather abruptly to 

the short, thick petiole; apex destroyed but 

apparently acuminate; margin perfectly entire; midrib very strong for a short distance, 

then much thinner; secondaries 10 or 12 pairs, 

very thin and delicate, curved upward, camptodrome; finer nervation obscure. 

The little leaf figured is unfortunately the 

only one of this kind noted in the collection. 

It was about 3.5 centimeters long and 1.3 centimeters wide; the petiole is about 3 millimeters long. 

Occurrence: Frontier formation, 1~ miles 

south of ·Cumberland, Wyo., in the SE. i sec. 

6, T. 18 N., R. 116 W. From same horizon 

as plant beds 1 mile east of Cumberland. Collected by T. W. Stanton S~ptember 1, 1913. 

Family FAGACEAE. 

Quercus stantoni Knowlton, n. sp. 

Plate XXXIII, figures 2-4. 

Leaves membranaceous,- rather broadly lanceolate, long, wedge-shaped at base, much 

more abruptly narrowed above to an obtusely 

acuminate apex; margin entire below, coarsely 

few-toothed or lobed above, the teeth separated 

by shallow sinuses, sharp, mucronate-tipped; 

petiole strcmg, at least 1.5· centimeters long; 

midrib very strong below, not much thinning . 

above; secondaries about 10 or 12 pairs, mainly 

alternate, at an angle of 45°, running nearly 

straight to the teeth below, slightly curved upward above; nervilles numerous, strong, irregular, finer nervation forming a coarse, irregularly quadrangular network. 

This species is represented by nearly a dozen 

specimens, none of ~hich, however, is complete. The length, including the petiole, must 

have been at least 10 or 12 centimeters and 

the width between 3 and 4 centimeters. The 
A FOSSIL FLORA FROM THE FRONTIER :E'ORMATION OF SOUTHWESTERN WYOMING. 87 

species is well marked by the long, wedgeshaped base, more obtuse apex, and coarse 

marginal teeth or lobes, which are all mucronate-tipped, thus indicating that it is a member of the black-oak group. In figure 3 is 

shown a cluster of three leaves that were pro bably attached to the same branch, though the 

actual union is not shown. The best preserved 

of these gives a very satisfactory view of the 

lower half of the blade, with its strong petiole 

and mucronate teeth. In figure 2 is shown a 

very complete apical portion of a leaf of the 

same size as the one in figure 3. The basal 

portion of another well-preserved leaf is seen 

in figure 4. 

Among fossil species of Quercus the present 

species is rather closely related apparently to a 

number from the Senonian of Haldene, Westphalia, as described by Hosius and Von der 

Marck.1 It is perhaps nearest to Quercus formosa, from which it differs in being broader 

and in having larger, sharper, mucronatetipped teeth. From Quercus sphenobasis it 

differs in its fewer, larger teeth and fewer secondaries. 

Occurrence: Frontier formation, 1~ miles 

south of Cumberland, Wyo., in the SE. l sec~ 

6, T. 18 N., R. 116 W. From same horizon as 

plant beds 1 mile east of Cumberland. Collected by T. '-l{. Stanton September 1, 1913. 

Family MORACEAE. 

Ficus fremonti Knowlton, n. sp. 

Plate XXXIV, figures 4-6; Plate XXXV, figures 4c, 5. 

Glossopteris phillipsii? Brongniart . .. Hall, in Fremont, 

op., cit., Appendix B, p. 305, pl. 2, figs. 5, 5a-c. 

Lesquereux, U. S. Nat. Mus. Proc., vol. 11, p. 37, 

1888. 

Leaves small, very thick and coriaceous, 

narrowly lanceolate, broadest below the middJe, 

whence they narrow below "to a rather long, 

wedge-shaped base and· above to a very long, 

narrow acuminate apex; margin perfectly 

entire; petiole short (1 centimeter), relatively 

strong; midrib very stro1!-g; secondaries immersed in the substance of the leaf and indjstinct, numerous, at an acute angle, camptodrome; finer nervation obscure. 

This form is represented by 25 or more specimens, few of which are perfect. It is a small, 

very narrowly lanceolate leaf, 6 to 8 or 9 cen ti1 Hosius, A., and Von der Marek, W., Flora der westf3Jischen Kriede. 

formation: Palaeontographica, vol. 26, p. 164 [40], pl. 31, fig. 81, 1880. 

meters long and 1 to 2 centimeters wide, with a 

petiole 1 centimeter or slightly over in length. 

I't is especially distinguished by its long, narrowly acuminate apex. 

The species here called Ficusfremonti has had 

a most interesting history. It was first collected by Fremont in 1843 and was identified by 

Hall as Glossopteris phillipsii, for the reason, 

he adds, that Brongniart's species afforded ''the 

only description and figure accessible to me to 

which this fossil bears any near resemblance." 

Examination of Brongniart's figure 2 shows that 

this form certainly does resemble it so far as 

size and shap.e go but is totally different in 

nervation. Glossopteris phillipsii has of course 

a pteroid nervation with close, parallel, forking veins, but the secondary nerves in the 

leaves here described, as may be seen from the 

figures, are distinctly those of a dicotyledon. 

Fortunately, two of the original Fremont 

specimens (Hall's figs. 5 and 5b) are preserved 

in the United States National Museum and are· 

shown here(Pl. XXXIV, fig. 6; Pl. XXXV, fig. 

5). These leaves passed under Lesquereux's eye, 

and although he lists them under Glossopteris 

phillipsii he makes the following statement: 3 

''This is remarkably similar in form of leaves 

and nervation to Glossochlamys transmutans 

Gardner and Ettingshausen (British Eocene 

flora, p1. 3, fig. 3; pl. 12, fig. 8). The specimens of Fremont show indistinctly nervilles 

between the lateral nerves composing irregular, 

square meshes." 

The figures of Giossochlamys transmutans 

given by Gardner and Ettingshausen show that 

to an intents and purposes this form is a dicotyledon, and in fact these authors admit that 

Saporta, whom they consulted, objected to the 

reference of this fossil to a fern, and Heer 

stated flatly that "it is not a fern, but a leaf of a 

dicotyledon." There can be absolutely no 

question about it-the leaves under consideration belong to a dicotyledon and have nothing 

to do with ferns. 

It was largely on the basis of Hall's identification of these leaves as Glossopteris phillipsii 

that the beds were referred to the Jurassic. 

On this point Hall says: "The geological position of the fossil is so well ascertained to be the 

schists of the upper part of the Oolitic period 

2 Brongniart, Adolph, Histoire des vegeteaux fossiles, p. 225, pl. 51 bis, 

fig. 2, 1828. 

3Lesquereux, Leo, Recent determinations of fossil plants from Kentucky, Louisiana, * * * : U. S. Nat. Mus. Proc., vol. 11, p. 37, 1888. 
88 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1917. 

that, relying upon the evidence afforded by a 

single species, we might regard it as a strong 

argument for referring all the other specimens 

to the same geological period." 

region, it might well be discarded. It simply 

calls attention to the presence of a large leaf 

whose more definite placing must be left to 

the future. 

Occurrence: Frontier formation, mine No. 1, 

half a mile east of Cumberland, Wyo. Collected by T. W. Stanton and F. H. Knowlton 

in 1908. ' 

Ficus? sp. 

Plate XXXI'V,.figures 2, 3. 

Ficus fremonti agrees very well in shape with 

Ficus proteoides Lesquereux/ from the Dakota 

sandstone of Kansas, but the latter is a much 

larger .leaf and has a more open nervation. 

In shape, size, and nervation it · is even closer 

to Ficus Zanceolata acuminata Ettingshausen, as 

figured by Lesquereux,2 from the Dakota sandstone of Kansas. This species, however, is The collection obtained half a mile east of 

somewhat longer and broader and has the Cumberland contains a number ·of narrow 

nervation more regular and at a less acute leaves that are included here only on the 

angle of divergence. ground that it seems desirable to enumerate 

As stated on page 80, one of the original everything known from this general region. 

specimens figured by Hall sh'Owed on one side of They are preserved in a coarse-grained sandthe leaf round bodies which have now been stone that has obscured most of the characteridentified as the egg mass of an insect, prob- istic featu~es-in fa~t, about all t~at c~n _be 

ably a micro1epidopterous insect. It is shown made out IS the outhne and ~he th1ck m1dr1b. 

in figure 5 of Plate XXXVI. · They are narrowly lanceolate leaves that are 

Occurrence: Frontier formation about 1 rather abruptly rounded to· the base and 

mile east of Cumberland, Wyo. ' Originally appare~tly long acumin~te at the apex. The 

collected by J. C. Fremont August 19, 1843; len~th IS about 10 centrmeters and the width 

subsequently found at or near the same place a httle over 2 centimeters. The midrib is 

by F. H. Knowlton and T. W. Stanton in 1908. strong, and there is sollle slight indication of 

Ficus? sp. 

. Plate XXXV, figure 1. 

A small collection made from a rather coarsegrained shaly sandstone about 300 feet above 

the main plant locality east of Cumberland 

contains a number of fragmentary leaves that 

seem to belong to Ficus, but there are little 

more than outlines to afford basis for a judgment. The leaf shown in figure 1 is one of the 

best preserved of these specimens. It is 

ovate, with an abrttptly rounded truncate 

base, probably obtusely acuminate apex, and 

entire margins. The length was about 10 or 11 

centimeters and the width nearly 5 centimeters. 

Even the primary nervation is so obscure that 

it is made out with difficulty. It consists of a 

fairly strong midrib and apparently a strong 

rib or secondary arising near the base and 

passing up for a long distance, but it is more 

or less uncertain. 

This form is so obscure that it is of little 

value, and except for the desirability of 

enumerating all the plants present in this 

1 Lesquereux, Leo, Flora of the Dakota group: U.S. Geol. Survey Mon. 

17, p. 7i, pl. 12, fig. 2, 1892. 

'Idem, p. 85, pl. 13, fig. 4. 

secondary branches, but they are very uncertain. 

This form might be compared with a number 

of long, narrow-leaved species of Ficus or 

certain entire-leaved species of Salix, 'but 

absence of essential features makes definite 

comparisons of little value. 

Occurrence: Frontier formation, half a mile 

east of Cumberland, Wyo. Collected by F. H. 

Knowlton and T W. Stanton August 5, 1908. 

Family LAURACEAE. 

Cinnamomum hesperium Knowlton, n. sp. 

Plate XXXVIII., figure 2. 

Leaf semicoriaceous or finer in texture, narrowly lanceolate, broadest near the middle, 

whence it narrows in almost the same degree 

to both base and apex; length 7 centimeters 

including the petiole, which is about 8 millimeters long; width about 13 millimeters; 

petiole relatively short, stout; midrib very 

strong below, becoming much thinner in the 

upper half of the blade; lateral ribs at an 

acute angle, arising at a point about 5 millimeters above the base of the blade, passing up 

and joining the lowest pair of secondaries 

near or above the middle, each with two or 
A .FOSSIL FLORA FROM THE FRONTIER FORMATION OF SOUTHWES,TERN WYOMING. 89 

three secondary branches on the outside; 

secondaries on the midrib three pairs, alternate, 

lowest arising far below the middle of the blade, 

arching upward and runniug along near and 

gradually lost in the margin; nervilies obscure, 

apparently close, parallel, unbroken, and at 

right angles to the ribs and secondaries. 

This species is represented only by the 

exan1ple figured, which fortunately is practically perfect, so that its characters can be made 

out with certainty. It is with much hesitation 

described as new. At one time it was identified ·with a specimen from Hodges Pass, 

Wyo., described and figured by Ward 1 under 

the name Ginnamomum Zcinctolatum (Unger) 

Heer but later given the name G. wardii 

Knowlton 2 on the ground that it was not 

conspecific with the European species. Except 

in the matter of size these two leaves are 

undoubtedly close. Thus, G. wardii is 15 

centimeters long and 2.5 centimeters wide, 

G. hesperium is 6 centimeters long and 1.4 

centimeters wide. There are also other slight 

differences. In G. wardii the base is more 

obtuse and rounded, the lateral ribs at a less 

acute angle and without outside se0ondaries, 

and the secondaries on the midrib are closer 

and more numerous, but these are all comparatively unimportant divergences that might 

possibly break down if a series was available for 

comparison instead of a single leaf of each form. 

The leaf found near Cumberland, Wyo., is 

also strikingly similar in size, shape, and general appearance to Ginnamomum salicifolium 

Staub, 3 from the well-known Tertiary beds at 

Sotzka, in Styria, but here again there are 

noticeable slight differences. Thus there are 

no outside secondaries on the lateral ribs, and 

the secondaries on the midrib are more numerous and confined to the upper half or upper 

third of the leaf. 

Ginnamomum salicifolium was segregated by 

Staub from G. lanceolatum (Unger) Heer, on 

the basis of its generally narrower shape, 

higher secondaries, etc., but the difference is 

not great. 

The geologic horizon at which the leaf G. 

wardii was found is more or less in doubt. The 

1 Ward, L. F., Synopsis of the flora of the Laramie group: U. S. Geol. 

Survey Sixth Ann. Rept., pl. 46, fig. 12, 1886. 

~Knowlton, F. H ., A catalogue of the Cretaceous and Tertiary plants 

of North America: U.S. Geol. Survey Bull.152, p. 69, 1898. 

a Staub, Moriz, Die Geschichte des genus Cinnamomum, p. 65, pl. 12, 

figs. 7-14, 1905. 

specimen was supposed by Ward to be from 

beds of Laramie age as then interpreted, but 

the work of Veatch appears to place it in the 

upper part of the Adaville formation of the 

Montana group, or nearly 10,000 feet above the 

horizon which supplied the Cumberland leaf. 

The species was not found in any of the recent 

collections made in this general region. 

Although these two species (G. wardii and 

what is here called G. hesperium) are undoubtedly close together, the best that can be done 

under the circumstances, considering the differences in size and nervation already pointed 

out, as well as the apparent disparity in age, 

is to regard them as distinct until additional 

material can be obtained. 

Occurrence: Frontier formation, 1! miles 

south of Cumberland, Wyo., in the SE. t sec. 

6, T. 18 N., R. 116 W. Same bed as plant 

locality 1 mile east of Cumberland. Collected 

by T. W. Stanton September 1, 1913. 

Cinnamomum? sp. 

Plate XXXV, figure 2. 

There are in the collection several very 

fragmentary leaves that appear to belong to 

the genus Ginnamomum, though they are 

obscure at critical points. The one figured is 

ovate-lanceolate and has a rounded wedgeshaped base and an acuminate apex. The 

length is 9 centimeters and the width a little 

less than 5 centimeters. The midrib is strong; 

the lateral ribs are somewhat thinner and pass 

up nearly to the apex. There are several 

secondary branches on the outside of the lateral 

ribs, but otherwise the nervation can not be 

made out. 

Occurrence : Frontier formation, half a mile 

east of Cumberland, Wyo. Collected by F. H. 

Knowlton and T. W. Stanton August 5, 1908. 

Family PROTEACEAE. 

Dryandroides lanceolata Knowlton, n. sp. 

Plate XXXIV, figure 7. 

Leaves coriaceous, narrowly lanceolate, base 

not seen but apparently rather abruptly narrowed to a short, wedge-shaped basal portion, 

prolonged above into a very long, acuminate 

apex which is minutely emarginate at the tip; 

margin in lower and middle portions distinctly 

toothed, the teeth sharp 'pointed, separated by 

very shallow sinuses; margin in upper portior.. 
90 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1917. 

undulate and finally entire; midrib very strong; 

secondaries numerous (probably at least 15 

pairs), alternate, at an angle of 35° or 40°, 

considerably curved upward, entering the teeth 

or arching and each joining the secondary 

next above and sending a short, outside branch 

to the tooth; secondaries in the narrowed, 

entire apical portion of the blade arching 

upward for a considerable distance and disappearing in or near the margin; nervilles 

numerous, mainly broken and at right angles 

to the secondaries. 

The portions of the two leaves shown in 

figure 7 are all that has been observed of this 

well-marked form. It is not possible to ascertain the exact length, but it could hardly have 

been less than 11 or 12 centimeters. The 

greatest width is slightly less than 2 centimeters. 

The large segment referred to this species is 

certainly very oaklike in appearance, but the 

long, slenderly acuminate apical portion is 

much less so, and it seems best referred to the 

genus Dryandroides. It is, for instance, very 

similar to D. quercinea V elenovsky, 1 from the 

Cretaceous of Bohemia. It is, however, . a 

larger, longer leaf, with a narrower apical 

portion, fewer lower teeth, and fewer secondaries at a more acute angle. 

Dryandroides quercinea has been reported by 

Hollick 2 from the Magothy formation at Gay 

Head, Marthas Vineyard, Mass., but this reference depends on two fragmentary leaves and is 

open to some question. 

The only other species of Dryandroides 

tentatively accepted as North American was 

described by Lesquereux 3 under the name 

Quercus cleburni. It comes from Black Buttes, 

Wyo., and is very different from the present 

form; in fact, it is doubtful if it should be 

placed in Dryandroides. 

Occurrence: Frontier formation, 1! miles 

south of Cumberland, Wyo., in the SE. 1- sec. 

6, T. 18 N., R. 116 W. From same horizon as 

plant bed 1 mile east of Cumberland. Collected by T. W. Stanton September 1, 1913. 

1 Velenovsky, J., Die Flora der bohmischen Kreideformation: Beitr. 

PaUi.ontologie Oesterr.-Ungams u. des Orients, Band3, Heft 1, p. 33 (8), 

pl. 10 (2), 1883. 

2 Hollick, Arthur, The Cretaceous flora of southern New York and 

New England: U. S. Geol. Survey Mon. 50, p. 60, pl. 8, figs. 18, 19, 190(). 

a Lesquereux, Leo, U.S. Geol. Survey Terr. Rept., vol. 7, p. 154, pl. 

20, fig. 2, 1878. 

Family RANUNCULACEAE? 

Dewalquea pulchella Knowlton, n. sp. 

Plate XXXVI, figures 1-3; Plate XXXVII, figures 1-3. 

Leaves of medium or small size, palmately 

decompound, the segments usually five but 

occasionally six in number; petiole extremely 

long, much longer than the longest foliar segment, splitting at top into two nearly equal 

branches, one of which usually gives rise to 

two and the other to three segments, though 

the middle segment in a five-parted leaf may 

be nearly or quite free; segments all narrowly 

linear-lanceolate, of approximately the same 

size, the other segments slightly inequilateral, 

the middle one in some leaves slightly smaller 

than the others, all long and very narrowly 

wedge-shaped at base, acuminate at apex; 

margin of segments usually entire' for a short 

distance at the base, thence strongly and sharply 

serrate; midrib strong, straight; secondaries 

obscure owing to the thickness of the leaf substance, numerous, apparently subopposite, at 

an angle of about 40°, slightly curved upward, 

all but the lower ones craspedodrome and ending in the marginal teeth; finer nervation not 

retained. 

This splendid species is represented by nearly 

twenty specimens, six or seven of which have 

been figured. In none of the specimens are all 

the segments preserved entire, but some are 

nearly perfect, and hardly any of them. is so 

fragmentary as not to show the manner in 

which the segments arise from the top of the 

petiole. Apparently in a majority of the 

leaves of this genus from other areas, as 

described, the segments are so broken and 

detached that it becomes a matter of difficulty 

to interpret them satisfactorily. The leaves 

here described, however, are so well preserved 

that there can be absolutely no question as to 

their being congeneric with the type and typical species from European deposits, from 

which the genus was first made known. 

The present leaves are rather small compared 

with those of typical members of the genus. 

None of the segments exceed 8 or 9 centimeters 

in length and 1.5 centimeters in width, and 

apparently most of them are only 6 or 7 centimeters long and 1 centimeter or less in width. 

The segments are cut so deeply that they are 
A FOSSIL FLORA FROM THE FRONTIER FORMATION OF SOUTHWESTERN WYOMING. 91 

almost free, and there is very little evidence of 

their being unequal-sided at the base. In only 

one specimen, that shown in Plate XXXVI, 

figure 3, is there six seg1nents, all the remainder 

having five very symmetrically spaced divisions. 

The petiole, which is preserved entire in several specimens, is extremely long and slender. 

In the leaf shown in Plate XXXVII, figure 2, 

for instance, it is nearly 5 centimeters long and 

probably exceeds the length of the segments. 

The average length is about 4 centimeters. 

This species is very closely related to Dewalquea insignis Hosius and Von cler Marek, 1 from 

the Upper Senonian of Westphalia-so closely 

related, in fact, that it would perhaps do no 

great violence to call them the same. 'l'he 

present form differs from the Westphalian 

species in its generally sma1ler size, longer petiole, usually fewer segments with much larger, 

sharper teeth, and, so far as can be made 

out, fewer, more curved secondaries. These, 

however, are all minor differences that might 

well be covered by individual variation; but 

in consideration also of the difference in geo-

. graphic and stratigraphic position, it is perhaps 

as well to consider the Wyoming form under 

another name. 

Dewalquea insignis was recorded by Heer 2 

from both the Atane and Patoot beds of 

Greenland, and by Hollick 3 from the Cretaceous of Staten Island, but as Berry 4 has recently pointed out, ''both these determinations 

are based upon fragments of single leaves and 

are, in the writer's judgment, entirely untrustworthy." 

The genus Dewalquea was established by 

Sa porta and Marion 5 in 187 4, and was based on 

two species (Dewalquea lwldemiana and D. 

aquisgranensis) from the Senonian of W estpha-

~ lia, sent to them by Debey under the manuscript names Araliophyllum and Grevillea, and 

one (D. gelindensis) collected by themselves 

from the Paleocene of Gelinden, Belgium. 

Since that date 10 additional species, all from 

1 Hosius, A., and Von der Marek, W., Die Flora der westfiUisc:hen 

Kreideformation: Palaeontographica, vol. 26, p. 172 (48), pl. 32, figs. 

111- 113; pl. 33, fig. 109; pl. 34, fig. 110, 1880. 

z Heer, Oswald, Flora fossilis arctica, vol. 6, Abt. 2, p. 86, pl. 25, fig. 7, 

pl. 33, figs. 14-16, 1882; vol. 7, p. 37, pl. 58, fig. 3; pl. 62, fig. 7, 1883. 

3 Hollick, Arthur, The Cretaceous fiora of southern New York and 

New England: U.S. Geol. Survey Mon. 50, p. 106, pl. 8, fig. 24, 1906. 

4 Berry, E. W., The Upper Cretaceous and Eocene fioras of South 

Carolina and Georgia: U S. Geol. Survey Prof. Paper 84, p. 42, 1914. 

o Saporta, Gaston de, and Marion, A. F., Essai sur l'etat de la vegetationa l'epoque des marnes heersiennes de Gelinden: Acad. roy. Belgique Mem. cour. et des sav. etrang., vol. 37, p. 55, 1874. 

the Upper Cretaceous, have been named by 

different authors. Of these one (D. gronlandica 

Heer) is from the Patoot and Atane beds of -

Greenland, two (D. dakotensis Lesquereux and 

D. primordial is Lesquereux) from the Dakota 

sandstone of Kansas and Minnesota respectively, one (D. trijoliata Newberry) from the 

Raritan formation of New Jersey, and one 

(D. smithi Berry) from the Tuscaloosa formation of Alabama and the Black Creek formation 

(Middendorf arkose member) of South Carolina. 

Of the Greenland and American species all 

but one (D. smithi Berry) 6 have leaves with 

only three segments or leaflets and are very 

unlike D. insignis or D. pulchella. The species 

described by Berry is a very handsome one; 

the leaves have five segments which are from 

8 to 16 centimeters in length and sharply 

serrate, and the lateral segments are curiously 

unequal-sided at the base. This is undoubtedly- a Dewalquea, but it is very distinct from 

the species here described. 

The systematic affiliations of the genus 

Dewalquea are still more or less obscure. A8 

may be inferred from the names suggested by 

Debey, he regarded it as belonging either in 

the Araliaceae or in the Proteaceae, but when 

Saporta and Marion established the genus they 

took occasion to review the matter with great 

care, and after comparing it with several genera 

such as Aralia, Ampelopsis, and Arisaema (a 

monocotyledon of the family Araceae) concluded that it had the greatest affinity with 

the tribe Helleboreae of the family Ranunculaceae. The Helleboreae in the living flora 

are herbaceous, but Saporta and Marion state 

that the presence of a Cretaceous or early 

Eocene shrubby ancestor would be quite in 

accord with the evolutionary history of some 

other groups. 

Although these authors pointed out the 

reasons opposing the reference of Dewalquea 

to the Araliaceae, such a reference seems to 

the writer to be entitled to further consideration. It .is, for instance, difficult to escape 

the conviction that certain leaves from the 

Dakota sandstone referred to Aralia may well 

have been ancestral to leaves of Dewalquea 

of the type of D. insignis, D. pulchella, etc. 

Take, for example, the species described by 

6 Berry, E. vV., op. cit., p. 41, pl. 8, figs. 3-9 (restoration, fig. 1 in 

text). 
92 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1917. 

Lesquereux 1 as Aralia wellingtoniana. This 

is a medium-sized leaf with five deeply cut, 

sharply serrate lobes in which the secondary 

nervation is close, parallel, and craspedodrome 

in the upper portions. If the separation of 

these lobes were continued .a short distance 

until the lobes were nearly or quite free, 

though still showing the method of origin from 

the branches of the petiole, a palmately decompound leaf would result that seemingly 

would be a Dewalquea. A further step in this 

process is shown in one of the Dakota leaves 

figured by Lesquereux 2 under the name 

Aralia saportanea var. deformata. Here the 

central lobe is reduced and cut almost to the 

base. The lateral lobes are also deeply cut 

and the margin· below the major fork of the 

petiole is reduced to a very narrow web. A 

very slight continuation of this lobing would 

make these segments free or at least cut them 

to the branches of the petiole. Hence it seems 

to the writer a less violent assumption to 

derive the decompound, coriaceous-leaved 

species of Dewalquea from an equally coriaceous deeply lobed Aralia of. the type above 

indicated than to suppose them to be the Cretaceous ancestors of the living herbaceous 

Helleboreae. 

Occurrence: Frontier formation, 1 mile east 

of Cumberland, Wyo., in sec. 29, T. 19 N., 

T. 116 W. Collected by A. C. Veatch in 

August, 1905. 

Family ARALIACElE. 

Aralia veatchii Knowlton, n. sp. 

Plate XXXVI, figure 4; Plate XXXVII, figure 4; Plate 

XXXVIII, figure l; Plate XXXIX. 

Aralia cf. A. saportana Lesquereux. Knowlton, in Veatch, 

Am. Jour. Sci., 4th ser., val. 21, p. 459, 1906. 

Outline of whole leaf not known, but clearly 

a leaf of large size ·and firm texture; palmately 

three-lobed and, presumably at least, fivelobed, the central lobes lanceolate, slenderly 

acuminate at apex, slightly contracted at the 

base; margin conspicuously toothed, the teeth 

sharp pointed, separated by shallow sinuses; 

lateral lobes at an angle of about 45° with the 

middle lobe and separated from it by a deep 

narrow sinus, margin entire below, becoming 

toothed above like the central lobe; nervation 

· of lobes consisting of a very strong midrib and 

12 or 14 pairs of fairly strong secondaries which 

1 Lesquereux, Leo; The flora of the Dakota group: U. S. Geol. Survey 

Mon. 17, pl. 22, fig. 2, 1891. 

2 Idem, pl. 23, fig 1. 

emerge at an angle of 45° or 50°, are nearly 

straight, and end in the marginal teeth; nervation of lateral lobes similar, but secondaries 

more curved upward and camptodrome in the 

lower untoothed portion; finer nervation consisting of numerous strong nervilles, which are 

irregular and in places broken, and finer quadrangular areas. 

The above description is in the main drawn 

from the specimen shown in Plate XXXVI, 

figure 4, which is the best one available. It 

consists of a nearly perfect central lobe and a 

small portion of one lateral lobe, the two being 

separated hy ·a deep, narrow sinus. It is 

impossible to ascertain the size of this leaf 

when it was perfect, or to determine whether 

it had more than three lobes. It must have 

been 17 or 18 centimeters long and presumably 

20 centimeters or more broad between the tips 

of the lateral lobes. From its analogy with a 

species to which it is presumed to be related, 

it is thought probably to have been five-lobed, 

but this is not known. 

If I am correct in referring the other specimens here figured (Pl. XXXIX) to Aralia 

veatchii, the whole leaf was rriuch larger than 

the dimensions given above. Thus, the specimen shown in Plate XXXVIII, figure 1, could 

hardly have been less than 20 centimeters in 

length and 7 or 8 centimeters in greatest width. 

In Plate XXXIX there are portions of three 

leaves or, more properly, lobes, which, while 

not now in actual organic connection, are so 

placed as to lend support to the idea that this 

was a huge five-lobed .leaf. The central lobe, 

if it is such, was about 20 centimeters long and 

7 centimeters wide, and the other was about 16 

centimeters ·long and 6 centimeters wide. 

Both of these are more elliptical-lanceolate in 

shape than that shown in figure 1, and the 

margin is less sharply toothed. The fragment 

of a leaf given in Plate XXXVII, figure 4, is 

quite distinctly undulate-toothed. The nervation, however, is practi~ally the same in all the 

specimens figured under this name, and this is 

one of the strong reasons for considering them 

all as conspecific. 

There seems to be little or no doubt as to the 

propriety of referring these leaves to the genus 

Aralia on the basis of their resemblance to 

leaves from different horizons that have been 

so regarded. One of the species that is perhaps 

nearest to the present species, as exemplified in 

Plate XXXVI, figure 4, is Aralia saportanea 
A 'FOSSIL FLORA FROM THE FRONTIER FORMATION OF SOUTHWESTERN WYOMING. 93 

Lesquereux, 1 from the Dakota sandstone of 

Kansas. The Dakota species is a smaller form 

and has the lateral lobes at a much inore acute 

angle, the margins less conspicuously toothed, 

and the secondaries more curved upward, but 

they may well enough have belonged to the 

same genus. 

Occurrence: Frontier formation, north side 

of Little Muddy Creek, about 1 mile east of 

Cumberland, Wyo., in sec. 29, T. 19 N., R. 

116 W. Collected by A. C. Veatch in 1905. 

Family STAPHYLEACEAE 1 

Staphylea? fremonti Knowlton. n. sp. 

short-stalked, whereas in the fossil form the 

central leaflet has a markedly shorter stalk 

than the.,lateral ones. The margin in the living 

leaf is finely, sharply serrate, but in the fossil 

leaf it is entire. Again, the texture in S. 

fremonti was evidently much thicker than in 

S. trifolia. The shape, size, and nervation are 

approxin1ately the same in both forms. 

It wa,s at first thought possible that the 

leaves under consideration might be congeneric 

with Dewalquea tr·ifoliata Newberry, 2 from the 

Raritan formation of New Jersey, especially in 

view of a statement made by Berry 3 to the 

effect that "it is remarkable that where this 

Plate XXXII, figures 4, 5; Plate XXXIII, figure 5. genus has been found in abundance, two species 

Leaves trifoliolate, the leaflets petioled, all are usually described-one entire · and one with 

arising from the same point at the top of the 

main petiole; leaflets all of about the same size, 

elliptical-lanceolate, broadest near or just below 

the middle, whence they are gradually rounded 

or narrowed to the wedge-shaped base and to 

an acuminate apex; margin of leaflets perfectly 

entire; midrib exceedingly strong, straight; 

secondary nervation obscured by the thick 

substance of the leaflet; secondaries emerging 

at a low angle, close, nearly parallel, camptodrome, arching, and apparently joining well below the margin; finer nervation not discernible. 

toothed margins," the inference being that both 

forms probably grew on the same plant. This 

condition can not be true in the present instan-ce, for the leaves under discussion are 

clearly trifoliolate, while in Dewalquea the leaf 

is merely palmately decompound. 

One of the leaflets (Pl. XXXIII, fig. 5) shows 

a mine made in the leaf substance by an insect 

larva. (See p. 80.) 

Occurrence: Frontier formation, 1 mile east 

of Cumberland, Wyo. Collected by F. H. 

Knowlton and T. W. Stanton in 1908. 

Unknown systematic position. 

Phyllites :ficifolia Knowlton, n. sp. 

This beautiful species is represented by the 

two specimens figured, as well as their counterparts and a number of detached leaflets. They Plate XXXV, figure 3. have a thick general petiole of unknown length 

but at least 1 centimeter long. Standing on The leaf figured is all that was noted of this 

the top are the petioles of the leaflets, each of form. It was evidently a leaf some 15 or 18 

which is from 5 to 8 millimeters in length. centimeters in length and about 6 centimeters 

The petiole of the middle leaflet is uniformly a in width. It appears to have been ellipticallittle shorter than the lateral one. The leaf- lanceolate, very gradually narrowed at the 

lets are 3.5 to 4 centimeters long and about 12 base, and .Pr~s~ma.bl~ acuminate ~t the ape::. 

millimeters wide. The leaflets are very thick The margin IS Indistinct. There IS some eviin texture and, with the exception of the ex- dence ~o ~how that t~ere were a_fm: low teeth, 

tremely strong midrib, the secondary nerva- 1 b_ut this IS not certain. Th~ midrib ':as relation has been observed in only one or two leaf- tlvely strong. The secondaries, _of whiCh there 

lets. Here it is seen to be . thin close nearlv were probably about a dozen pairs, were alterparallel, and arching some dista~ce below th~ nate, at an angle of 35° or 40°, remote in the 

middle of the blade, somewhat curved upward, marg1n. 

. There is some uncertainty as to the propriety 

of this generic reference. These leaves appear 

to be close enough to the living Staphylea tr~folia 

Lesquereux to warrant their being considered 

as congeneric with it, though there are some 

differences. Thus, in the living form the lateral leaflets are sessile and the central one is 

1 Lesquereux, Leo, U.S. Geol. Survey Terr. Rept., vol. 8, p. 61, pl. 8, 

fig. 1, 1883. 

and presumably camptodrome. None of the 

finer nervation can be made out. 

This is probably a Ficus, but in the absence 

of definite knowledge concerning certain of the 

essential characters it seems best to leave its 

allocation to further and better material. 

2 Newberry, J. S., The flora of the Amboy clays: U. S. Geol. Survey 

Mon. 26, p. 129, pl. 22, figs. 4-i, 1895. 

a Berry, E. W., The Upper Cretaceous and Eocene floras of South 

Carolina and Georgia: U.S. Geol. Survey Prof. Paper 84, p. 42, 1914. 
94 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1917. 

Occurrence: Frontier formation, 1 mile east 

of Cumberland, Wyo. Collected by F. H. 

Knowlton and T. W. Stanton in 1908. · 

Phyllites dent~Ja Knowlton, n. sp. 

Plate XXXIV, :figure 8. 

The example figured is all that was found of 

this form. It is a segment apparently from 

the middle portion of a narrowly lanceolate 

leaf of membranaceous texture. It was acuminate at the apex, but the base is not known. 

The margin is provided with numerous low, 

sharp-pointed teeth. The nervation consists 

of a rather strong midrib and several pairs of 

·alternate thin secondaries which arise at a low 

angle and arch and join well inside the margin, 

sending branches from the outside to the marginal teeth. There are a few intermediate secondaries. The nervilles ar~ numerous, rather 

strong, and usually broken, forming irregular 

areas. 

This leaf, although a mere fragment, is so 

entirely distinct from any other focm found in 

these beds that it merits recognition. 

Occurrence: Frontier formation, 1 mile east 

of Cumberland, Wyo. Collected by F. H. 

Knowlton and T. W. Stanton in 1908. 

Phyllites sp. 

Plate XXXV, :figure 4b. 

The basal portion of the leaf here figured 

seems to represent a very distinct form that can 

probably be recognized if found in the future. 

It appears to have been ovate, the base at first 

abruptly rounded, then projected downward 

into a wedge-shaped portion. The rather 

slender, curved petiole is apparently complete. 

The margin is entire. The nervation consists 

of a rather slender midrib, a pair of very slender 

secondaries just above the basal margin of the 

blade, and a pair of opposite secondaries some 

distance above the base. These upper secondaries, or perhaps ((ribs," have branches on the 

outside that curve upward along. and perhaps 

end in the margin. These "ribs" do not join 

with the midrib where they come into contact 

with it but are distinct and run down along the 

midrib almost to the base of the leaf. The finer 

nervation can not be made out with certainty. 

Occurrence: Frontier formation, 1! miles 

south of Cumberland, Wyo., in the SE. 1 sec. 

6, T. 18 N., R. 116 W. From same horizon as 

plant beds 1 mile east of Cumberland. Colle"ted by T. W. Stanton September 1, 1913. 

FORMS EXCLUDED FROM THJS FLORA. 

· Genus TRICHOPTERIS. 

Trichopteris filamentosa Hall, in Fremont, op. cit., Appendix B, p. 306, pl. 2, :fig. 6, 1845. 

Trichopteris gracilis Hall, idem, p. _307, pl. 1, :fig. 5. 

This genus with two species was established 

by Hall, but clearly the forms are only rootlets 

of ferns. 

Phyllites .fremonti Unger. 

Phyllites jremonti Unger, Genera et species plantarum 

fossilium, p. 503, 1850. Leaf of a dicotyledonous 

plant (?) Hall, in Fremont, op. cit., Appendix B, 

p. 307, p. 2, :fig. 4, 1845. 

There is much doubt about the propriety of 

ineluding this species in the present flora. 

It waf:i placed by Hall at the ·end of the description of this flora, with the following 

remarks: 

Locality in the neighborhood of the specimens containing the preceding fossils and regarded by Capt. Fremont as belonging to the same formation. The rock containing them is a soft or very partially indurated clay, 

very unlike the hard and brittle mass containing the 

other· species. 

The probability that it did not come from 

the vicinity of the Cumberland locality is 

further strengthened by the chance statement 

"Fr.· Aug. 17, and No. 201' of collection," 

which appears to. mean that it was collected on 

Friday August 17, whereas the others are recorded ' under the date of August 19. F 1 re-~ 

mont's itinerary for the earlier date 1 indicates 

that on that day the expedition encamped on 

Blacks Fork of Green. River, some 40 miles 

east, of the locality reached on August 19. In 

the low hills bordering the stream he found 

((strata containing handsome and very distinct vecretable fossils." This locality is presulnably0 in the Green River formation, and if 

the above reasoning is correct, it apP,ears to 

dispose of the reference of this species to . the 

Colorado flora under consideration. The type 

specimen is now lost, and hence it is impossible 

to study the 1natrix in which it was preserved. 

This leaf was named and described by Unger 

as Phyllites fremonti,· from Hall's figu~e~ an_d 

Unger fell into the usual error of ascnb1ng 1t 

to Oregon, as the expedition went to "Oregon 

and north California." The above history has 

been given at some length for the purpose ~f 

settincr forth the unsatisfactory status of this 

specie~ and thus preventing future misunderstanding. 

1 Fremont, J. C., op. cit., p. 130. 
PLATES XXVIII-XXXIX. 

95 
PLATE XXVIII. 

FIGURES 1-4. Tapeinidium1 ' undulatum (Hall) Knowlton, n. comb. ________ __________________________ _ 

2a. Pinnules from figure 2, enlarged about three and one-half times to show nervation. __ . ___ _ 

96 

Page 

80 

80 
U. S. GEOLO(,liCAL SURVEY PROFESSIONAL PAPER 108 PLATE XXVIII 

1 

2a 

3 

4 

2 

FOSSIL FLORA FROM THE FRONTIER FORMATION. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 108 PLATE XXIX 

3 

4 

FOSSIL FLORA FROM THE FRONTIER FORMATION. 
PLATE XXIX. 

Page. 

FIGURES 1-4. Microtaenia variabilis Knowlton, n. sp .. _________________ . _____ . ___ . __ . ___ .. _ .............. _... 81 

4a. Uppermost pinnule in figure 4, enlarged three times to show nervation and sori. _. ___ . _____ ____ . 81 

~7 
PLATE XXX. 

Page. 

FIGURES 1, 2. Microtaenia paucifolia (Hall) Knowlton, n. comb.............................................. 82 

3, 4. Dryopteris coloradensis Knowlton, n. sp ......... _... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 

5. Dennstaedtia? fremonti (Hall) Knowlton, n. comb .................................. -........... 83 

98 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 108 PLATE XXX 

3 

FOSSIL FLORA FROM THE FRONTIER FORMATION. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 108 PLATE XXXI 

2 

5 

FOSSIL FLORA FROM THE FRONTIER FORMATION. 
PLATE XXXI. 

Page. 

FIGUR E l. Dennstaedtia? fremonti Knowlton, n. sp ..... . ................. .. .............. . . . ..... . ... . . _... . 83 

2-5. Asplenium occidentale Knowlton, n. sp... . ...... ... ................. . ........................... 84 

6. Anemia (remonti Knowlton, n. sp ................ .....•••................ ~....... ......... ..... 84 

99 
PLATE XXXII. 

Page. 

FIGURES 1-3. Anemia fremonti Knowlton, n. sp. _______ __ ____ ___ __________ _______________________ . _......... 84 

4, 5. Staphylea f fremonti Knowlton, n. sp .............. ___ . ___ .... _ ............... __ . . . _ . _ . . . . . . . 93 

100 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 108 PLATE XXXII 

4 

1 

FOSSIL FLORA FROM THE FRONTIER FORMATION. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 108 PLATE XXXIII 

1 

3 

4 

6 

5 

FOSSIL FLORA FROM THE FRONTIER FORMATION. 
PLATE XXXIII. 

Page. 

FIGURE 1. Smilax? coloradensis Knowlton, n. sp. ______ . ___ . _. _____________ ........ _______ . _______ .......... 85 

2-4. Quercus stantoni Knowlton, n. sp. ____ . ___ .. _ .. _______________ __ __ ... _____ . __ . _. ______ .. . ....... 86 

5. Leaflet of Staphylea? fremonti, showing mine of microlepidopterous larva. ____ .... __ . . . . . . . . . . . . . . 93 

6. Equisetum sp ................................•.•.•..••.•.•.•...•................. ____ ......... 85 

101 
PLATE XXXIV. 

Page. 

FIGURE 1. Myrica nervosa Knowlton, n. sp. ____________ ~ ______________________________ . __ .. __ ...... _ . . . . . . . 85 

2, 3. F'ieusf sp ___ . _ ..... _. _. _. _. _. _. ___ . ____ . ____ . _. _. _. _. ___ . _________________________ . ___ . ____ .. 88 

4-6. F'icus (remonti Knowlton, n. sp _ ... _ . _ . _____ . ___ . _ . _______ . __________________________________ . . 87 

7. Dryandroides lanceolata Knowlton, n. s:;:> _____________ . _ . ____________________________________ __ _ . 89 

8. Phyllites dentata -Knowlton, n. sp . _. _. ___ .. __ . _ ... _. _______ . __ . ___ . _. ___ ... ___ . __ .. ___ . ___ .. _.. 94 

102 
U. S. GEOLOGICAL SURVEY PROFESS!ONAL PAPER 108 PLATE XXXIV 

6 

7 8 

5 

FOSSIL FLORA FROM THE FRONTIER FORMATION. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 108 PLATE XXXV 

1 2 

4 

3 

FOSSIL FLORA FROM THE FRONTIER FORMATION. 
PLATE XXXV. 

Page. 

FIGURE 1. FU:u~J'! sp ................................ _ . _ . _ ... . . . . __ . _ ... __ ... _ . _ ... . ..... _ ... _ . . . . . . . . . . . . . 88 

2. Cinnamomum? sp ........................ _ . _ . _ . _ .. __ . _ . . . . ___ . _ . . . . . . . . . . . . . . . . . 89 

3. Phyllites fidfolia Knowlton, n. sp . .............. __ . _ _ . . . . . . . . . . . . . . . . . . . . . . . . 93 

4a. Salix jrontierensis Knowlton, n. sp .............. _ .. _ . . _ _ . . . . . . . . . . . . . . . . . . . . . . . . 86 

{b. Phyllites sp ........................ . ... . . . . _ . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . . 94 

4c. Ficus jremonti Knowlton, n. sp ............ _ ... _ . _ . _ ... _ .... ............ ........ : . . . . . . . . . . . . . . . . 87 

5. Leaf of FU:us.fremonti Knowlton, twice natural size, to show egg mass of microlepidopterous insect.. 87 

103 
PLATE XXXVI. 

Page. 

FIGURES 1-3. Dewalquea pulchella Knowlton, n. sp ....... . ....... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 

4. Aralia veatchii Knowlton, n. sp........ . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 

104 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 108 PLATE XXXVI 

FOSSIL FLORA FROM THE FRONTIER FORMATION. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 108 PLATE XXXVII 

1 

FOSSIL FLORA FROM THE FRONTIER FORMATION. 
PLATE XXXVII. 

Page. 

FIGURES 1-3. Dewalquea pulchella Knowlton, n. sp ........... _. __ ... _.. ........................... .. . . . . . 90 

4. Aralia veatchii Knowlton, n. sp.. . . . . . .. . . . .. . . .. .. .. .. .. . . .. . . .. . • . .. • . . . . .. .. . . . . . . .. . . .. 92 

105 
PLATE XXXVIII. 

Page. 

FIGURE 1. Aralia veatchii Knowlton, n. sp............................................................... 93 

2. Cinnamomum hesperium Knowlton, n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 

3. Salix cumberlandensis Knowlton, n. sp......................................................... 86 

106 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 108 PLATE XXXVIII 

2 

1 3 

FOSSIL FLORA FROM THE FRONTIER FORMATION. 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 108 PLATE XXXIX 

FOSSIL FLORA FROM THE FRONTIER FORMATION. 
PLATE XXXIX. 

Page. 

Aralia veatchi,i Knowlton, n. sp ...... __ .. _ .. ____ ......... _ .. _____ ..................................... 92 

107 

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