LARAMIE FLORA OF THE DENVER BASIN. 



geologists in New Mexico and Utah point to the conclusion 

 that large deposits of excellent coal occur in the upper 

 Cretaceous. 



In the same report (p. 165) in discussing 

 conditions on the Laramie Plains, he said: 



That there is a connection between all the coal beds of 

 the West I firmly believe, and I am convinced that in due 

 time that relation will be worked out and the links in the 

 chain of evidence joined together. That some of the 

 older beds may be of upper Cretaceous age I am prepared 

 to believe, yet until much clearer light is thrown upon 

 their origin than any we have yet secured I shall regard 

 them as belonging to my transition series or beds of passage 

 between the true Cretaceous and the Tertiary. 



Lesquereux also contributed a short paper 

 to this same report in which (pp. 381-385) he 

 gave a list of all the supposed Tertiary plants 

 of the region known at that date. This list 

 includes 30 species from the " Eo-lignitic " 

 (now Wilcox formation) of Mississippi, 8 

 species from the Raton Pass region (now 

 Raton formation) of New Mexico and Colo- 

 rado, 9 species from Marshall, Colo, (now 

 Laramie formation), 2 species from Golden, 

 Colo, (now Denver formation), and 6 species 

 from Rock Creek, Laramie Plains, Wyo. 

 (now "Upper Laramie")-^* 



In the Fifth Annual Report of the U. S. 

 Geological Survey of the Territories, for 1871, 

 which was published in 1872, Lesquereux has 

 a long report on new plants from localities in 

 Wyoming and Montana, all of which he con- 

 sidered to be of Tertiary age. He also 

 attempted an important generalization in 

 dividing the several localities among the 

 stages of the Tertiary. This may be sum- 

 marized as follows : 



To the Eocene he referred the localities of 

 Mississippi ("Eo-lignitic"); of Raton Pass, 

 Purgatoire Canyon, and Marshall mine, near 

 Denver, Col.; of Washakie Station, Evanston 

 both above and below the coal, and Snake 

 River just below [south of] the Yellowstone 

 Park, all in Wyoming; and 6 miles above 

 Spring Canyon, Mont. To the lower Miocene 

 he referred the Fort Union and Yellowstone, 

 Mont.; Rock Creek, Medicine Bow, Junction 

 Station, and Carbon Station, Wyo.; to the 

 middle Miocene Henrys Fork, Muddy Creek, 

 and Barren's Springs, Wyo., and Elko Station, 

 Nev. The following localities were not at this 



"With the exception of that at the Marshall locality, all the collections 

 above enumerated as Tertiary by Lesquereux are accepted as such at the 

 present day, though for some of them it has required 40 years to establish 

 the truth of Lesquereux's assignment. 



time definitely placed stratigraphically: Green 

 River, Point of Rocks, Sage Creek, and mouth 

 of Spring Canyon. 



In the following year (1872) Lesciuereux 

 himself spent several months in the study of 

 this general field, undertaken at the direction 

 of Hayden, as he somewhat naively remarks, 

 with the "view of positively ascertaining the 

 age of the lignite formations, either from data 

 obtainable in collecting and examining fossil 

 vegetable remains, or from any geological 

 observations which I should be able to make. " 



During this investigation Lesquereux visited 

 and collected from the coal fields of Marshall and 

 Golden in the Denver Basin, Colorado Springs, 

 Canon City, Trinidad, and Raton, and also 

 along the line of the Union Pacjfic Railroad 

 from Cheyenne to Evanston, Wyo. His re- 

 sults -" were considered as confirmatory of his 

 previous conclusions, namely, that the beds at 

 these localities are of Tertiary age and con- 

 stitute what he called the American Eocene 



The same year Meek and Bannister, who 

 were also conducting investigations along the 

 line of the Union Pacific Railroad, made a dis- 

 covery at Black Buttes which, in the opinion 

 of many, had a very definite bearing on the 

 age of the coal of the region. This was the 

 finding of the remains of a huge dinosaur which 

 was named by Cope ^^ Agathaumas sylvestris. 

 In his paper Cope said: 



From the above description it is evident that the animal 

 of Black Buttes is a dinosaurian reptile. * * * It is 

 thus conclusively proven that the coal strata of the Bitter 

 Creek basin of Wyoming Territory, which embraces the 

 greater area yet discovered, were deposited during the 

 Cretaceous period, and not during the' Tertiary, though 

 not long preceding the latter. 



In a short paper published later in the same 

 year Cope,'' in commenting on the discovery 

 of Agathaumas, said : " This discovery places this 

 group [the so-called Bitter Creek series] without 

 doubt within the limits of the Cretaceous 

 period, and to that age we must now refer the 

 great coal area of Wyoming." 



In commenting on the age of the "Bitter 

 Creek series," as the beds at Black Buttes and 

 vicinity were then designated, Meek '^' ex- 

 pressed himself with extreme caution, saying: 



'9 Lesquereux, Leo, Lignitic formations and fossil flora: U. S. Geol. 

 Survey Terr. Sixth Ann. Rept., for 1S72, pp. 317-427, 1S73. 



" Cope, E. D., On the existence of Dinosauria in the transition beds 

 of Wyoming: Am. Philos. Soc. Proc, vol. 12, p. 4S1, 1S72. 



'> Cope, E. D., The ge.ilogical age of the coal of Wyoming: Am, Natu- 

 ralist, vol. 6, p. 669, 1872. 



"Meek, F. B., U. S. Geol. Survey Terr. Sixth Ann. Kept., for 1872, 

 pp. 458, 461, 1873. 



