Cretaceous Plants from Southwestern Colorado

GEOLOGICAL SURVEY PROFESSIONAL PAPER 221-D > Cretaceous Plants from Southwestern Colorado

By ROLAND W. BROWN

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1949, PAGES 45-66

GEOLOGICAL SURVEY PROFESSIONAL PAPER 221-D

A study offossil plants useful in determining the probable boundary between the Lower and Upper Cretaceous deposits

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1950 UNITED STATES DEPARTMENT OF THE INTERIOR Oscar L. Chapman, Secretary

GEOLOGICAL SURVEY W. E. Wrather, Director

For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. - Price 20 cents (paper cover) CONTENTS

Page Abstract-______45 Geological background. ______45 Age and significance of the fossil plants______47 Systematic descriptions..,-______48 Specimens of uncertain identity______52 Bibliography- ______53 Index.______65

ILLUSTRATIONS

Page Plates 9-12. Cretaceous plants. ._-_-----___---_-___-_-___-_-_-__.._-__---_.-___---_-______-_.__-______55-63 in

CRETACEOUS PLANTS FROM SOUTHWESTERN COLORADO

By ROLAND W. BROWN

ABSTRACT area, with maps and geologic sections, was published In southwestern Colorado a sequence of strata be­ by R. C. Coffin (1921) and further data and opinions tween the Jurassic carnotite-bearing Morrison forma­ concerning ages and correlations were published by tion (fMcElmo) and the Upper Cretaceous marine W. L. Stokes (1944, 1948). Generalized from Coffin Mancos shale contains fossil plants that are described and in his nomenclature, a composite geologic section here and used for determining the most likely position southwest of Nucla, Colo., includes the following se­ of the Lower Cretaceous-Upper Cretaceous boundary. quence of strata in descending order. The plants fall into two groups, the older, with the Geologic section near Nucla, Colo. conifer Frenelopsis varians Fontaine, indicating Lower Mancos shale. Dark JJpper Cretaceous marine shales with Cretaceous age, and the younger, with numerous ferns QrypUaea newberryi. These lie comformably on the Dakota and well-developed dicotyledons, characterizing the sandstone. early Upper Cretaceous. The boundary is probably at Dakota sandstone. Sandstone, shale, coal (some rninable), the top of the unit that Coffin called fPost-McElmo 100-200 feet of basal conglomeratic sandstone. Plants. and at the base of his overlying Dakota. f Post-McEHmo. Green to purple or somewhat varicolored shale, sandstone, limestone, dark shale, 100-200 feet of basal con­ GEOLOGICAL BACKGROUND glomeratic sandstone. Plants. The basal conglomerate, like that at the base of the Dakota, is a cliff-maker, and the Investigation during the past 30 years of the carno­ two may readily be confused under given circumstances. tite-bearing sedimentary rocks of the fMcElmo (now This conglomerate lies on an undulating fMcElmo surface. Morrison) formation of southwestern Colorado and At one locality, according to Coffin (1921, p. 112), Haly- menites was found in the sandstone not far above the adjacent areas in Utah has resulted in the collection of fMcElmo-fPost-McElmo contact, thus indicating a tem­ plants from different horizons in the strata above the porary interruption of fresh- by brackish-water or marine fMcElmo formation and beneath the Mancos shale. As conditions. This fPost-McElmo unit was named Burro the fMcElmo is considered, for the most part at least, Canyon formation by Stokes in 1948. to be of Jurassic age and equivalent to the Morrison fMcElmo formation. The upper part is chiefly variegated shale, whereas the lower part is white to greenish-gray sandstone of other regions, and as its uppermost beds are sepa­ that contains the carnotite-bearing beds. Fossil wood, rated from the overlying plant-bearing strata by an poorly preserved twigs, and other plant fragments occur unconformity of unknown extent, and as marine beds throughout the formation. Large reptilian bones occur in of the Mancos shale of Upper Cretaceous age conform­ the basal portion. Coffin designated the fMcElmo as ably overlie the plant-bearing beds, it follows that all Jurassic or Cretaceous. The U. S. Geological Survey of Lower Cretaceous (unless some of the uppermost regards it as Morrison (Jurassic). part of the fMcElmo is Lower Cretaceous in age) and The fPost-McElmo and Dakota of the foregoing sec­ part of Upper Cretaceous time must be represented by tion are the debatable strata whose age is in question. the interval between the fMcElmo and Mancos deposits. Because only plant fossils have been obtained from How much, if any, of this sequence is Lower Cretaceous them, the history of attempts to determine their age and how much is Upper Cretaceous is the problem is that of the treatment of the several collections, as, in posed for solution by a study of the fossil plants. part, already related by Junius Henderson (Coffin, 1921, The best collections of plants have come from south­ pp. 113-118.) Of these collections, the first to be re­ western Colorado, and this area, therefore, will receive ported was made in 1915 by J. T. Duce for the Geological most attention here. A complete description of the Survey of Colorado. This came from the upper sandy tlndicates the name has been abandoned or rejected for use beds of the Dakota and was studied by Cockerell (1916), in classification in Geological Survey publications. who tentatively identified in it the following species 45 46 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1949 (with later emendations suggested by E. W. Berry, in Berry (Coffin, 1921, p. 116) identified the following parentheses) : species in the black shale: Equisetum (=stipe of Matonidium americanum) BracJiyphyllum sp. Matonidium althausi (=Matonidium americanum) Pinus susguaensis Dawson Fragments of other ferns (1=Onychiopsis) Splienolepis Jcurriana (Dunker) Schenk Cycadospadix? (=frond base of Matonidium americanum) Cissites sp. Sapindopsis (= undetermined dicotyledon) Sassafras mudgei Lesquereux Cockerell considered that this assemblage indicated Berry's opinion (Coffin, 1921, p. 117) concerning the Lower Cretaceous age, probably the same as the Fuson age of both collections, that in the upper sandstone and shale in the vicinity of the Black Hills, S. Dak., and that in the black shale, is as follows: somewhat younger than the Kootenai formation of Regarding the age of the material, it is not extensive or good Montana. enough for one to be dogmatic about, but I see nothing to indi­ In 1914 Henderson and others collected plants from cate that either the older shale or the younger sandstone repre­ a black shale horizon south of Nucla, but these were sents the true Dakota. There are no typical Dakota species in either and the general facies appears to me to be slightly not seen or considered by Cockerell at the time he re­ older. Neither would I place either in the Lower Cretaceous, ported the 1915 collection by Duce. They were, how­ hut would be inclined to consider that both floras represent the ever, sent to E. W. Berry early in 1919 along with the same general horizon, and I am strongly of the opinion that this Duce material. Berry (1919) shortly thereafter pub­ horizon is to be correlated with what has been called the Purga- lished a paper dealing with the principal and most toire formation in southeastern Colorado. . . . It is also to be correlated with the Belvidere section of southern Kansas at the striking species in the Duce collection, namely, the top of the Washita division of the Texas Comanchean. The fern Matonidiiim americanum. His opening statement, Washita is commonly considered to represent the top of the unfortunately, is misleading, for it says that "In 1916 Lower Cretaceous, but I am confident that it is Cenomanian in Professor Cockerell, of the University of Colorado, age and represents the lower part of the Upper Cretaceous as I published a brief note based upon plant material col­ stated in my "Upper Cretaceous Floras of the World", and in this I am corroborated by European paleontologists from the lected from the supposed McElmo formation of south­ fauual evidence. western Colorado." Reference to Cockerell's opening paragraph (1916, p. 109), however, shows that Berry Thus the matter stood until 1925, when W. W. Boyer misread the locality citation, which says in part, "Above found fragmentary plants in the Dakota at the Liberty the McElmo, black shales alternate with massive sand­ Bell mine near Naturita, south of Nucla. These were stone, the two combined including the uppermost 131 identified in a routine report, by F. H. Knowlton, as feet of the whole exposure. The plants are preserved including the species: in hard white quartzose sandstone, with occasional iron Cladophlebis falcata montanensis Fontaine concretions about 10 feet below the top of the section." Gleichenia nordenskioldi Heer In this paper Berry did not express a definite opinion as Of the age Knowlton said: "It may be Dakota, but to the age of the collections. Concerning the strati- somehow I cannot escape the conviction that it is older graphic level of the black shale, Henderson said (Coffin, than Dakota." 1921, p. 116) that it was "in a shale lens in the basal In 1944 W. L. Stokes, associated with K. P. Fischer conglomerate of the so-called Dakota, near the top of of the U. S. Geological Survey, obtained an excellent Norwood Hill, where the wagon road from Placerville collection from gray shales in the Dakota at an aban­ to Norwood leaves the San Miguel Canyon." Hender- doned coal mine in SW^SE^ sec. 11, T. 46 N., K. 16 W. In 1945 he found a good specimen of Frenelopsis varians son's use of the term "so-called Dakota" would super­ Fontaine in black shale in the upper part of the f Post- ficially suggest the Dakota of Coffin, but, in reality, the McElmo, one-half mile east-southeast of the junction black shale is in the basal part of the f Post-McElmo as of Disappointment Creek and Dolores River. He also a letter, dated Feb. 1, 1919, from Henderson to Berry found a fragment of a cycadeoid in the basal fPost- indicates: McElmo on the southwest side of Little Gypsum Valley. The material from the black shale, . . . occurred in a lens From sandstone in the Dakota near the black shale lo­ of shale in the basal conglomerate, just above the variegated cality, but about 20 feet higher stratigraphically, he shales of the McElmo, far below the upper sandstone. . . . obtained a collection containing numerous dicotyle­ Since the question of the position of this shale was raised by the discovery of the material in the upper sandstone, Mr. Wor­ donous leaves. Finally, in 1948, he made another ex­ cester, who is a very careful observer, revisited the place, and cellent collection in pinkish-gray shale of the Dakota fully confirms my notes. near the coke ovens at Naturita. This collection con- CRETACEOUS PLANTS FROM SOUTHWESTERN COLORADO 47 tains the same ferns as occur in his original 1944 variegated Morrison (Jurassic) and massive Dakota collection but also includes several well-preserved sandstone (Upper Cretaceous). The age of the dicotyledons. Purgatoire was determined as Comanche (Lower The best material of each recognizable species in all Cretaceous) by Stanton on the evidence of character­ these collections, now available to me, is here illustrated istic marine invertebrates and fishes. Gryphaea cor- and described, and an attempt is made to integrate all rugata, in particular, was said to indicate equivalence the information into a satisfactory picture of the entire of at least part of these beds with the Kiowa shale of situation. Kansas. No plants have been taken from the type area of the Purgatoire formation, but some poorly preserved AGE AND SIGNIFICANCE OF THE FOSSIL PLANTS leaves were collected by W. T. Lee in beds so designated The fossil plants here described fall into two groups. by him at the type section of the Morrison formation The first includes Cycadeoidea sp. (pi. 9, fig. 13), near Morrison, Colo. These plants were identified Brachyphyllum crassicaule Fontaine (pi. 9, figs. 5, 6), by F. H. Knowlton and restudied by E. W. Berry Frenelopsis varians Fontaine (pi. 9, fig. 12), Spheno- (Brown, 1946, p. 240), with rather inconclusive results, Upis hurriana (Dunker) Schenk (pi. 9, fig. 14), and except that the flora resembles that from the Cheyenne a few undetermined specimens (pi. 9, figs. 8-11). sandstone of Kansas. The second group contains all the remaining speci­ The only forms in common between the fPost- mens, including numerous ferns and well-developed McElmo and the Kootenai formation of Montana are dicotyledons. Sphenolepis kwriana (Dunker) Schenk and the prob­ Three of the specifically identified species of the first lematic Finite susquaensis Dawson. group, but particularly Frenelopsis varians, are charac­ An interesting situation has arisen in regard to the teristic Lower Cretaceous forms. Cycadeoidea falls Potomac group of the Atlantic Coastal Plain, which readily into this picture. Frenelopsis varians, how­ has long been regarded as Lower Cretaceous. In the ever, is the clue to the age of this group, as it has never volume, edited by Anderson (1948, pp 126-151), on been found in younger strata. All the specimens in the subsurface geology in three deep wells, H. E. Vokes this group occur in the fPost-McElmo of Coffin (p. 3) discusses the Mollusca found at depths 4,875 to 4,885 in and beneath the conglomeratic sandstone of the Dakota, the Maryland Esso No. 1 well, 4^ miles north of above which all the plants of the second group were Ocean City, Md. Vokes inclines to the belief that the collected. Patuxent formation is Lower Cretaceous and the The plants of the second group include chieflly species Arundel and Patapsco formations are earliest Upper that occur in the large flora described by Lesquereux, Cretaceous, for he finds that the Mollusca of the two Newberry, and others from the brownish Dakota sand­ latter formations have their closest affinities with those stone of Kansas and Nebraska, in the Woodbine forma­ of the Woodbine formation (Upper Cretaceous) of tion of Texas, the Dakota of the Black Hills, S. Dak., Texas. This conclusion appears to be fortified by C. and the Upper Cretaceous rocks of Greenland. A few W. Gilmore's opinion that the dinosaurs of the Arundel species were probably closely related to some in the formation have closest affinities with those of the Belly Patapsco formation of the Potomac group in the Atlan­ River formation (Upper Cretaceous) in Canada. The tic Coastal Plain. great development of dicotyledons in Patapsco time, In view of these facts I conclude that in southwestern and especially of species similar to, if not identical with, Colorado the fPost-McElmo is Lower Cretaceous and some in the Dakota sandstone and other Upper Creta­ the Dakota of Coffin is Upper Cretaceous. I would ceous formations of the western interior, lends consider­ draw the boundary line at the bottom of the conglom­ able weight to the view that the Patapsco, at least, eratic sandstone at the base of Coffin's Dakota. should be removed from the Lower Cretaceous The scarcity of well-preserved plants in the Lower classification. Cretaceous section in southwestern Colorado is matched Not much can be inferred from the fossil plants con­ by a similar condition east of the Eocky Mountains in the vicinity of Morrison and Walsenburg, Colo. Stose cerning the climate and environment of southwestern (1912, p. 3) described the typical Purgatoire formation Colorado during Lower Cretaceous and early Upper in the Apishapa quadrangle east of Walsenburg, Colo., Cretaceous time. The probability is that the region as including 220 feet of beds, chiefly sandstone in the was low lying and not far above sea level. Frenelopsis basal portion and coal, shale, and sandstone in the varians, as judged by its occurrence in the Trinity upper portion, the whole lying conformably between group of Texas where it is found with marine inverte- 48 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1949 brates, preferred a coastal environment. Cycadeoidea who resurrected the Paleozoic name Gleichenites for the may indicate a somewhat drier location on a hillside. few species to which he reduced the many described by The early Lower Cretaceous sediments in this area Heer. were deposited near sea level, because at one locality As the specimens under consideration here bear no Halymenites has been found. The ferns Matonidium sori, they can be compared but probably not identified and Bolbitis, if judged by their modern relatives in the satisfactorily with any described species. They re­ Malay region, would indicate a relatively warm and semble closely some specimens of Gleichenites giese- moist environment at the beginning of the Upper kiana (Heer) Seward, .as synonymized by Seward Cretaceous. These ferns, however, were found in the (1926, p. 69). They are somewhat like Gleichenia ar- shales associated with coal beds and reflect a swampy gentinica Berry (1924, p. 17). However, no matter condition. The dicotyledons, on the other hand, indi­ how these comparisons may be evaluated, the species cate drier situations probably not far from the coal- is very likely that identified as Gleichenia kurriana forming swamps. Heer by Lesquereux from the Dakota sandstone, 3 miles east of Fort Harker (now Kanopolis), Kans. Lesque­ SYSTEMATIC DESCRIPTIONS reux was uncertain that the Dakota species is identical ASPLENIACEAE with G. kurriana from Europe. That the Gleichenia represented by the Colorado Asplenium sp. specimens has a long chronological range is likely, for Plate 10, figure 4 Heer's Lower Cretaceous species seem to range locally Asplenium, dicksonianum Heer. Ward, U. S. Geol. Survey 19th also into the Upper Cretaceous. Ann. Kept., pt. 2, p. 704, pi. 170, fig. 1,1899. A small fragment of what appears to be this species The specimen figured here appears to agree in every was collected by Karl Waage in 1943 from a white sand­ respect with that reported by Ward from the basal beds stone in the Dakota near Stone City, 15 miles north­ of the Dakota sandstone in Evans quarry, 5 miles west of Pueblo, Colo. southeast of Hot Springs, S. Dak. This fern was evi­ Occurrence: One and one-half miles southwest of dently bipinnate, with the pinnules in some instances coke ovens, Montrose County, Colo. Collected by W. L. deeply cut. These lobes have entire margins. The Stokes, 1948. venation is open and once or twice forked. No fertile MATONIACEAE fronds have been seen.. Matonidium americanum Berry It does not seem to me that either the present speci­ Plate 10, figures 7, 8 men or Ward's specimen from the Black Hills should be referred to Heer's Asplenium dicksonianum, which, Matonidium americanum Berry, Torrey Bot. Club Bull., vol. 46, p. 287, fig. 2; pi. 12, figs. 1-12; pi. 13, figs. 3-6, 1919. according to the figured type and other supplementary Matonidium althausi (Dunker) Ward. Cockerell, Washington specimens, is a smaller, more delicate fern, although Acad. Sci. Jour., vol. 6, p. Ill, fig. 2,1916. perhaps of the same genus. There is doubtless con­ Cycadospadix? sp. Cockerell, idem, p. 110, fig. 1. fusion in regard to the generic assignment, as somewhat This species was as well described by Berry as was similar or perhaps identical material has been referred possible with the fossil material at his disposal. To to Onychiopsis, Aneimia, and other genera. I know of that description need be added perhaps only a few minor no method to resolve this difficulty until adequate fertile details. The venation of the fertile pinnules is obscure, material is found. but that of the sterile pinnules is as shown in figure 7. Occurrence: Abandoned coal mine near Naturita, 4 The secondary veins may be simple, branched, with a miles south of Nucla, Colo. Collected by W. L. Stokes, few scattered anastomoses, the principal forming lateral 1944. areolations along the midribs. GLEICHENIACEAE The features that distinguish this species from the Gleichenia kurriana Heer Lower Cretaceous Matonidium althausi (Dunker) Ward are: more numerous pinnae, shorter and broader Plate 10, figures 5, 6 pinnules, fewer sori, and more conspicuously scorpioid Gleichenia kurriana Heer. Lesquereux, U. S. Geol. Survey Terr. disposition of the pinnae at the top of the stipe. As no Kept., vol. 6, p. 47, pi. 1, figs. 5, 5b, 5c, 1874. exactly identical material has been described before, the Many species of Cretaceous gleichenias have been de­ presumption is that M. americanum represents an ad­ scribed, especially by Oswald Heer from Greenland. vance on M. althausi. This inference is strengthened The Greenland species were reviewed by A. C. Seward, by the fact that in the present material are fragments, CRETACEOUS PLANTS FROM SOUTHWESTERN COLORADO 49 such as relatively long, slender pinnules completely Occurrence: At the abandoned coal mine near covered with sori, that suggest throwbacks to M. Naturita, Colo. althausi. PTERIDACEAE An Upper Cretaceous species comparable to Matoni- Llavea hesperia Brown, n. sp. dium americanum is Matonia wiesneri Krasser (1896, p. 119, pi. 11, fig. al; pi. 12, figs. 1, 2; pi. 17, fig. 10) Plate 11, figure 6 from Cenomanian beds near Kunstadt, Austria. This somewhat eroded sterile leaf is nevertheless well Krasser's illustrations, showing the habit of the species, enough preserved to indicate its original cordate out­ suggest a peltate arrangement of pinnae around the line. The veins are open, closely spaced, and repeatedly apex of the stipe, but I suspect that the drawings per­ forked. The margin is minutely dentate. haps do not represent the specimens adequately on this At least three living species of ferns may be con­ point and that the pinnae are actually disposed in a sidered for comparisons with the fossil. Humata rather close scorpioid fashion fanwise, as stated in ophioglossoides Cavanilles, a davallioid fern from the Krasser's description. According to Krasser's figures, Malay-Polynesian region, is an epiphyte with simple, the venation of the pinnules is without anastomoses or lanceolate-cordate, sterile fronds that are about the areolations. Such fruiting specimens as Krasser found same size as the fossil. The veins, however, are thicker had few sori per pinnule. Despite these close simi­ and less forked. Pellaea cardiomorpha Weatherby, larities, I am disinclined to recognize the two species from Mexico, is a pinnate pteridoid fern with cordate as identical. pinnules closely simulating the fossil. It, however, Matonidiwn americankm resembled the graceful, ex­ prefers relatively dry, rocky situations, whereas the isting Matonia pectinata Robert Brown, of southeastern fossil, judging from its associates, lived in a moister Asia and the East Indies. This species has a creeping habitat. Llavea cordifolia Lagasca, a monotypic rhizome that produces at distant intervals simple, un- pteridoid fern from central Mexico to Guatemala and branched fronds composed of a tall, upright stipe, the distantly related to Pellaea cardiomorpha, has cordate apex of which widens into a semicircular base or crown, pinnules and seems to compare best of all with the giving rise dichotomously to the scorpioidly disposed fossil. The assignment of the fossil to Llavea must pinnae, which spread out horizontally, that is, at right be considered tentative until a fertile pinnule or other angles to the stipe. confirmatory material is found. Occurrence: At abandoned coal mine near Naturita, For making available material of living ferns and 4 miles south of Nucla, and at coke ovens, Montrose for helpful consultation toward identification, I am County, Colo. Collected by W. L. Stokes. grateful to C. V. Morton, curator of ferns in the U. S. National Herbarium, Smithsonian Institution. POLYPODIACEAE Occurrence: One and one-half miles southwest of Bolbitis coloradica Brown, n. sp. coke ovens, Montrose County, Colo. Plate 12, figures 6,. 7 TEMPSKYACEAE Sterile frond pinnate below, but with segments tend­ Tempskya knowltoni Seward ing to coalesce into a lobed blade toward the apex. Margin entire. Basal pinnae linear lanceolate, sessile Plate 9, figure 15 or nearly so, with slightly asymmetric rounded bases. Tempskya Icnowltoni Seward, Annals of Botany, vol. 38, pp. Secondary veins numerous, closely spaced, slightly 485-507, pis. 16, 17, 1924; Brown, Washington Acad. Sci. curved, almost at right angles to the midrib, simple un­ Jour., vol. 26, pp. 46, 47, fig. 5, 1936; Read and Brown, U. S. Geol. Survey Prof. Paper 186, pp. 112-114, pi. 29, figs. 1-3, til near the margin, where they may fork or branch. 1937. Areoles between the secondary veins somewhat rhom- This piece of a trunk of Tempskya measures 4 by 6 boidal and elongated parallel to the secondaries. Fertile fronds not present in the collection. cm. It contains a few sections of stems surrounded Comparison of these fossils with living ferns reveals by roots. The stems are relatively small like those of closest resemblance to the entire-margined species of Tempskya knowltoni Seward from the Upper Creta­ Bolbitis, formerly variously called Campiwm, Poecil- ceous of Montana. opteris, Heteronewron, and others. The genus com­ Occurrence: SW% sec. 28, T. 22 S., R. 22 E., Utah. prises about 85 species, distributed in the tropics, In lower part of Dakota?, 100 feet above the Morrison particularly of Africa and the Indo-Malayan region. formation. Collected by W, L. Stokes, 1944. 868180 50 2 50 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1949 CYCADACEAE Patuxent formation of the Potomac group at Trents Cycadeoidea sp. Reach, Va. The latter, however, displays a little leaf development at the nodes. Plate 9, figure 13 As Frenelopsis varians and its closest relatives have This fragment of a cycadeoid trunk, showing part of never been found in other than Lower Cretaceous strata, a fruit and numerous leaf bases or traces, is too poorly I am inclined to regard it as a Lower Cretaceous time preserved for specific identification. index. Occurrence: In the basal part of the fPost-McElmo Occurrence: Black shale in upper part of fPost- beds, not far above the unconformity with the fMcElmo. McElmo but beneath basal sandstone of the Dakota. Southwest side of Little Gypsum Valley, San Miguel Collected by W. L. Stokes, 1945. County, Colo. Collected by W. L. Stokes, 1946. Sphenolepis kurriana (Dunker) Schenk CONIFERALES Plate 9, figure 14 Brachyphyllum crassicaule Fontaine Sphenolepis kurriana (Dunker) Schenk. Berry, Maryland Plate 9, figures 5, 6 Geol. Survey, Lower Cretaceous, p. 432, pi. 74, figs. 2, 3,1911. See extensive synonymy. Brachyphyllum cr.assicaule Fontaine, U. S. Geol. Survey Mon. 15, p. 221, pi. 100, fig. 4; pi. 109, figs. 1-7; pi. 110, figs. 1-3; This many-named conifer, or a very closely related pi. Ill, figs. 6, 7; pi. 112, figs. 6-8; pi. 158, fig. 9, 1889. species, is common in Lower Cretaceous strata in Vir­ A number of Lower and Upper Cretaceous species of ginia, South Dakota, Montana, and California. With­ the conifer B rockyphyllum have been described, but out attached fruits the species of /Sphenolepis are not methods for clearly distinguishing them, especially readily distinguishable from one another. when possible variations in individual trees and parts Occurrence: In black shale in lower part of fPost- of trees are taken into account, have not been stated. McEhno, south of Nucla, Colo. Collected by Junius The situation has been reviewed by Berry (1911, p. 389). Henderson and party, 1914. The specimens in this collection are poorly preserved JUGIAWDACEAE in respect to details, although in places enough of the Juglans crassipes Heer spirally arranged, closely appressed leaves can be seen to permit reconstruction as shown in the illustrations. Plate 12, figures 8, 9 Assignment to Brachyphyllum, crassicaule Fontaine Juglans crassipes Heer. Lesquereux, U. S. Geol. Survey Mon. seems reasonable, although B. macrocarpum Newberry 17, p. 69, pi. 49, figs. 1-3, 1892. and B. parceramosum Fontaine are also very similar. These specimens from southwestern Colorado seem The latter is a common Lower Cretaceous species, in­ to fall readily into this classification, but doubt must be cluding, according to Berry, B. texense Fontaine, from entertained concerning the reference of the species to the Glen Rose limestone of the Trinity group in Texas. Juglans. Figure 5 apparently represents the termination of a Occurrence: One and one-half miles southwest of twig or a fruiting organ with elongated leaves or bracts. coke ovens, Montrose County, Colo. Occurrence: In black shale in lower part of fPost- McElmo, south of Nucla, Colo. Collected by Junius MORACEAE Henderson and party, 1914> Ficus daphnogenoides (Heer) Berry

Frenelopsis varians Fontaine Plate 11, figures 1, 2, 5 Plate 9, figure 12 Proteoides daphnogenoides Heer. Lesquereux, U. S. Geol. Survey Terr. Kept, vol. 6, p. 85, pi. 15, figs. 1, 2, 1874. Frenelopsis varians Fontaine, U. S. Nat. Mus. Proc., vol. 16, Ficus daphnogenoides (Heer) Berry, Torrey Bot. Club Bull., p. 273, pi. 40, figs. 1, 2; pi. 41, figs. l-3a, 1893. vol. 32, p. 329, pi. 21, 1905; Berry, U. S. Geol. Survey Prof. This coniferous fragment is characteristic of the Paper 129, p. 163, pi. 39, fig. 1, 1922. See synonymy. species, showing little or no development of leaves at These entire-margined leaves have been referred to the nodes, the twigs having served the function of many different genera with little satisfaction, as might leaves. The parallel rows of dots represent stomata. be expected for entire leaves, the internal venational The species was described from the Trinity group structure of which tends in many toward similarity. I (Lower Cretaceous) on the .Paluxy River, near Glen regard the reference to Ficus as a makeshift. Many Rose, Texas. It resembles most closely Frenelopsis similar leaves from the Dakota sandstone have been parceramosa Fontaine (1889, p. 218) found in the referred with little evidence to Andromeda. All are CRETACEOUS PLANTS FROM SOUTHWESTERN COLORADO 51 perhaps examples of lauifaceous species that are difficult Platanus, Sterculia, or to some other genus is untimely to separate. At any rate, they are fairly abundant in and of no advantage so far as stratigraphy is concerned. early Upper Cretaceous strata. Occurrence: Near junction of Disappointment Creek Occurrence: Near junction of Disappointment Creek and Dolores River, San Miguel County, Colo. and Dolores River, San Miguel County, Colo. Collected by W. L. Stokes, 1945. PLATANACEAE Platanus newberryana Heer NYMPHAEACEAE Plate 12, figure 3 Nelumbium sp. Platanus newberryana Heer. Lesquereux, TJ. S. Geol. Survey Plate 10, figure 2 Terr. Kept., vol. 6, p! 72, pi. 8, figs. 2, 3; pi. 9, fig. 3, 1874. This fragment, with a portion of the entire margin The fragment figured here is the tip of the middle and a number of the radial veins preserved, has the lobe of a leaf of this species. The scalloped sinuses be­ characteristic features of a waterlily leaf. It, however, tween the teeth and the disposition of the secondary is so imperfect that a specific designation does not seem veins and their branches into the teeth are character­ warranted. istic features. No waterlily has thus far been identified from Lower Occurrence: One and one-half miles southwest of Cretaceous strata in the western states, but species coke ovens, Montrose County, Colo. appear in early Upper Cretaceous deposits. Occurrence: One and one-half miles southwest of coke CELASTRACEAE ovens, Montrose County, Colo. Celastrophyllum stokesi Brown, n. sp.

BERBERIDACEAE Plate 12, figures 1, 2 Mahonia furnaria Brown, n. sp. Lanceolate leaves, with rounded, crenate-dentate marginal teeth. Midrib strong. Secondary veins and Plate 12, figure 4 intersecondaries form an anastomosing, more of less Compound leaf with five lanceolate leaflets, the looped, network with short branches into the teeth. laterals being sessile, the terminal long-petioled. This species approaches closely to G elastropfiyllimi Margins serrate, with sharp teeth. Sinuses between ensifolium Lesquereux (1874, p. 108, pi. 21, figs. 2, 3) the teeth scalloped. The secondary venation makes from near Fort Harker, Kans., but the leaves of the conspicuous internal, closed areas, with anastomoses latter, especially Lesquereux's figure 2, are elliptic and with thin branches to the teeth. rather than lanceolate and the teeth are shorter and All the features of this leaf seem to ally it clearly sharper. Berry (1911, pp. 474-481) recognized seven with the genus Mahonia in the barberry family. If so, species of C elastrophyllum in the Patapsco formation, it may be in the ancestral line of the numerous species the species most closely resembling C. stokesi being per­ described from Eocene, Oligocene, and Miocene strata haps G. acutidens Fontaine (Berry, 1911, p. 478, pi. 89), in the northwestern states. a specimen of which Ward had tentatively labeled G. Occurrence: One and one-half miles southwest of coke pulcfirum. He, however, did not publish the name un­ ovens, Montrose County, Colo. til later (1899, p. 706, pi. 171, figs. 3, 4) in connection with what he considered identical material from the LAURACEAE Dakota of the Black Hills. G. stokesi may be the same Sassafras cretaceum Newberry as G. acutidens, but the leaves of the latter appear to be Plate 11, figure 8 shorter and more elliptic. It is significant that, as Berry (1911, p. 475) pointed out, GelastrophyllMm is Sassafras cretacewn Newberry, TJ. S. Geol. Survey Mon. 35, p. 98, pi. 6, figs. 1-4; pi. 7, figs. 1-3; pi. 8, figs. 1, 2, 1898. not present in the Patuxent and Arundel formations of The blunt, rounded lobes, as well as the venation of the Potomac group. Neither is it present in any other this specimen, conform closely to those of Newberry's formations attributed to the Lower Cretaceous. Con­ plate 8, figure 1, and to several figured by Lesquereux sequently, this may be additional evidence for consider­ as /Sassafras cretacewn var. obtu&wn, and S. obtusum ing the Patapsco formation as Upper Cretaceous in age. from the Dakota sandstone of Kansas and Nebraska. Occurrence: One and one-half miles southwest of The reference of these leaves to Sassafras is question­ coke ovens, Montrose County, Colo. Collected by W. L. able, but transfer to Ardlia, Araliopsis, Araliopsoides, Stokes, 1948, for whom the species is named. 52 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1949

STERCULIACEAE taceous it would not be surprising to find reversions or Sterculia towneri (Lesquereux) Berry throwbacks to such leaves in Upper Cretaceous col­ lections. Plate 9, fig. 7; plate 11, figs. 3, 4 On this basis, the lobed leaves of the Lower Creta­ Sterculia, towneri (Lesquereux) Berry, U. S. Geol. Survey Prof. ceous Cheyenne sandstone, assigned by Berry to Ster­ Paper 129, p. 217, 1922. See synonymy and cited figures. culia towneri, ought perhaps to be given a new name, These lobed Cretaceous leaves arouse considerable whereas those of the Upper Cretaceous Dakota sand­ speculation as to separation of species and assignment stone remain S. towneri. The reassignment of some or to a definite botanical category. Berry's synonymy in­ all of these leaves to another genus than Sterculia must cludes leaves from both Lower and Upper Cretaceous some day be considered. zones, and, therefore, if correct, the species cannot serve Occurrence: Near'junction of Disappointment Creek for distinguishing one zone from the other. Doubts, and Dolores River, San Miguel County, Colo. however, may well be expressed about the Berry synon­ Capsulocarpus dakotensis Berry ymy, after examining numerous leaves from both zones. Berry included under Sterculia towneri only lobed Plate 9, figure 3 leaves with entire margins. A critical feature of the Capsulocarpus dakotensis Berry, Washington Acad. Sci. Jour., venation of these leaves must also be noted, namely, that vol. 29, pp. 331-336, figs. 1-4, 1939. the branching of primary veins from the midrib oc­ The fruit here figured is considerably smaller than curs at some distance above the top of the petiole and those reported by Berry from the Dakota sandstone actual base of the blade. If the leaf is five-lobed, the near New Ulm, Minn., but resembles them in all other lateral primaries fork at 1 or 2 cm. from the midrib. respects general outline, transverse plications, and Thus the venational architecture is strikingly like that marginal flange. As shown by Berry's figure 2 of the of Platanus. This pattern is also seen in the lobed counterpart of his figure 1, the specimens with the Cretaceous leaves assigned by Lesquereux to various flanges and transverse folds are casts of the interiors species of Aralia, Cissites, Liquidambar, and Sassafras. of fruits. The lobes of the Aralia species, however, have more or The relationship of this fruit is unknown. Except less toothed margins, with scalloped sinuses between the for the prominent flange, there is some resemblance to sharp teeth, thus especially simulating leaves of Pla­ the fossil fruits of Cercidiphyllum, some of which are tanus. The association of similar, entire-margined relatively large as compared with the fruits of the liv­ with toothed-margined, lobed leaves that have been as­ ing species. signed to the same species in Paleocene, Eocene, and Occurrence: Near junction of Disappointment Creek Oligocene strata in the northwestern states suggests a and Dolores River, San Miguel County, Colo. need for further study of the Cretaceous species here discussed and of Berry's Sterculia towneri synonymy. SPECIMENS OF UNCERTAIN IDENTITY Be all this as it may, the prime question so far as Plate 9, figure 1. This is part of a spherical fruit dating is concerned is whether any differences can be head with many closely packed, squarish carpels radi­ detected in these leaves that will permit separation of ating from a round center. It may represent an early Lower and Upper Cretaceous strata. Unfortunately, burreed, Sparganiwn. Disappointment Creek. too few of these leaves (except in the Cheyenne sand­ Plate 9, figure 2. This is a reticulately pitted seed stone where they are not very well preserved), have that probably belongs with the fruit, plate 9, figure 1. been found in known Lower Cretaceous strata, thus Disappointment Creek. giving perhaps an imperfect idea of their features. Plate 9, figure 4. This may be the young stage of the However, I find that the known Upper Cretaceous fruit in plate 9, figure 1. Disappointment Creek. leaves are more deeply lobed, with a greater tendency to Plate 9, figure 8. A lobed leaf, perhaps of a species being toothed and with lobes that tend to be wider of Sassafras. Black shale near base of fPost-McElmo. medianly. The Lower Cretaceous leaves are less deeply Plate 9, figure 9. Perhaps a fragment of a cycad lobed, with scarcely any toothing, and the lobes tend leaf. Black shale near base of fPost-McElmo. to be cuneate, with scarcely any median widening. Plate 9, figures 10,11. These are the narrow needle- It will be noted that the leaves here figured display like specimens identified by Berry as Pinus susguaensis the features noted for the Upper Cretaceous leaves. Dawson. Such material also occurs in the Kootenai If, as seems most likely, the Lower Cretaceous leaves formation of Montana and in other Lower Cretaceous are immediately ancestral to those in the Upper Cre­ strata in the United States and Canada. However, the CRETACEOUS PLANTS FROM SOUTHWESTERN COLORADO 53 "needles" have never been seen in fascicles, nor have Berry, E. W., 1924. Mesozoic Gleichenia from Argentina: Pan- authentic pine seeds been found with them, and con­ Am. Geologist, vol. 41, pp. 17-21. sequently the identification as Pinus remains uncon­ 1939. Fossil plants from the Cretaceous of Minnesota: Washington Acad. Sci. Jour., vol. 29, pp. 331-336. firmed. Black shale near base of fPost-McElmo. Brown, R. W., 1946'. Fossil plants and Jurassic-Cretaceous Plate 10, figure 1. A dicotyledonous leaf with un­ boundary in Montana and Alberta: Am. Assoc. Petroleum usually coarse, serrate teeth. One and one-half miles Geologists Bull., vol. 30, pp. 238-248. southwest of coke ovens. Cockerell, T. D. A., 1916. A Lower Cretaceous flora in Colorado: Plate 10, figure 3. An undetermined fern. Four Washington Acad. Sci. Jour., vol. 6, pp. 109-112. Coffin, R. C., 1921. Radium, uranium, and vanadium deposits miles south of Nucla. of southwestern Colorado: Colorado Geol. Survey Bull. 16. Plate 11, figure 7. Apparently a fruit or husk of a 1924. Some anticlines of western Colorado: Colorado fruit. Disappointment Creek. Geol. Survey Bull. 24, pp. 1-68. Plate 12, figure 5. A flower with 3 broad-based, Fontaine, W. M., 1889. The Potomac or younger Mesozoic alternating with 3 narrow-based oblanceolate petals or flora: U. S. Geol. Survey Mon. 15. 1893. Notes on some fossil plants from the Trinity sepals. In the center are 3 striated seeds. This struc­ division of the Comanche series of Texas: U. S. Nat. Mus. ture may represent a monocotyledon. One and one- Proc., vol. 16, pp. 261-282. half miles southwest of coke ovens. Krasser, Fridolin, 1896. Beitrage zur Kenntniss der fossilen Kreideflora von Kunstadt in Mahren: Beitr. Palaontologie BIBLIOGRAPHY und Geologic 5 sterr.-Ungarns, Band 10, Heft. 3, pp. 15-152. Anderson, J. L., and others, 1948. Cretaceous and Tertiary Lesquereux, Leo, 1874. The Cretaceous flora: U. S. Geol. Survey subsurface geology: The stratigraphy, paleontology, and Terr. Rept, vol 6. sedimentology of three deep test wells on the Eastern Shore Seward, A. C., 1926. The Cretaceous plant-bearing rocks of of Maryland: Maryland Dept. Geology, Mines, and Water western Greenland: Royal Soc. London Philos. Trans., ser. Resources, Bull. 2. B., vol. 215, pp. 57-175. Berry, E. W., 1911. Lower Cretaceous flora of Maryland: Stokes, W. L., 1944. Morrison and related deposits in and ad­ Maryland Geol. Survey, Lower Cretaceous, pp. 214-508. jacent to the Colorado Plateau: Geol. Soc. America Bull., 1919. A new Matonidium from Colorado, with remarks vol. 55, pp. 951-992. on the distribution of the Matoniaceae: Torrey Bot. Club 1948. Geology of the Egnar-Gypsum Valley area, San Bull., vol. 46, pp. 285-294. Miguel and Montrose Counties, Colorado: U. S. Geol. Survey 1920. The age of the Dakota flora: Am. Jour. Sci., vol. Oil and Gas Investigations Prelim. Map 93. 50, pp. 387-390. Stose, G. W., 1912. U. S. Geol. Survey Geologic Atlas, Apishapa 1922a. The flora of the Woodbine sand at Arthurs Bluff, folio (no. 186). Texas: U. S. Geol. Survey Prof. Paper 129, pp. 153-181. Ward, L. F., 1899. The Cretaceous formation of the Black Hills 1922b. The flora of the Cheyenne sandstone of Kansas: as indicated by the fossil plants: U. S. Geol. Survey 19th U. S. Geol. Survey Prof. Paper 129, pp. 199-225. Ann. Rept., pt. 2, pp. 527-712.

PLATES 9-12

55 PLATE 9

Figure 1. Undetermined fruit with squarish carpels. X 2. 2. Undetermined pitted seed. X 8. 3. Capsulocarpus dakotensis Berry x 2. 4. Undetermined fruit. 5. 6. Brachyphyllum crassicaule Fontaine. 7. StercuUa towneri (Lesquereux) Berry. 8. Probably a species of Sassafras. 9. Probably a fragment of a cycad leaf. 10,11. Probably Pinus susquaensis Dawson. 12. Frenelopsis varians Fontaine. 13. Cycadeoidea sp. 14. Sphenolepis kurriana (Dunker) Schenk. 15. Tempskya knowltoni Seward. GEOLOGICAL SURVEY PBO:FESSIONAL PAPER 221 PLATE 9

CRETACEOUS PLANTS PLATE 10

Figure 1. Undetermined dicotyledonous leaf. 2. NelumMum sp. 3. Undetermined fern. 4. Asplenium sp. 5,6. Gleiclienia Jcurriana Heer. 7, 8. Matonidium americanum Berry. GEOLOGICAL SUEVEY PKOFESSIONAL PAPER 221 PLATE 10

CRETACEOUS PLANTS PLATE 11 Figures 1, 2, 5. Ficus daphnogenoides (Heer) Berry. 3,4. StercwUa towneri (Lesquereux) Berry. 6. Llavea hesperia Brown, n. sp. 7. Undetermined fruit. 8. Sassafras cretaceum Newberry. GEOLOGICAL STTBVEY PKOFESSIONAL PAPEE 221 PLATE 11

CRETACEOUS PLANTS PLATE 12

Figures 1, 2. Celastrophyllum stolcesi Brown, n. sp. 3. Platanus newberryana Heer. 4. Mahonia furnaria Brown, n. sp. 5. Undetermined flower. 6. 7. Bolbitis coloradica Brown, n. sp. 8, 9. Juglans crassipes Heer. GEOLOGICAL SURVEY PBOPESSIONAL PAPER 221 PLATE 12

CRETACEOUS PLANTS

INDEX

Page Page acutidens, CelastrophyUum... ______. 51 giesekiana, Glsichenites. Age of fossil plants ______47-48 Gleichenia...... althausi, Matonidium...... 46,48 argentinica ...... 48 americanum, Matonidium______46, 48-49, pi. 10 kurriana.. ______48, pi. 10 Andromeda...... 50 nordenskioldi....______46 Aneimia...... ______48 Gleichenites...... 48 Ardlia...... ______...... ____._.___...._____ 51,52 giesekiana.^...... 48 AraliopsiS-...... ______51 Gryphaea corrugata...... 47 Araliopsoides...... _..______51 newberryi...... _____ 45 argentinica, Gleichenia...... 48 Asplenium dicksonianum...... 48 Halymenites. _ 45,48 sp.-__-______48, pi. 10 Henderson, Junius, quoted.___.______46 hesperia, Llavea...... ______49, pi. 11 Berry, E. W., quoted______46 Heteroneuron...... _ __ 49 Bibliography______53 Humata ophioglossoides...... _ 49 Bolbitis...... ______.______...- .____.______.._ 48 coloradica______49, pi. 12 Juglans...... ___ 50 Brachyphyttum...... 50 crassipes.. ______50, pi. 12 crassicaule...... _.______47,50, pi. 9 knowUoni, Tempskya.....-.______49, pi. 9 macrocarpum______50 kurriana, Gleichenia______48, pi. 10 parceramosum ______50 Sphenolepis^______46, 47, 50, pi. 9 sp..______46 texense...... 50 Liquidambar______-__._ _ 52 Llavea...... ______49 Campium...... ^...... 49 cordifolia.______-______49 Capsulocarpus dakotensis______52, pi. 9 ia-...... - . _ . 49, pi. 11 cardiomorpha, Pettaea...... 49 Celastrophyttum...... 51 McElmo formation, section near Nucla, Colo... ___ 45 acutidens...... ______.__.______51 macrocarpum, Brachyphyttum...... __ 50 ensifolium...... =.______51 Mahonia...... _ __ 51 pulchrum______51 furnaria...... __ 51, pi. 12 stokesi...... 51, pi. 12 Mancos shale, in section near Nucla, Colo....._ _ 45 Certidiphyllum..--...... ______52 Matonidium...... _ 48 Cissites...... -___ _-...... __....___._____ 46,52 althausi.______46,48 Cladophlebis falcata montanensis______46 americanum..'______- 46, 48-49, pi. 10 Cockerell, T. D. A., quoted...______46 Matonia pectinata...... ___ 49 coloradica, Bolbitis...... 49, pi. 12 wiesneri.... ______. 49 Colorado, fossil collections from______45-47 montanensis, Cladophlebis falcata______46 Disappointment Creek, fossils from______52 mudgei, Sassafras...... ______46 Little Gypsum Valley, fossils from______46,50 Morrison, fossils from______47 Nelumbium sp______- 51, pi, 10 Naturita, fossils from.______..._____ 46,48,49 newberryana, Platanus______.____ . 51, pi. 12 Nucla, fossils from.______45,46,50 newberryi, Gryphaea...... _ _ 45 Stone City, fossils from______'______48 nordenskioldi, Gleichenia______.______46 cordifolia, Llavea....______49 obtusum, Sassafras...... _ 51 corrugata, Oryphaea...... __ .______47 Sassafras cretaceum...... 51 crassicaule, Brachyphyttum...... 47,50, pi. 9 Onychiopsis...... __ 46,48 crassipes, Juglans...... ______50, pi. 12 ophioglossoides, Humata...... __ 49 cretaceum, Sassafras.^...... 51, pi. 11 obtusum, Sassafras...... ______51 parceramosum, Brachyphyttum 50 Cycadeoiidea...... 48 parceramosa, Frenelopsis...... 50 sp. _ ..._ ...___.______47, 50, pi. 9 pectinata, Matonia______- _ 49 Cycadospadix...... ______46,48 Pettaea cardiomorpha______._ ..__ _ 49 Pinus-...... 53, pi. 9 Dakota sandstone, section near Nucla, Colo.. ______45 susquaensis______-______46, 47, 52-53, pi. 9 dakotensis, Capsulocarpus...... 52, pi. 9 Platanus______51,52 daphnogenoides, Ficus...... ___ 50-51, pi. 11 newberryana______- 51, pi. 12 Proteoides______50 Poecilopteris______49 dicksonianum, Asplenium...... ______.___.______48 Post-McElmo, section near Nucla, Colo______45 Previous investigations______45-47 ensifolium, CelastrophyUum...... 51 Proteoides daphnogenoides..___ .___ 50 Equisetum...... ______46 pulchrum, Celastrophyttum______.______. -_ 51 falcata montanensis, Cladophlebis...... 46 Sapindopsis______-______46 Ficus______50 Sassafras...... -...... 51, 52, pi. 9 daphnogenoides...... 50-51, pi. 11 cretaceum. ______51, pi. 11 Frettelopsis parceramosa...... 50 cretaceum obtusum______._...______51 varians...... 45, 47, 50, pi. 9 obtusum______51 furnaria, Mahonia______51, pi. 12 mudgei.. ______46 65 66 INDEX

Page Page Section near Nucla, Colo.. ______45 Tempskya.. ______.. 49 Significance of the fossil plants ______47-48 knowUmi... ______-_____-____.______- 49, pis. 9 Sparganium ______52, pi. 9 lexeme, Brachyphyllum.------___ 50 Sphenolepis ______- ______50 towneri, Sterculia. ______-____-____ 52, pis. 9,11 kurriana 46, 47, 50, pi. 9 ___ __ .... 51,52 Utah, fossil collections from. 49 towneri... ______. ______52, pis. 9, 11 stoked, Celastrophyllum ______. ____ . ____ 51, pi. 12 varians, Frenelopsis______45, 47, 50, pi. 9 susquaensis, Pinus ______46, 47, 52-53, pi. 9 wiesneri, Matonia.. 49 o