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UNITED STATES DEPARTMENT OF THE INTERIOR 

Harold L. Ickes, Secretary 

GEOLOGICAL SURVEY 

W. C. Mendenhall, Director 

Professional Paper 185-D 

A FLORA OF POTTSVILLE AGE 

FROM THE MOSQUITO RANGE, COLORADO 

BY 

CHARLES B. READ 

Shorter contributions to general geology, 1934-35 

(Pages 79-96) 

UNITED STATES 

GOVERNMENT PRINTING OFFICE 

WASHINGTON : 1934 

For sale by the Superintendent of Documents, Washington, D . C. - - - - - - Price 10 cents 
CONTENTS. 

Page 

Abstract_____________________________________________________________________________________________________ 79 

Introduction __________________________________________________ _ ·---------------------------------------------- 79 

Geologic relations of the flora ____________________ .. __________________________________________ .. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 79 

Com position of the flora _____ .. ___________________________________________ :. _____ .. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 81 

Systematic descriptions _____________ . ___________________ __________ .. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 82 

ILLUSTRATIONS 

Page 

PLATES 16-18. Plants of Pottsville age from the Mosquito Range, Colo_____________________________________________ 93 

FIGURE 3. Sections of lower part of the Weber(?) formation at Evans Peak and Pennsylvania Mountain, Colo___________ 80 

II 
A FLORA. OF POTTSVILLE AGE FROM THE MOSQUITO RANGE, COLORADO 

By CHARLES B .. READ 

ABSTRACT 

Seventeen species of fossil plants from the lower part of 

the Weber ( ?) forma tion of the Mosquito Range, Colo., show 

that the age of the containing beds is lower Pennsylvanian and 

indicate a correlation with the Pottsville formation of the 

eastern United States. Although predominantly a typical Carboniferous flora, certain of the species are unique. L epido'-

strobus weberensis, n. sp., Adi an tites rock'Jt'fYI;ontanus, n. sp., and 

Da.otylophyllum johnsoni , n. gen. and sp., are proposed. Other 

forms recognized include Stigmaria verrucosa, Calamites sp., 

Asterophyllites longifoliu8'1, Neuropteris dluhoschi, N. het erophylla, N. gif}antea?, Spheoopteris asplen'Loides, S. cf. S. 

microcarpa, S. cheathami, Diplotniema pa.tenti sS'ima, Cordaites 

sp., Oordaianthus sp., Oo1·daicar pon sp., and Trichopitys whitei. 

INTRODUCTION 

This paper describes a small fossil flora from the 

vicinity of Leadville, central Colorado. · The beds 

from which the flora was collected have long been 

referred to as the "vVeber formation", though with 

considerable doubt on the part of many geologists 

that all the beds so named in Colorado are correlative 

with the Weber quartzite of northeastern Utah. In 

current usage these Colorado beds are designated the 

"Weber ( ~) formatl.on." ' 

The remains of plants from the upper Paleozoic. 

sections of Colorado have received very little attention. A few small collections of Permian plants have 

been made at several stations, and a florule from the 

Glen Eyrie shale member of the Fountain formation 

has been identified by White.1 Small lots of very 

fragmentary material have been collected from other 

localities by several individuals, but these have generally been of negligible value. 

The plants which are dealt with here were discovered by J. H. Johnson and C. D. Hier, of the Colorado School of · Mines, during the summer of 1930, 

while engaged in a stratigraphic study of the Pennsylvanian sedimentary rocks in the Mosquito Range. 

In September of the same year the writer visited the 

localities in company with Messrs. Johnson and Hier 

and added a quantity of material to the collections 

pre.viously made. These localities are almost due 

east of Leadville, on the flanks of Evans Peak and 

Pennsylvania Mountain. Their more specific location 

is given on another page. 

1 Finlay, G. I., U.S. Geol. Survey Geol. Atlas, Colorado Springs folio 

(no. 203), p. 7, 1916. 

Much advice and constructive criticism have been 

given during the course of the study by Mr. David 

White, to whom grateful acknowledgments are due. 

GEOLOGIC RELATIONS OF THE FLORA 

Two localities on Evans Peak and Pennsylvania 

Mountain furnish the plant material described here. 

In this area the Weber ( ~) formation lies above the 

Leadville: limestone with apparent conformity. Its 

general features have been summed up by several 

geologists in reports on the Leadville mining district 2 and on the stratigraphy of the Pennsylvanian 

formations of Colorado.3 It is sufficient to say here 

that the formation comprises a lower thin shaly division and a n1uch thicker upper sandy and conglomeratic division, the two aggregating 1,000 feet in the 

Leadville district but thickening to 2,800 feet in 

adjacent regions. These are often spoken of as the 

t" Weber shales " and t" Weber grits." 4 Thin beds 

of limestone containing invertebrates occur at several 

horizons. Both the shales and the sandstones are 

highly micaceous. 

Johnson has published sections which give in detail 

the lithology of the formation. 5 These sections definitely establish the position of the plant horizons in 

the lower part of the formation and show their relations to the enclosing strata, some of which may be 

identified at other localities, as well as indicating 

,their position with reference to invertebrate faunas. 

The relations of the sections . at Evans Peak and 

Pennsylvania. Mountain are diagrammatically shown 

in figure 3, which has also been prepared by Mr. 

Johnson. It will be seen tliat the plant-bearing beds 

(bed 17 (locality 8049), Evans Peak; bed 5 (locality 

8050), Pennsylvania Mountain) are at very nearly the 

same position in the two sectio~s. Their exact equiva2 Emmons, S. F., Geology and mining industry of Leadville, Co:io. : 

U.S. Geol. Survey Mon. 12, p. 69, 1886. Emmons, S. F., Irving, J . D., 

and Loughlin, G. F ., Geology and ore deposits of the Leadville mining 

district, Colo. : U.S. Geol. Survey Prof. Paper 148, pp. 38-39, 1927. 3 Girty, G. H., The Carboniferous formations and faunas of Colorado: 

U.S. Geol. Survey Prof. Paper 16, pp. 242-243, 258 et seq., 1903. Johnson, J. H., Paleozoic formations of the Mosquito Range, Colo.: U.S. 

Geoi. Survey Prof. Paper 185-B, 1934. 4 A dagger (t) preceding a geologic name indicates that the name 

has been abandoned or rejected for use in classification in publicatio]ls 

of the U.S. Geological Survey. Quotation marks, formerly used to indicate abandoned or rejected names, are now used only in the ordinary 

sense. 6 J,ohnson, J . H., op. cit., pp. 33'-42. 

79 
80 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 19 3 4-3 5 

Bed 

50 

EVANS 

PEAK 

13~~~~~· \\ 

\ 

\ 

' \ 

\ 

\ 

\ 

\ 

\ 

\ 

200±feet 

2 

Vertical scale 

50 0 50 

\ 

\ 

\ 

' \ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

100 Feet 

\ 

\ 

PENNSYLVANIA 

MOUNTAIN 

30 

14 

FIGURE 3;-Sections of lower part of the Webrr ( ?) formation at Evans Park and Pennsylvania Mountain, Colo. 
A FLORA OF POTTSVILLE AGE FROM THE MOSQUITO RANGE, COLORADO 81 

lence is not yet established, but the geologic and stratigraphic relations suggest that there cannot be more 

than 100 feet of difference. The floral evidence is in 

complete accord with this. 

A large fauna has been listed from the Weber ( 1) 

:formation in the area around Leadville. The study ' 

of this fauna caused Girty 6 to conclude that "the 

Weber and lower Maroon formations and the Weber 

shales and Weber grits come very early in Pennsylvanian time and are probably older than any beds of 

the Kansas and Nebraska sections." More recent work 

has shown that the Maroon is of Permian age, but 

the opinion regarding the age of the Weber ( 1) has 

been generally accepted. · 

The collections of fossil plants from the lower part 

of the Weber ( 1) corroborate the evidence of the 

fauna in pointing out the early Pennsylvanian age of 

at least this part of the formation. Some of the species are identical with or closely related to common 

and characteristic species of the Pottsville of the 

Appalachian region. These are as follows: 

Sphenopteris asplenioides Sternberg 

Sphenopteris cf. S. microcarpa Lesquereux 

Sphenopteris cheathami (Lesquereux) Read, n. comb. 

Diplotomema patentissima (Ettingshausen) Stur. 

Neuropteris gigantea Sternberg? 

Neuropteris heterophylla Brongniart 

Neuropteris dluhoschi Stur. 

Stigmaria verrucosa (Martin) S. A. Miller 

Oardiocarpon sp. 

In addition, there are several specifically unidentifiable forms and several new forms which do not give 

any unusual aspect to the flora. It is notable that 

this aggregate of species is comparable to floras of 

the middle Pottsville. The evidence is much too 

weak, however, to allow any definite statement of 

such a refined correlation. 

Three of the species that are represented in the 

Evans Peak collection are unique. These are Trichopitys whitei, Dactylophyllwm johmsoni, and Adiantites rockymontanus. The first two in particular are 

unusual forms belonging to genera previously unknown in America and having a very puzzling discontinuous stratigraphic and areal distribution in 

Europe. Although the genus Adi(Jfntites is by no 

means uncommon in early Pennsylvanian strata, 

Adiantites rockymontan11i8 is suggestive of pre-Pottsville forms and shows peculiarities that makes it very 

distinct. · 

The lower Weber ( 1) flora has been compared~ 

with indifferent success, with several lots of plants 

from formations that are regarded as essentially the 

equivalent of the Weber ( 1). The black shales of 

the Glen Eyrie member of the Fountain formation 

6 Girty, G. H., op. cit., p. 264. 

have been correlated with the lower Weber ( 1) or 

t Weber shales and should contain floral evidence to 

justify this correlation. A flora from these beds 

has been studied by David vVhite, and a report is 

included in the Colorado Springs folio. 7 Recent 

collections have amplified the number of species. 

Only three, Stigma·ria verrwcos(J), Sphenopteris (J)Splenioides, and a very doubtfully identified Adiantites 

J'ockymontanus, are present in ·the Weber ( ~) flora. 

1Vhite inclined to the opinion that the Glen Eyrie 

flora is of upper Pottsville age. There can be no 

loubt that it has a younger appearance than the 

"\Veber ( 1) flora. The other collections that have 

been studied are too fragmentary to allow any careful comparison. 

This evidence may be summed up by saying that the 

lower portion of the Weber ( 1) formation bears a flora 

which is indubitably Pottsville. Certain of the 

species indicate a. reference to the middle Pottsville, 

hut these are insufficient to permit a dogmatic statement to that effect. The flora of the Glen Eyrie member of the Fountain formation is tentatively regarded as somewhat younger than the Weber( 1) 

flora, although also of Pottsville age. 

COMPOSITION OF THE FLORA 

A systematic list of the species recognized 1n the 

Evans Peak flora is given below. 

Pteridophyta : 

Lycopodiales : 

Lepidodendraceae : 

Lepidostrobus weberensis. 

Stigmaria verrucosa. 

Equisetales : 

Calamariaceae : 

Ca lamites sp. 

Asterophyllite·s longifolius? 

Spermatophyta: 

Gymnospermae: 

Cycado:fi.licales : 

Neuropterideae: 

N europteris dl-uhoschi. 

Neuropteris heterophylla. 

Neuropter\s gigantea? 

Sphenopterideae : 

Sphenopteris asplenioides. 

Sphenopteris cf. S. microcarpa. 

Sphenopteris cheathami. 

Diplotmema patentissima. 

Adiantites rockymontanus. 

CordaitaleS': 

Cordaites sp. 

Cordaianthus sp. 

Cordaicarpon sp. 

Position uncertain : 

Palaeophyllales: 

Trichopitys whitei. 

Dactylophyllum jcihnsoni. 

7 Finlay, G. I., U.S. Geol. Survey Geol. Atlas, Coloradc Springs folio 

(no. 203), p. 7, 1916. 
82 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1934-35 

The flora, it will be seen, contains 17 species of fossil 

plants, 15 of which are characteristic of the American Carboniferous and 2 are unique. The present 

status of the flora is, however, very incomplete, and 

the number of species will probably be greatly increased wh~n further studies. are made. 

SYSTEMATIC DESCRIPTIONS 

PTERIDOPHYTA 

LYCOPODIALES 

LEPIDODENDRACEAE 

Lepidostrobus weberensis Read, n. sp. 

Plate 16, figures 1, 2, 4 

Strobilus linear, 34 to over 7 4 millimeters in length, 

broadest at base and tapering gradually upward to 

an acutely rounded apex; axis about 1 millimeter in 

width, with very narrowly fusiform sporophyll 

eushions less than 0.25 millimeter broad and from 1 

to 2 millimeters long, the vascular and parichni scars 

unobservable. Sporophylls crowded, about 1 millimeter distant, spirally arranged, at right or slightly 

acute angles to axis and becoming more acute apically, 

the keel 5 to 8 millimeters long, narrow, thin, the 

sporangia seated on the adaxial surface, 4 to 7 millimeters long, low, the crest line nearly straight or 

slightly convex, rounded distally, apparently attached 

by whole of base; blade arching rapidly from point 

of inflection to form a narrowly obtuse or nearly right 

a.ngle to keel, overlapping next four or five more distal sporophylls, thin, narrow, ·probably acuminatelanceolate, midrib not observable. The whole cone 

has a very compact aspect. 

Microspores occasionally observed in distal sporangia; megaspores not observed. 

Owing to the abundance of these strobili at locality 8050 it has been deemed best to describe them as 

new in spite of their poor preservation. Figure 1 · 

~hows one of the better strobili and permits the essential features to be made out. The extremely slender 

form of the cone is typical,. as is the compactness. 

The axis is very small and bears elongate sporophyll 

cushions. The keels depart at very nearly right angles to the axis; the blades are flexed strongly upward 

and are imbricate. In figure 4 a similar · strobilus is 

illustrated. 

Figure 2 gives some idea of the external aspect of 

the strobilus and demonstrates somewhat the overlapping of the blades. . 

Comparable forms are few. Lepidostrobus linearis 

Goeppert 8 and L. attenuatus Goeppert 9 furnish some 

points of similarity insofar as general shape is con8 Goeppert, H. R., Die f·ossile Flora der permischen Formation: 

Palaeontographica, vol. 12, pp. 140-141, pl. 19, figs. 1-7, 1864. 9 Idem, pp. 141-142, pl. 19, figs. 8-13; pl. 52, figs. 4, ·7, 1864. 

cerned, but both have larger and heavier axes, keels, 

and blades. In the Lacoe c~llection of fossil plants 

in the United States National Museum there is a 

specimen (no. 16042; 305 A) labeled "Lepidostrobus 

variabilis Lindley and Hutton" which is extremely 

slender for its size and which may be wrongly identified. With it L. weberensis compares in many respects 

. but is much smaller and fails to show the heavy axis 

that is present in the Lacoe plant. 

No suggestion can be made concerning the characteristics of the plant that bore the strobili other 

than that it was a lepidophyte. These cones and 

Stigmaria verrucosa comprise the whole of the remains of such plants which have so far been collected 

from the localities. 

Lepidostrobus U'eberen.sis is so unusual a form and 

its affinities are so vague that it furnishes nothing of 

value concerning the age of the deposits. The species 

1 name, WJeberensis, refers to the formation from which 

it was obtained, the Weber (?). 

Occurrence : Bed 17 of Evans Peak section ; collected by 

J. H. Johnson, 0. D. Hier, and 0. B. Read. 

Stigmaria verrucosa (Martin) S. A. Miller 

Plate 16, figure 5, c 

Phytolithus verrucosus Martin, Outlines of an attempt to 

establish a knowledge of extraneous fossils on scientific 

principles, p. 203, 1809 ; Petrificata derbiensis, p. 23, pls. 

11-13, 1809. 

Steinhauer, Am. Philos. Soc. Trans., voi. 1, p. 268, pl. 4 

figs. 1-4, 1818. 

Va.,1'iolarri a ficoifles Sternberg, Flora der Vorwelt, vol. 1, fasc. 

1, p. 24, pl. 40, figs. 1-3, 1820. 

Stigmaria ficoides (Sternberg) Bromgniart, Mus. hist. nat. 

Mem:, vol. 8, pp. 228, 239, p. 1, fig. 7, 1822. 

Stigmaria verruoosa S. A. Miller, American Paleozoic fossils, 

p. 40, 1877. . 

White, U.S. Geol. Survey Mon. 37, pp. 244-245, 1899. 

In the Evans Peak and Pennsylvania Mountain collections there are a number of specimens of shale bearing fragments of .Stignwria verr1JJCO$a. These are too 

well known to necessitate any description and are important only in indicating the presence of lepidophytes 

in the flora. 

The specific name v-errvucosa instead of ficoides has 

been used because of the fact that Martin's name, 

which seems to be a good binomial, has a priority of 

several years over Sternberg's, although this fact is 

not generally observed. David White, however, has 

discussed this problem of nomenclature at considerable 

length and has adopted the name used here. It is 

therefore not necessary to go into the matter and is 

sufficient to state that White's opinion appears to be 

correct. 

Occurrence : Bed 17 of Evans Peak section; bed 5 of Pennsylvania Mountain section; collected by J. H. Johnson, 0. D. 

Hier, and 0. B. Read. 
A FLORA OF POTTSVILL~ AGE FROM THE MOSQUITO RANGE, COLORADO 83 

EQUISE·TALES 

CALA:MARIACEAE 

Calamites sp. 

There are several fragments of 0 ala1nites in the 

collections, but their preservation is· so poor that it is 

impossible to identify them specifically. They are of 

the coarse, alternating-ribbed type, and it is possible 

that more than one species is represented. Their im-, 

portance is· slight, as they only bear out the material 

]nference to be drawn from the Asterophyllites foliage 

that arborescent calamarians were present in the original flora. 

Occurrence : Bed 17 of Evans Peak section ; collected by 

J. H. Johnson, C. D. Hier, and C. B. Read. 

Asterophyllites lon~ifolius (Sternberg) Brongniart? 

Plate . 16, figure 8 

Two specimens .from locality 8049 represent a 

species of Asterophyllites very closely related to if not 

identical . with Asterophyllites longif oliUJS (Sternberg) 

Brongniart.10 In view of the· insufficient and very 

fragmentary material, the name is used in this paper 

with a query. 

The figure shows the general aspect of the best 

specimen, which is an incomplete whorl of leaves. 

The laminae are apparently rigid, and the under surface is finely longitudinally striate. In another specimen the leaves attain a length of 25 millimeters . . A 

scarcely perceptible sheath unites the leaves at the 

base. 

Asterophyllites longzfoliUJS (Sternberg) Brongniart 

has been completely discussed by White,11 and it is 

not necessary to dwell in detail upon this subject in 

the pr.esent paper. 

In Europe Asterophyllite:s longifolilus is a longranging form, being recorded fr<?m Westphalian to 

Permian. In North America it has previous!~ been 

reported only in post-Pottsville strata. The Weber 

( ? ) plant beds are beyond any doubt Pottsville. This 

apare.nt discrepauey in range may be due to the 

·present insufficient knowledge of American Carboniferous floras or to an erroneous identification based on 

the fragmentary material. 

Occurrence : Bed 17 of Eva:vs Peak section ; collected by 

J. H. Johnson, C. D. Hier, and C. B. Read. 

10 Sternberg, G. K., Flora der Vorwelt, vol. 1, p. 29, pl. 58, :fig. 1, 

1820. Brongniart, Adolphe, Prodrome·, p. 157 (159), 1828. 11 White, David, Fossil :flora of the lower Coal Measures of Missouri: 

U.S. Geol. Survey Mon. 37, pp. 153-156, 1899. 

SPERMATOPHYTA 

GY:MNOSPERMAE . 

CYCADOFILICALES 

NEUROPTERIDEAE 

N europteris dluhoschi Stur 

Plate 17, figure 5 

Neuropteris llluhoschi Stur, K.-k. geol. Reichsanstalt Abh., 

vol. 8, no. 2, p. 183 ( 289), pl. 11, fig. 9, 1877. 

White, Geol. Soc. America Bull., vol. 4, p. 128, 1893. 

Frond large, at least tripinnate. Penultimate pin;-

nae flexuose., broadly lanceolate, the axis strong, longitudinally multistriate; ultimate pinnae borne alternately, linear-lanceolate with ac~te apices, the rachis 

small, striate similar to penultimate rachis; pinnules 

crowded, touching or slightly imbricate, at right 

angles to the axis or a little oblique with decurrent 

base, a little inflated, flexuose, lanceolate with acute, 

pointed, or narrowly rounded apices; hroadest point 

below middle, base equilateral and cordate or more 

bften inequilateral and attenuate below, midrib strong, 

marked by groove, extending nearly to apex before 

breaking up into numerous secondaries; secondary 

veins numerous, crowded, decurrent, arching rapidly 

to follow a nearly right angle course to margin, sometimes even arched backward, dichotomizing once or 

twice. 

Newrop-teris dluhoschi Stur is one of the transitional neuraiethopterids which are so abundant in the 

Pottsville of this country. The figure shows a fragment of a penultimate pinna bearing two ultimate 

pinnae. It will be noted that the axis is large and 

longitudinally striate, although this last feature is 

not ·shown in the illustration. The alethopteridlike 

appearance of the pinnules is striking, but the mode 

of attachment by the midrib and directly adjacent 

tissue rather than by the whole breadth of the base 

definitely places the plant in N europtevris. The somewhat linear, straplike pinnules haye been slightly 

rolled at the margins, the shape being in reaHty more 

inflated. The midrib is deeply set, in a heavy furrow 

and is strong to a point within a short distance of the 

apex. The ·secondary nervation is similar in many 

respects to that of Alethopteris, consisting of crowded, 

decurrent veins rapidly arching to a right-angle position and dichotomizing infrequently. 

N europteris dbu:hosclui is comparable ·in external 

morphology with several species that are characteristic of the Pottsville formation and its equivalents in 

North America and in Europe. It . is readily con-
84 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1934-35 

fused with N ewropteris schlehami Stur,12 as is attested by an examination of the figures and descriptions given by numerous European investigators. 

N europteris elrodi Lesquereux, which is possibly indistinguishable from N. schlehani, is perhaps the most 

closely related American species but can be distinguished by the broader pinnules with more rounded, 

obtuse · apices and the shallower sinus marking the 

midrib. N europteris sm.ithsii Lesquereux likewise 

exhibits many points of similarity with N. dlwhoschi 

but in general is characterized by its shorter, more 

compact, quadrate pinnules with fine, arching veins. 

N europteris pocahontas White 13 and its varieties resemble N europteris dluhosclui but are readily separated by the form ·of the pinnules and by the open and 

fl.exuose venation. .White has suggested that this 

species should be segregated into N eurro-callipteris 

rather than N euro-alethopteris. 

N europteris dliuhoschi furnishes very reliable information concerning the age of the flora. It is typical 

of a subgenus which reached its maximum development in Pottsville time and which persisted into the 

Allegheny with only a few highly specialized repre~ 

sentatives. The species mentioned above, which are 

almost certainly closely related to N. dl'/!;hosahi, are 

all of Pottsville age. In Europe this species has been 

noted in the Westphalian. The presence of N. dlwhoschi Stur in the Weber (?) flora is therefore indicative 

of · the Pottsville age of the basal portion of the 

formation. 

N europteris heterophylla Brongniart 1 

Plate 16, figure 7 

Lithosmunda minor Scheuchzer, Herbarium diluvianum, p. 

15, pl. 4, fig. 3, 1709. 

Liud, Lithophylacii Britannici Iconographia, p. 12, pl. 4, 

fig. 189, 1760. 

Phytolithus ( Osmumdae regalis) Martin, Petrificata derbiensis, 

pl. 19, figs. 1-3, 1809. 

F'ilicites (N ewropteris) heterophyllus Brongniart, Classification des vegetaux fossiles, p. 33, pl. 2, figs. 6a, 6b, 1822. 

N europter-is heterophylla Brongniart, Prodrome, p. 53, 1828 ; 

Historie des v~getaux fossiles, vol. 1, p. 243, pl. 71; 

pl. 72, fig. 2, 1829. 

Several fragmentary specimens in the collections 

indicate beyond reasonable doubt that one of the 

vVeber (?) elements is N europteriK heterophylla as 

defined and figured by Brongniart. The Colorado 

material has been carefully compared with numerous 

authentic specimens .from France and England which 

are in the Lacoe collection, with the re.sult that no 

trustworthy difference of specific magnitude has been 

12 Stur, D., Die . Culm-Flora: K.-k. geol. Reichsanstalt Abh., Band 8, 

Heft 2, p. 183 (289), pl. 11, fig. 9, 1877. 13 White, David, The stratigraphic succession of the. fossil floras of 

the Pottsville formation in the southern anthracite coal field, Pa. : 

U.S. Geol. Survey 20th Ann. Rept., pt. 2, pp. 888-893, pl. 188, figs. 2-5; 

pl. 189, figs. 4, 4a, 5, 5a, 5b; pl. 190, fig. 7; pl. 191, figs. 1-5, 1900. 

S:ound. The lanceolate, acutely pointed pinnae and 

the flexuose pinnules becoming odontopteroid apically 

agree very well in the Westphalian and Evans Peak 

material. 

The historical study of N europteris heterophylla 

Brongniart has indicated that there has been much 

confusion in the concepts of this and related forms. 

Several species have been de.scri bed which are undoubtedly identical with N. heterophylla as it was 

understood by Brongniart. Likewise ther.e are forms 

included in N. heterophylla which are certainly distinct. In the writer's opinion there is no question as 

to the validity of the species, however, despite statements to the contrary.u 

In America a certain amount of confusion ha.s resulted from Lesquereux's identification of N eu.ropteris 

O'Vata Hoffman as N ewropteris loschii Brongniart. It 

is generally admitted that 1.V. losohii and N. heterophylla are identical, although N. ovata is quite distinct. As a result of this misidentification N. heterophylla has been reported in America as ranging up 

almo;St to the Permian, though as a matter of fact 

its occurrence is ~ery rare and is restricted to strata 

of Pottsville age. N. heterophylla is definitely related to N. rarinervis, N. tenuifoli(JJ, N. flex+wosa, and 

an undescribed species, N. tennesseefJ'fna Lesquereux 

MS., 1 but can be separated, although this is accompli.shed only with difficulty in some cases. 

· Occurrence : Bed 17 of Evans Peak section ; collected by 

J. H. Johnson, C. D. Hier, and C. B. Read. 

Neuropteris gigantea Sternberg? 

Under this name a few fragments that are not suffieiently well preserved to allow certain identification 

are here recorded. The pinnules are large, apparently 

broad-lanceolate 'vith subparallel margins in th~ basal 

portion, and are truncate-cordate at the base. The 

nervation, though so indistinct that it is impossible 

to make out all the details, is more acute with reference to the poorly defined midrib than in the specimens figured by Sternberg 1. 5 or in specimens labeled 

"N europteris subfaloata" by Lesquereux 16 and more 

recently identified with N. gigante(JJ Sternberg by -

White.17 According to White the typical form of 

LV. giqantea occurs only in the upper beds of the Pottsville group of the Appalachian region. There are 

forerunners, though, which extend well back toward 

the n1iddle Pottsville, the lifi?.it of their range being 

14 Bolton, Edith, A critical study of ·certain species of the genus 

Neuropteris Brongniart: Linnean Soc. London Jour., Botany, vol. 47, p. 

310, 1926. 

• 15 Sternberg, G. K., Fl•ora der Vorwelt, vol. 1, p. 27, pl. 22, 1825 

(Osmunda). 

16 Lesquereux, Leo, Description of the coal flora : 2d Pennsylvania 

Geol. Survey Rept. P, vol. 1, p. 102; atlas, pl. 13, figs. 5, 6, 1880. 

17 White, David, The stratigraphic succession of the fossil floras of 

the Pottsville fo rmation in the s•outhern anthracite coal field, Pa. : U.S. 

Geol. Survey 20th Ann. Rept., pt. 2, p. 895, 1900. 
A FLOltA OF POTTSVILLE AGE FROM THE MOSQUITO RANGE, COLORADO 85 

nnknown to the writer. Thus it is apparent that this 

species can afford little exact information as to the 

age of the beds, . although it · confirms the rough 

identification of the flora as Pottsville. 

Occurrence: Bed 17, Evans Peak section; collected by J. H. 

Johnson, C. D. Hier, and C. B. Read. 

Family SPHENOPTERIDEAE 

Sphenopteris cf. S. microcarpa Lesquereux 

Plate 17, figures 6, 7 

Frond polypinnate. Penultimate pinnae linearlanceolate ( n' the rachides sinuose, strong, irregularly 

rugose. Ultimate pinnae distant, alternate, attached 

to penultimate rachis at peaks of outward-bulging 

flexes at open angles, short, lanceolate, . the axes 

weak, broadly winged. Pinnules opposite or subopposite, distant, attached by a very short· stalk 

varying from narrow and distinct to wide and indistinct, ovate, decurrent, varying in size and shape according to position on rachis; lower pinnules two or 

chiefly three, lobed distally, these separated by sinuses 

extending about halfway to base, directed outward 

and slightly forward, acutely rounded apically; occasionally inferior basal pinnule entire and reniform; 

distal pinnules more nearly linear, entire or often bi-

+obed, the stalks scarcely distinguishable; terminal 

pinnule small, bilobed or trilobed, these slightly swollen. Laminae formed of apparently tough coriaceous tissue. Nervation poorly preserved, the midrib 

decurrent, giving off laterals to supply each lobe, these 

<continuing to distal margin. 

The single fragment of this species fails to show 

any details which conclusively establish its taxonorn,ic 

position. Figure 7 reproduces the specimen. The 

most conspicuous feature is the angularly sinuose rachis. This is rather thick and appears to have been 

very woody. It is rugose but without any very definite 

pattern. The ultimate pinnae are distant and appear 

to have been rigid. 

In figure 6 the same specimen is shown enlarged 

three times. The pinnule outline is ovate or broadly 

cuneate but is modified by the presence of lobes in 

the apical portion of the lamina. Although the pinnules are generally distant, they tend to become 

crowded apically. They are seated by Yery short 

stalks of varying width on the alate rachis. 

This plant resembles, Sphenopteris microcarpa Lesquereux 18 in numerous respects but fails to show the 

prominent denticulate pinnule margins which characterize that species. The pinnules of S. miarocarp'a 

are usually of different proportions, being comn1only 

longer and narrower. Although it is possible that 

18 Lesquereux, Leo, op. cit., pp. 280-281, pl. 47, figs. 2-2b. 

59021-34--2 

the range of variation in S. microcarpa Lesquereux 

includes the present specimen, the identification given 

here is only provisional. 

The trilobate pinnules suggest Sphenopteris aspleJ/.ioides Sternberg in certain of its dissected variants, 

but the proportions are different. There is no indie:ation of the thick lamina which characterized that 

species. 

RenaJ/JJltia qracilis (Brongniart) Zeiller 19 likewise 

is similar to. the plant here discussed. The trilobed 

pinnules developed in some individuals, the sinuose 

rachis, the distant pinnules, and the texture agree well 

with the Colorado specimen. However, R. gvracilis 

is more delicate, and the pinnae are more triangular 

in outline. 

Sphenopteris footn.eri Marrat 20 is related 'to Sphenopteris cf. S. microcarp:a but is a more compact type 

with crowded pinnules and broadly triangular pinnae. It is with · difficulty separated from Splvenopteris gracili.~. 

Sphenopteris microcarpa Lesquereux appears to be 

restricted to the upper part of the Lykens coal group 

and its equivalents in the Appalachian region. In 

consequence the presence in the Weber ( ? ) of a species 

which is closely related if not identical strongly suggests a similar age. -

Occurrence: Bed 17 of Evans Peak section; collected by 

J. H. Johnson, 0. D. Hier, and C. B. Read. 

Sphenopteris asplenioides Sternberg 

Sphenopteris asplenioi.d;es Sternberg, Flora der Vorwelt, vol. 1, 

p. 16, 1825; vol. 2, pts. 5 and 6, p. 62, 1833. 

·white, U.S. Geol. Survey 20th Ann. Rept., pt. 2, p. 879, 

1900. 

Sphenopteris hoeningsha.usi Brongniart, Prodrome, p. 51, 1828. 

Fragmentary remains, "ghost" impressions, from 

locality 8050 are identical with S'phenop·teri8 asp·lenioides Ste:rnberg (Sphenopteris hoeringshausii Brongniart). 21 No evidence of any variation which might 

serve . to characteriz~ this species in its Cordilleran 

distribution has been noted in this material~ although 

elsewhere 22 there are kriown to occur very small forms 

' which may deserve varietal rank. 

10 Brongniart, Adolphe, Histoire des vegetaux fossiles, vol. 1, p. 197, 

pl. 54, fig. 2, 1829. Zeiller, R., Fructifications des fougeres du terrain 

houiller: Annales sci. nat., 6th ser., Botany, vol. 16, p. 185, 1883. 

Kidston, Robert, Fossil plants of the Carboniferous rocks : Geol. Survey 

Great Britain Mem., Paleontology, vol. 2, pp. 310-313, pl. 79, figs. 1-5, 

1923. 

20 Marrat, F. P., On the fossil ferns in the Ravenhead collection: 

Liverpool Geol. Soc. Proc., 1871-72, vol. 2, p. 101, pl. 8, figs. 2, 3, 1872. 

Kidston, Robert, Fossil plants of the Carboniferous rocks : . Geol. Survey 

Great Britain Mem., Paleontology, vol. 2, pp. 117-120, pl. 24, figs. 1, 1a, 

1b, 2-6 ; pl. 25, fig. 5, 1923. 

21 See White, David, op. cit., p, 879, for explanation of this nomenclature. 

22 The collection referred to here was made by David White and the 

writer from the Weber(?) shale~ in th~;J Ark;msas River Canyon n~~f 

Wellsville Springs, Colo, 
86 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 19 3 4--3 5 

As Sphenopteri.~ asplenioides Sternberg' has been 

described by several writers,23 a discussion of its taxonomic characters is npt necessary in this paper. It is 

sufficient to point out that this species is important in 

indicating the age of the beds from whch it was collected. In the Appalachian region it is characteristic 

of the Pottsville group and is not known to range 

. higher. Therefore the occurrence of S. asplenioides 

Sternberg in the lower part of the Weber (?) formation may be taken as strong evidence of the early 

Pennsylvanian age of the basal pqrtion of the section. 

Occurrence·: Bed 5 of Pennsylvania Mountain section; collected by J. H. Johnson, 0. D. Hier, and 0. B. Read. 

Sphenopteris cheathami (Lesquereux) Read, n. comb. 

~late 16, figure 5, d; plate 17, fig~res 1-4 

Ercmopter i s chea-thami Lesquereux, 2'd Pennsylvania Geol. 

Suney Rept. P, vol. 3, pp. 770, 853, 889, 919, pl. 104, figs. 

2--4, 1884. 

White, U.S. Geol. Survey 20th Ann. Rept., pt. 2 pp. 870-

871, 1900. ' 

Fronds of medium size, probably broad-lanceolate 

or triangular, bipinnate or tripinnate, rachis flexuose, 

small; primary pinnae laneeolate with acutely rounded 

apices, the axis narrow, irregularly rugose, and flexuose. Secondary pinnae distant, alternate, at right or 

slightly acute angles to the rachis, linear-lanceolate, 

the margins subparallel and tapering gradually from 

the base to the narro.w ly rounded apex, the axis small, 

sulcate above, slightly and irregularly crenulate both 

longitudinally and transversely. Pinnules alternate 

or subopposite, crowded in distal portions of the frond, 

. broadly cuneate, elongate-oval, or oval, decurrent, 

often bilob-ed or: trilobed, the lobes never cleft below 

the middle of the pinnule, apices bluntly rounded, 

com~only irregularly crenate 2 serrate, or erose, lateral 

margins entire; venation indistinct, basal veins apparently dichotomizing several times while crossin<Y 

lamina to distal margin; each lobe plurinerved; pin~ nules, connected by narrow rachial wings, which become suppressed in proximal regions. 

Sphenopteris cheathaoni (Lesquereux) is abundant 

at locality 8049, where the most productive parting i~ 

littered with impressions of pinnules and fragments of 

pinnae. Figure 4 reproduces one of the largest specimens in the collection. It will be ·seen that the frond 

is polypinnate and has a lax habit. The rachides of 

the pinnae are noticeably slender in proportion to the 

size of the plant. The cuneate, usually lobed pinnules, 

are conspicuous. 

Figure 1 illustrates fragmentary pinn.ae which 

plainly demonstrate the nature of the pinnules. These 

23 Sternberg, Kaspar, Flora der Vorwelt, vol. 1, p. 16, 1925. Brongniar_t, Adolphe, Prodrome, p. 60 (51), 1828_; Histoire des veget~J,UX 

fossiles, vol. 1, p. 199, pl. 52, 1829. Kidston, Robert, Fossil plants 

of the Carboniferous rocks : Geol. Survey Great Britain Mem., Paleontology, vol. 2, p. 115, pl. 23, figs. 6, 6a, 1923. 

are chiefly ovate-cuneate and are _somewhat irregularly serrate distally. ]'igure 3 shows another fragment from . the apex of a large pinna. It will be remarked that in general aspect the pinnules are unlike 

those of figure 1. These figures rna y be taken to indicate something of the range of variation. 

Figure 2 is an enlarged view of the specimens shown 

in figure 1 and shows some of the details of pinnule 

arrangement, shape, and nervation. The bilobed and 

trilobed compact pinnules seated decurrently on the 

rachis are connected by narrow axial wings. 

This species is· identical with Lesquereux's Eremopteris oheathami. 24 The Colorado plant is a somewhat 

larger type than that prevalent in the Pottsville, although occasional specimens are met with which are 

fully as robust. 

Lesquereux's concept of the genus Eremopteris 

Schim per was an extremely broad one, as is attested 

by his insertion of the species here discussed in that 

genus. His definition, "Upper part of the :·.fronds 

dichotomous; pinnae open or oblique, irregula~ly pin- . I 

natifid; laciniae long, obovate or wedge-form, the 

lower ones deeply cut,"25 obviously includes ~ much 

larger and heterogeneous assemblage than is now 

admitted in Eremopteris . . The recommendation of 

White in 1899 that Eremop,teris should be restricted to 

a small group of plants which conform strictly to E. 

mrtemisa"efolia (Sternberg) Schimper is more i:h keeping with current taxonomic practice and is adopted 

· in this paper. A less rigid usage deprives the genus 

of its significance. Certainly the " E. cheathami" of 

Lesquereux is f~r removed from the typical form of 

the genus referred to above and is closely related in 

its general structure to that group of sphenopU:(rids 

typified by Sphenopteris obtruJ8ilob(]),, 

Sphenopteris che(]),thami is distinct in America and 

cannot be readily confused with European species. 

It is perhaps related to certain undescribed Pottsville 

species, but a comparison with these cannot be made 

here. Sphenopteris valida Dawson 26 resembles this 

plant in some respects but not so closely as to cause 

confusion. Sphenopteris sauveuri Crepin 27 is also of 

the same general stock as S. cheath.arrui but differs in 

the more lax appearance and more deeply lobed pinnules. 

Sphenopteris cheathami (Lesquereux) is recorded by 

White 28 from the lower, intermediate, and upper 

24 Lesquereux, Leo, op. cit., pp. 77{}-771, pl. 94, figs. 2-4. 25 Lesquereux, Leo, Description of the coal :liora of the Carboniferous formation in Pennsylvania : Pennsylvania Second Geol. Survey 

Rept. P, vol. 1, p. 292, 1880. · 26 Stopes, M. C., The "Fern Ledges" Carboniferous flora of St . 

.Tobn, N.B.: Canada Geol. Survey Mem. 41, pp. 34-36, pl. 9·, fig. 21; pl. 

10, figs. 22-23, 17914. 27 Crepin, Fran~ois, Observations sur quelques SphfmOPteris et sur 

les cotes des Calamites: Soc. roy. bot. Belgique Bull., vol. 19, p. 54, 

1880. 28 White, David, The stratigraphic succession of the fossil floras of 

the Pottsville formation in the southern anthracite coal field, Pa. : U.S. 

Geol. Survey 20th Ann. Rept., pt. 2, pp. 78{}-781, 1900. 
'f 

A FLORA OF POTTSVILLE AGE FROM THE MOSQUITO RANGE, COLORADO 87 

parts of the Lykens coal group of the Pottsville formation of eastern Pennsylvania. Its occurrence in 

lower part of the weber ( n furnishes excellent evi· 

dence of the Pottsville age of at least that part of the 

formation. 

Occurl"ence : Bed 17 of Evans Peak section ; collected b;y 

.r. H. Johnson, 0. D. Hier, and 0. B. Read. 

Diplotmema patentissima (E.ttingsha.usen) Stur 

Plate 16, figure 3 

Hymenophyllitoo vaten/ issrimvus Ettingshausen, K. Akad. Wiss. 

. Wien, l\1ath.-naturwiss. Cl., Denkschr., Band 25, p. 26, 

fig. 13; pl. 7, fig. 4, 1865. 

Rphenopteris (Hyme1WphyZlites) patentissima Schimper, Traite 

de paleontologie vegetale, vol. 1, p. 407, 1869. 

Rhodea patentissima · Stur, K.-k. geol. Reichsanstalt Abb., 

Band 8, Heft 1, p. 36, pl. 9, figs. 1-9, 1875. 

Renault, Cours de botanique fossile, vol. 3, p. 193, pl. 33, 

fig. 12, 1883. 

Hoffman and Rhyba, Leitpfianzen, p. 43, pl. 6, fig. 1, 1899. 

Dip~otmerna. patentis·sirn.a. Stur, op. cit., Heft 2, p. 234, 1877. 

Kidston, Geol. Survey Great Britain Mem., Paleontology, 

Yol. 2, pt .. 3, pp. 253-254, pl. 54, figs. 5-6 ; pl. 56, figs. 

4, 4a, 1923. 

Hphenopte1'is pa.tentissima Schimper, in Zittel, Handb'uch der 

PaUiontologie, Abt. 2, p. 108, fig. 76, 1890. 

White, U.S. Geol. Survey 20th Ann. Rept., pt. 2, p. 880, 

pl. 188, fig. 1, 1900. 

Frond and primary pinnae unknown in the pres8nt suite of specimens. Pinnules alternate, somewhat 

imbricate, open rhomboidal-rounded in outline but 

modified by deep dissection into linear lobes ; the 

larger p~nnules divided into 8 to 12 narrow, digitate 

segments, the smaller, more distant ones often reduced 

to a simple or once dichotomous lamia, all gradations 

between these extremes being found in th~ intermediate 

portions of the pinna. Segments divergent, margins 

parallel or nearly so, gradually converging upward 

to a rounded apex·. A single vein which is decurrent on the rachis enters each pinnule and forks to 

supply each lobe with one nerville. Epidermis scaly 1 

the scales parallel to veins and tending to obscure 

them. Texture thin, coriaceous (?). 

Several fragments in the collections clearly indi 

cate the presence of a diplotmemoid plant with the 

essential features of Diplotmema. patentissitma (E.ttingshausen) Stur. The. figure illustrates the nature 

of the plant. The pinnules are lax and are cleft into 

numerous linear lobes, giving the. lamina a digitate 

appearance. The.se lobes are uninerved and are coverad with small scaly protuberances which are oriented 

parallel to the veins and tend to obscure them. This 

feature was pointed out by White 29 as being very 

characteristic of the species. It is mare strongly 

emphasized in the Colorado material than in specimens from the. Pottsville of the Appalachian region and 

.suggests that the plant may be distinct. It does not 

ro White, David, op. cit., p. 880. 

seem advisahle to describe a new species or variety on 

such obscure fragments, however, so it has been retained in Stur's species, from which it can be segregated if additional material makes it necessary. 

In several respects the Weber ( ? ) plant resembles 

Sphenopteris fwrcata Brongniart,30 Sphevnopteris royi 

Lesquereux, 31 Rhodea, smithii Kidston,32 and Zeilleria mora/oica (Ettingshausen) Bureau,33 but it can 

be separated by the decidedly lax and spreading pinnules. S. furcata is more compact, and the pinnules 

are usually less deeply incised and are chiefly sessile 

on the pinna axis. In S. royi the ultimate divisions 

of .the pinnules are more acute than in Diplotmema 

patentissima, and the latter is distinguished from Z. 

moravica by the larger and laxer pinnules. 

Dip.Zotmema patentusima occurs, according to 

'White, 34 in " the lower portions of the very thick 

sections of the Pottsville series in the' Virginia, Tennessee, and Alabama regions, as well as in the southern .anthracite field of Pennsylvania." In other 

words, it is a typical Pottsville species, and its presence may be taken as jndicative of the Pottsville age 

of the Weber ( ? ) beds from which it was collected~ 

Occurrence : Bed 17 of Evans Peak section ; collected by 

J. H. Johnson, C. D. Hier, and C. B. Read. 

Gemus A:DIANTITES Goeppert, emended 

Adiantites Goepp~rt (part) l Systema filicium fossilium, pp. 

173, 216, 1836. 

Ad,iantides Schimper (part), Traite de paleontologie V'egetale, 

vol. 1, p. 424, 1869'. 

"Ad,iantites" is used as a generic designation which 

includes types of fossil plants characterized by cuneate or wedge-shaped pinnules, sessile or attached to 

the rachis by a foot stalk. The pinnules are usually 

entire or slightly lobed but occasionally may be deeply 

incised. The venation consists of several radiating 

' and frequently dichotomizing nerves, there being no 

definite central strand. The plants were often rather 

large and bore rank foliage. Adiantites is to be regarded as a form genus rather than a natural one. 

Some, at least, of the plants falling within it are 

cycadofilic. This has been proved by 'White 35 for 

Aneimites ( W ardia) fertilis, a form very similar to 

some species of Adimntites. 

The validity of the generic name "Adimntites " is 

questionable, because Goeppert first used it for Ginkgo 

30 Brongniart, Adolphe, Prodrome, p. 59 (50), 1828 (nomen nudum) ; 

Histoire des vegetaux fossiles, vol. 1, p, 179, pl. 49, figs. 4-5, 1829. 31 Lesquereux, Leo, Description of the coal fi,ora : 2d Pennsylvania 

Geol. Survey Rept. P, vol. 3, p. 768, pl. 104, figs. 7-10, 1884. 32 Kidston, Robert, ll'ossil plants of the Carboniferous rocks : Geol. 

Survey Great Britain Mem., Paleontology, vol. 2, p. 226, pl. 56, figs. 

1-2; pl. 57, figs. 2-3, 1923. . · 33 Bureau, Edouard and Louis, Excursion du 7 septembre a Oudan, 

Ancenis, Mesongen, Cap-Chaux, Mouzeil: Soc. geol. France Bull., ser. 

4, vol. 8, p, 65a, 1908 . 

34 White, DaYid, op. cit., p. 880. 35 White, David, The seeds of Aneimites: Smithsonian Misc. Coll., vol. 

47, pt. 3, pp. 3!~2-331, pis. 47-48, 1904. 
88 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 19 3 4-3 5 

digitata, a Jurassic plant. However, long usage as 

the generic designation for plants of the type described above has made it desirable to retain the genus 

in the ~mended sense. 

Adiantites rockymontanus Read, n.sp. 

Plate 18, figures 5, 6 

Fronds and pinnae unknown, probably largre. Pinnules of medium size, 12 to 15 millimeters long and 

6 to 8 millimeters broad, cuneate, the apices rounded 

and shallowly trilobed or slightly bilobed and giving 

the .lamina an obcordate outline; sides straight or 

slightly convex; base wedge-shaped, narrow, attenuate, 

probably decurrent, 8 to 11 millimeters long and 2 to 

3 millimeters wid~. Venation regularly dichotomous, 

a single vein passing into the base of the pinnule, bifurcating immediately to form branches which by 

frequent dichotomy supply the pinnule ·with numerous slightly arched, closely spaced veins passing to the 

distal margin, where they are spaced 3 to the millimeter. Texture markedly coriaceous,· the veins prominent and the surface corrugated. 

Adriantites rockymonta,nus is one .of the most interesting species in the Evans Peak collection and provides an element of speculation concerning the age of 

the beds. Figure 5 reproduces a complete and wellpreserved pinnule of the plant. Its distinctly cuneate 

outline and the corrugated appearance· are very conspicuous characters. The apex is trilobed, although 

not conspicuously so. Basally the lamina tapers into 

a broad and heavy stalk, the length of which cannot 

be determined. 

The details of venation are well shown in figure 6, 

which is an enlarg~d view of one of the pinnules. 

The frequent dichotomies are well shown, and the 

peculiar corrugated surface is very plain. 

AdJi(J;ntites rockymontanu.rs appears to be genetically 

related to Adiantites adiantoides (Lindley and Hutton).30 They are not to be confused, however, the pinnules of the Colorado form being narrower and developing a trilobed, narrowly obtuse apex of a type 

not figured or described in A. adiantoides. Also A. 

rockymontanrus has more crowded veins, and the pinnules apparently are thicker and harder in texture; 

The corrugated appearance of the pinnules is very distjnctive. The elongate base, which suggests a decurrent attachment on the rachis, is another characteristic at variance in A. r.ocky1nontanus and A. advantoides, the latter developing a short pinnule base 

which is slightly, if at all, decurrent~ 

The possibility of an affiliation of Adiantites rocky1nontanus with species of the genus Aneimdtes has . 

sa Lindley, John, and Hutton, "Villiam, Fos•sn flora of Great Britain, 

vol. 2, p. 91, pl. 115, 1834 (Sphenop,teris adiantoicles). Kidston, Rob· 

ert, Fossil plants of the Carboniferous rocks: Geol. Survey Great 

Britain Mem., Paleontology, vol. 2, pp. 190-191, pl. 45, figs. 3-4a; pl. 

46, figs. 1-2, 1923. 

been considered carefully. To the Pocono species~ 

Aneimites spectabilis White ms., there is marked similarity. In view of the questionable status or "Aneimites" as a aeneric name it seems best at the present 0 .• time to assign this species to Goeppert's genus Ill 1ts 

emended sense. 

· As has already been stated, Adiantit'es rocky?nonf(l(n'UJS has a critical bearing on the age of the plant 

beds. It is strongly suggestive of Mississippian types, 

particularly Aneimites spectabilis, and suggests caution in assignin a the age of the beds to a position very 

high in the Pe~nsylvanian. On the other hand, its 

affinity with Adi~ntites adiantoides, which is of vV estpha1ian and Lanarkian age, furnishes ample justification for the assignment of Pottsville age to the enclosing beds. 

Occurrence : Bed 17 of Evans Peak section ; collected by 

J. H. Johnson, C. D. Hier, and 0. B. Read. 

CORDAITALES 

Cordaites sp. 'I 

Plate 16, figure 5b 1 

The material of Cordaites which has so far been 

obtained from Evans Peak and Pennsylvania Moun-. 

tain is limited to several incomplete leaves of what is 

probably a new species. In figure 5b such a frag.-

ment is illustrated. The leaf is rather narrow and 

is of an unknown length. The venation is similar to) 

that of Cordaites robbii Dawson 37 but is so~ewhat: 

finer. The coarse nerves, which are usually 3· to the.: 

millimeter, alternate wit.h indistinct fine nerves. Al-. 

though it is possible that the specimen figured, as well 

as others in the collection, may be identical with. 

Cordaites robbii, the evidence is not convincing to the 

writer. Cordaites robbii is usually a larger, broader· 

type than the Weber ( ? ) plant and, as has been stated. 

above, differs somewhat in venation. Specific identification has been deferred until additional material. 

can be obtained. 

O::!currence: Bed 17 of Evans Peak section; collected by;-

J. H. Johnson, C. D. Hier, and C. B. Read. 

Cordaicarpon sp. 

Plate 16, figure 6 

Seed very nearly flat, ovate, 11 + millimeters long-:· 

and about 14 millimeters broad, broadly winged; ~ 

seed proper fusiform, elongated with longitudinal axis: 

of fructification, 4 to 5 millimeters long and 2 milli- . 

meters broad, located centrally and entirely sur- . 

rounded by wing. This wing nearly circular, 6 to 8 ~ 

millimeters in width, becoming slightly broader near , 

87 Dawson, J. W., On the flora of the Devonian period in northeastern 

America: Geol. Soc. London Quart. Jour., vol. 18, p. 316, pl. 14, figs ~ · 

31a-c, 1862; Acadian geology, 2d ed., p. 544, fig, 1.~ ~' · ,1868 .. , 1 
A FLORA OF POTTSVILLE AGE FROM THE MOSQUITO RANGE, COLORADO 89 

the base, not entirely preserved but apparently entire 

and rounded. 

This species, which is represented by a single specimen, is almost certainly new. In view o:£ the poor 

preservation, which has prevented a detailed description, it has been considered best to list the seed simply 

as 0 orrlaicaYrpon sp. The most conspicuous :feature 

o:£ the seed is the nearly circular form of the· wing, 

i1lustrated in figure 6. It is apparent that this is one 

of the large, wide-winged species of the type of 0 ordaic(lff'pon newberryi,38 0. ph'ill!ipsi,39 and C. baileyi.40 

It is, however, distinct from any which the writer has 

so far observed. According to White this group is 

particularly characteristic of the upper Lykens or 

Sewanee coal zone of the Pottsville group and hence 

furnishes evidence in favor of the assumption that 

the flora is Pottsville. in age. 

Occurrence: Bed 17 of Evans Peak section ; collected by 

J. H. Johnson, C. D. Hier, and C. B. Read. 

Cordaianthus sp. 

There are two poorly preserved fragments of Oordaianthrus in the collection from locality 8049 which 

cannot be specifically determined. The better specimen has a heavy tapering axis, the surficial features 

of which are nearly obliterated. It bears numerous 

crowded, fertile branches subtended by large sterile 

bracts. The strobili are of medium size and are 

nearly sessile on the axis. Their characteristics cannot be established with the material at hand. In general aspect there is a resemblance to 0 ordaianthu.s 

bacoifer Grand'Eury,41 a group to which it probably 

belongs. It is not, however, specifically identical with 

that fossil, differing in the broader axis and the larger 

"spike" of strobili. Any further comparison seems 

unnecessary with the poor material now representing 

the :form. 

Occurrence: Bed 17 of Evans Peak section; collected by 

J. H. Johnson and C. D. Hier. 

POSITION UNCERTAIN 

PALAEOPHYLLALES 

Trichopitys whitei Read 

Plate 16, figure 5a; plate 18, figures l, 4 

Trichopitys whitei Read, Washington Acad. Sci. Jour., vol. 23, 

pp. 461-463, 1933. 

Leaves more than 80 millimeters long and 80 n1illimeters wide, obtriangular, deeply dissected into numerous linear lobes; narrow at . base but expanding 

rapidly to bifurcate into subequal lobes about 2 milli38 Andrews, E. B., Descriptions of fossil plants from the coal measures of Ohio : Ohio Ceol. Survey Rept. 2, pt. 2, Paleontology, .p. 425, 

pl. 46, fig. 2, 1875. 

a9White," David, op. cit., p. 907. 40 Dawson, J. W., Acadian geology, 2d ed., p. 554, fig. 194 D, 1868. 41 Grand'Eury, F. C., Flore carbonifere du departement de la Loire, 

pp. 230-231, pl. 26, 1877. 

meters · in breadth, these soon forking again into two 

unequal lobes which bifurcate at least once or twice, 

the apices not being preserved intact, these equally 

dichotomous, forking at an angle of about 30°, contracting gradually to acute terminations. Nervation 

consisting of two basal veins dichotomizing to ·supply 

the primary lobes with three or four veins, which further dichotomize to supply subterminal and terminal 

lobes with one to three veins, all of these large, prominent, spaced evenly on lamina. Texture apparently 

coriaceous; base and_lobes thick and rounded in cross 

section. 

The reference of the peculiar leaves shown in figure 5a to Trichopitys is based on the facts concerning 

this genus which have been accumulated by Saporta,42 

Renault,43 ]9"'eistmantel/4 and others. The actual discrimination between Trichopitys and Dicranop hyZlwm 

is extremely difficult when sterile leaves only are present. In fact, when the plant described here was first 

examined it was called Dicranophyllwm, and on very 

good grounds. I£ the :fructifications and fertile appendages are disregarded, as all the Colorado material 

is vegetative, the distinction between these genera 

lies in the greater symmetry, more equal dichotomy, s1naller size, and, in general, greater rigidity 

of Dicranophyllium, together with the more crowded, 

~pirally arranged leaves. This last criterion is of 

~light value in general practice, owing to the . usual 

occurrence of the remains as detached laminae. 

Plate 1Q, figure 5, is a photograph o:£ a. specimen of 

shale on which two speGimens of Trichopity8 whitei 

are exposed. Numerous comminuted remains of this 

and other plants are likewise to be seen. The small 

size of Trichopitys whitei is at once apparent: Most 

of the species that have previously been placed in this 

genus. are rnuch larger, to judge from published fig .. 

nres. Another :feature of importance is the apparently short base. The matrix and nature of preservation o:£ the leaves do not allow a complete uncovering o:f the specimens, but the bases cannot be 

very attenuate. This is also in contrast to many representatives of the genus. 

Plate 18, figure 1, shows one o:£ the speclmens on 

the slab at a magnification of 3 diameters. The plurinerved, diehotomous venation is indistinctly shown, 

and the fanlike expansion of the blade is also apparent, as are the numerous dichotomies. 

In figure 4, plate 18, there is shown a fragment of a 

leaf in which the more distal portions of a lamina 

are exposed. It will be seen that the apices are narrowing to acute terminations. 

42 Saporta, Gaston de, Sur Ia decouverte de deux types nouveaux de 

coniferes dans les schistes permiens de Lodeve : Compt. Rend., vol. 80, 

p. 1020, 1875. 48 Renault, B., Cours de botanique fossile fait au Musee d'histoire 

naturelle, vol. 4, pp. 64-65, 1885. 

44 Feistmantel, Otakar, Uhenosne Utvary V Tasmanii, p. 113, 1890. 
90 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 19 3 4-3 5 

Trichopitys wrhiteiis distinct from any other species 

that have come to the writer's observation. Tricho·pitys millerensis B. Renault 45 is comparable but differs 

in its smaller size, greater laxity, and details of venation. Triohopitys jlJhnstoni Feistmantel 46 is similar 

in size · but has a much longer base and a narrower, 

more regularly dichotomous blade. 

As this is the first record o£ Trichopitys in North 

America, it is desirable to summarize the opinions 

that have been expressed concerning the affinities of 

this peculiar genus. Trichopitys has usually been 

placed in the Ginkgoales, the basis for this assignment 

bEdng found in the similarity of the leaves to those 

of the Mesozoic Ozekanowrskia. The criterion of leaf 

form is not always exact, and it is felt that there is 

not sufficient justification in this case for the inclusion. In describing Triohopitys heteromorpha Saporta, Zeiller 47 says : 

La meme espece a offert, a. l'aisselle des feuilles, des axes 

munis de courts ramules lateraux dont chacun se termine par 

une graine ovo!de ; la valeur morphologique de ces axes reste 

malheureusement indecise, bien qu'il semble naturel de voir 

en eux des organes foliares transformes. 

These fructifications, representing either seeds or 

megaspores and associated tissues, occur, as Zeiller 

states, in the axils of leaves, if it is possible to judge 

from the figures. They are perhaps comparable to abnormalities that have been observed in the ovulate 

shoots of Ginkgo biloba, although this comparison is 

far-fetched. 

A rather puzzling situation is introduced by Kiltorke1U3ia devonica Johnson. This plant, which combines 

the characters o£ Trichopitys and G-inkqophyllwm into 

what is apparently a single dimorphic, compound lea£, 

is almost surely a pteridosperm.48 The author of the 

genus was of the opinion that it was an ancestral 

ginkgoaceous stock, but this opinion is scarcely tenable. 

The Trichopitys' type of leaflet which is developed in 

this plant is a clear demonstration of gross morphologic similarity in widely separated stocks. The occurrence o£ detached leaves of both Trichopitys Saporta and Dactylophyll!wm in the Weber ( ? ) collections has brought up the question whether these should 

be placed in two distinct genera or in a single species 

under the heading K iltork'ensia. The former stand 

has been taken on the ground that the two have not 

been· observed in connection and that TrichopityS' and 

Ginkgophyllwm are in usually distinct genera, al45 Renault, B., Bassin houiller et permien d'Autun et Epinac, atlas, 

pl. 82, fig. 2, 1893 ; text, p. 378, 1896. 

46 Feistmantel, Otakar, Uhenosne utvary V Tasmanii, p. 113, pl. 10, 

figs. 4-5, 1890. 

47 Zeiller, C. R., Elements de paleobotanique, p. 254, text .fig. 182, 

1900. 48 Johnson, Thomas, Spermolithus devonicus, gen. et sp. nov., and 

other pteridosperms from the Upper Devonian beds at Kiltorkan : Roy. 

Dublin Soc.. Sci. Pro c., new ser., vol. 15, no. 23, pp. 249-251, 1917. 

See also Seward, A. C., Fossil plants, vol. 4, p. 88, 1919. 

t~ough the strength of the alternative stand cannot 

be denied. 

There can be no doubt that the relationships of 

Trichopitys are obscure. Therefore the group name 

"Palaeophyllales " 49 has been adopted, as it is noncommittal and implies no relationships. 

The geologic range of Trichopitys is not exactly 

known at present. It has a sporadic occurrence in the 

Carboniferous and Permian and apparently range$ 

into the lower Mesozoic. 

Occurrence : Bed 17 of Evans Peak section ; collected by 

J. H. Johnson and C. D. Hier. 

Genus DACTYLOPHYLLUM Read, n. gen. 

Plate 18, figures 2, 3 

" Daotylophyllwm " 'is the nam~ proposed for a ve·ry 

unusual type of leaf which was collected at locality 

8050. The exact affinities of the plant, figures of 

which are here given, are a matter of no little interest 

and are highly. problematic. 

The leaf o£ the genotype, DactyZophyllum johnsoni, 

which is described below, is a digitate type,. in outline 

not unlike certain Mesozoic species of Baiera. The 

venation, on the other hand, departs from Baiera in 

being much simpler and lacks the strong marginal 

strapds that ch~racterize most o£ the accepted ginkgoaceous leaves. The generic characters are as 

follows: 

Leaf small, obtriangular, dissected into similar 

lobes, the base contracted into a flabby petiole(~) of 

unknown length, primary lobes dichotomous several 

times, the ultimate lobes linear and straplike. N ervation simple, two veins at the base giving rise to primary lobe venation by one or two regular dichotomies 

and giving rise to the venation of the lobes of the next 

higher order by further dichotomies just below each 

bifurcation of the lamina. Ultimate lobes with .two 

to four veins. No distinct marginal veins o£ the type 

~haracteristic of Ginkgo observable. 

Although ·n{]Joty,lophyllum is very similar in aspect 

to Baiera, in the writer's opinion its affinities probably 

Jo not lie with the Ginkgoales. A number of genera 

tentatively referred to the Ginkgoales have been described from the Paleozoic. Among these are Ginlcgophyllwrn, Triohopity'S, Dicranophyllum, Psygmophyllwrn, and Kiltorkensia. Without discussing the 

merits of these forms as putative Ginkgoales, it suffices 

to say that Dactylophyllwm is distinctly different from 

any o£ them, although it approaches Ginkgophyllwm 

and Kiltorkensia in certain respects. Its affinities may 

lie in the direction of the Pteridospermae, but this is 

. •o Arber, E. A. N., On Psygmop,hyllum majus sp. nov. from the Lower 

Carboniferous rocks of Newfoundland, together with a revisiOJl of the 

genus and remarks on its affinities: Linnean Soc. London Trans., vol. 

7, pt. 18, p. 405, 1912. 
A FLORA OF POTTSVILLE AGE FROM THE MOSQUITO RANGE, COLORADO 91 

problematic. For the present the writer prefers to 

assign the genus to Arber's Palaeophylll'les, which is 

a noncommittal order erected for such forms. 

Dactylophyllum johnsoni Read, n. sp. 

Plate 18, figures 2, 3 

Leaf small, obtriangular, deeply cleft into two primary deltoid lobes; these .further cleft into linear, 

straplike segments which are truncate or obtusely 

rounded apically and developed by slightly irregular 

dichotomy. Base somewhat attenuate and narrow. 

Venation at base o.f two ( ~) distinct veins, each of 

which furnishes the .supply of one of the primary 

lobes and by dichotomy below the medial cleft gives 

rise to plurinerved (2 or 4) lobe bases; repeated 

dichotomy below each bifurcation of the lamina resulting in binerved or quadrinerved ultimate lobes. 

Intermittent dichotomies rare. Texture thin. 

In figure 3 the general aspect of DactyZophyllum 

johnsoni is .shown. This recalls numerous Mesozoic 

species of Baiera and in particular Baiera gracilis 

(Bean) Bunbury. The leaf is small, obtriangular, 

and deeply dissected into linear lobes. Basally it is 

contracted into a narrow attenuation. It is not clear 

whether this represents a broad-winged petiole or 

.simply the base of the leaf. 

Figure 2 represents the same leaf at a magnification 

of 3 times. The lobes; it will be noted, are dichotomous, although somewhat irregularly so. The venation is indistinctly shown. Two veins are present at 

the base and give rise to the venation of the two primary lobes. As these pass to the distal margin they 

dichotomize below each bifurcation of the leaf and 

occasionally in between, as the ultimate divisions may 

carry four veinlets. 

There is consider~ble support for the argument 

that the Ginkgoales were present in Paleozoic time. 

Such genera as PsygmophyZl'l1YI1'h,50 Ginkgophyllum,51 

Baiera,52 Glo.Uophyllwrn, 53 Neplhropteris,53 Rhipidop50 Schimper, W. P., Traite de paleontologie vegetale, vol. 2, p. 192, 

1870. 1 Saporta, Gaston de, Sur la decouverte de deux types nouveaux de 

coniferes dans les schistes permiens de Lodeve : Compt. Rend., vol. 80, 

p. 1017, 1875. 

52 Braun, C. F. W., Beitrli.ge zur Petrefactenkunde Bayreuth, Heft 6, 

p. 20, 1843. 

53 Zalessky, M. D., Plants from the coal-bearing deposits of Sudzenka, 

Siberia: Soc. nat. Oural Bull., pt. 4, p. 28, 1912 

sis, 54 Trichopitys,55 and Dicranophyllum 56 are held by 

some investigators to furnish positive proof of the 

existence · of this order at ari. early date. However, 

there are not sufficient data to prove positively the 

systematic position qf all these genera. Seward,57 in 

commenti.ng on the situation, writes that "several 

Paleozoic genera * * * have been assigned to the 

Ginkgoale~ on evidence which in most cases is wholly 

inadequate . " 

The discovery in the Upper Devonian grits of Ireland of slender forked leaflets similar to the leaves of 

Triohopitys or Dicranophyllwrn attached to a rachis 

also giving off "Psygmophyllum" leaflets 58 has an 

important bearing on the present case. The plant, 

K iltorkensia devonioa Johnson, is regarded by Johnson as an ancestral gin,kgoaceous stock, but it is more 

probably a, pteridosperm with p-olymorphic pinnules. · 

It is not unlikely that other Paleozoic Ginkgoales 

have similar affinities. Both Trichopitys and Dactylophyllum occur in the Weber ( ~) beds at the same 

locality, so it is possible that they represent a single 

species allied to K. devonica. 

On the other hand, if DactylophyZlwm johnsoni is · 

actually a primitive representative of the Ginkgoales 

it is important in being an old record of a genus that 

was common in the Mesozoic. There are species of 

PsygmophryZlum which antedate this, but they are 

much more open to question as regards their affinities. 

Dactylophyllwrn johnsoni does not allow careful comparison with the occasional species of Baiera from 

the Perm.ian. Both Baiera raymondi Renault 59 and 

Baiera. virginiana Fontaine and White 60 are distinct. 

Its most striking resemblance is to a small leaf of 

Baiera gracilis (Bean) Bunbury, but this is not close. 

Occurrence : Bed 17 of Evans Peak section ; collected by . 

J. H. Johnson and C. D. Hier. 

54 Schmalhausen, J., Beitr.age zur Jura-Flora Russlands: Acad. imp. 

1 sci. St.-Petersbourg Mem., ser. 7, tome 27, no. 4, p. 50, 1879. 56 Saporta, Gaston de, op. cit., P. 1020. 

oo Grand'Eury, F. C., Flore carbonifere du departement de la Loire, 

p. 272, 1877. 

57 Seward, A. c., Fossil plants, vol. 4, p. 76, 1919. 

us Johnson, Thomas, Spermolithus devonicus, gen. et sp. nov., and 

other pteridosperms from the Upper Devonian beds at Kiltorkan: Roy. 

· Dublin Soc. Sci. Proc., new ser., vol. 15, no. 23, pp. 2191-220, pl. 14, 

fig. 3, 1917. 

so Renault, B., Les plantes fossiles, p. 234, 1888. 

ao Fontaine, w. M., and White, I. C., The Permian or upper Carboniferous :flora of West Virginia and southwestern Pennsylvania: Pennsylvania Second Geol. Survey Rept. Progress, pp. 103-104, pl. 37, figs. 

11-12, 1880. 
PLATES 16-18 

93 
PLATE 16 

Pago 

FIGURES 1, 4. Lepidostrobus weberensis Read, n. sp. Fragments· of trobili with the central axis exposed. Note the slen- . 

derness of the woody cylinder and the shape of the sporophyll cushions. U.S. Nat. Mus. 39155_______ 82 

l!"'IGURE 2. L epidostrobus web erensi s Read, n. sp. A fragment showing ·the external appearance of a strobilus. U.S. Nat. 

~Ius. 39155---- ------------------ ---- ---------- -- -------~~ --- ------ -- ------------------~ -- -------- 82 

FIGURE 3. Diplotmema patenti ssima (Ettingshausen) Stur. A portion of a pinna showing the extreme dissection of the 

lamina. The specimen is in addition somewhat macerated. U.S. Nat. Mus. 39153--,..----------------- 87 

FIGURE 5. Trichorpitys wMtei Read, n. sp. A slab of shale bearing two specimens. Note the repeated bifurcations of the 

leaves, the small size, and the thickness of the lamina. a, Trichopitys whitei; b, Cordaites sp.; c, Stigmaria verrucosa; d, Sphenoptet·is cheathami (Lesquereux) Read, n. comb. U.S. Nat. Mus. 39156_ 89, 88, 82,86 

FIGURE 6. Oordaicarpon sp. Sketch of the seed slightly restored. U.S. Nat. Mus. 39162------------------------------- 88 

FIGURE 7. Neuropteris heterop,hylla Brongniart. Fragment of the distal portion of a pinna. U.S. Nat. Mus. 39160______ 84 

FIGURE 8. A.sterophyllites longifolius (Sternberg) Brongniart? Fragment of a whorl of leaves showing the essential 

characters. U.S. Nat. Mus. 39152-------------------------------------------------- _________________ 83 

94 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 185 PLATE 16 

6 7 8 

PLANTS OF POTTSVILLE AGE FROM THE MOSQUITO RANGE, COLO. 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER: 185 PLATE 17 ' 

PLANTS OF POTTSVILLE AGE FROM THE MOSQUITO RANGE, COLO. 
PLATE 1'7 

Page 

FIGURE 1. Sphenopteris cheathami (Lesquereux) Read, n. comb. Fragments of two pinnae showing outlines of pinnules . . 

U.S. Nat. Mus. 39158------------------------------------------------------------------------------- 86 

FIGURE 2. Sphenopteris cheathami (Lesquereux) Read, n. comb. Enlarged view of specimen in figure 1. U.S. Nat. Mus. 

39158 --------------.:_ ____ .:_----·-----------------·--------------------------------------------:--------- 86 

FIGURE 3. Sphenopteris cheathami (Lesquereux) Read, ri. comb. Fragment of distal portion of a large pinna. Compare 

the outline of the pinnules in this figure and figure 1. U.S. Nat. Mus. 3.9158-------------------------- 86 

FIGURE 4. Sphenopteris cheathami (Lesquereux) Read, n. comb. Large fragment of a secondary rachis bearing pinnae. 

Note the arrangement and spacing of the pinnae. U.S. Nat. Mus. 39158------------------------------ 86 

FIGURE 5. Neuropteris dluhosallli Stur. Fragment of a penultimate pinna. U.S. Nat. Mus. 39,16L_______________________ 83 

FIGURES 6, 7. Sphenopteri.s cf. S. mwrocarpa LeEquereux. U.S. Nat. Mus. 39154_________________________________________ 85 

95 
PLATE 18 

Page 

FIGURE 1. Trichopitys whitei Read. Enlarged view of specimen in figure 5, plate 1, showing venation. Note the thickness 

of the leaf. U.S. Nat. Mus. 39156_ _ _ _ _ _ _ __ _ _ __ _ _ __ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 89 

FIGURES 2, 3. Dactylophyllum johnsoni Read, n. sp. Note the similarity to some of the M~sozoic Ginkgoales. U.S. Nat. 

Mus. 39157---------------------------------------------------------------------------------- 91 FIGURE 4. Trichopitys whitei Read. Fragment of a leaf showing the apical dichotomies. U.S. Nat. Mus. 39156_________ 89 

FIGURES 5, 6. Adiantites rockymontanus Read, n. sp. A pinnule. Note the corrugated surface of the lamina. U.S. Nat. 

Mus. 39159---------------------------------------------------------------------------------- 88 

96 

0 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 185 PLATE 18 

PLANTS OF POTTSVILLE AGE FROM THE MOSQUITO RANGE, COLO.