66 



LARAMIE FLORA OF THE DENVER BASIN. 



beds like that at Black Buttes and containing many of 

 the same characteristic species of fossils in the sane strati- 

 graphic order. 



As already pointed out, the coal and plant 

 bearing section at Point of Rocks had for many 

 years been regarded as belonging in the 

 Laramie, and the flora especially had come to 

 be known as a "true Laramie flora," although 

 it had long been recognized that it was "some- 

 what different from that of any other locality 

 in the West." In accordance with the dis- 

 covery above set forth, that the coal and plant- 

 bearing rocks were some hundreds of feet below 

 well-defined marine Cretaceous, a readjustment 

 became necessary. . These facts are set forth at 

 some length in my paper on the "Flora of the 

 Montana formation," 25 published in 1900. 



In the summer of 1,907 A. R. Schultz 2n and 

 party investigated the resources of the northern 

 portion of the Rock Springs field and gave a 

 brief account of the geologic relations. The 

 Point of Rocks coal and plant bearing beds, as 

 well as the upper coal measures at Rock Springs, 

 were called the Almond coal group, which was 

 referred to the Mesaverde formation. It is 

 separated by the marine Lewis shale (750 ± 

 feet) from the overlying Black Buttes coal 

 group, which was classed as Laramie (?). 

 Schultz's results thus confirmed the observa- 

 tions of Meek and Bannister regarding the plac- 

 ing of the Black Buttes coal beds well above 

 the Point of Rocks coals and those of Stanton 

 and Knowlton in recognizing a marine Creta- 

 ceous formation between the two groups of 

 coals. 



In 1908 Schultz 27 continued this study to 

 include the southern part of the Rock Springs 

 field. No change was made in the stratigraphic 

 assignment of the coal and plant bearing beds 

 under consideration. 



SOUTHWESTERN WYOMING. 



Within an area about 40 miles wide and 175 

 miles long, in Uinta and Lincoln counties, in 

 the extreme southwest corner of Wyoming, 

 there are numerous economically important 

 deposits of coal, and the area has been often 

 visited and more or less critically studied by 

 geologists. The geologic relations in the vicin- 



25 Knowlton, F. H., U. S. Geol. Survey Bull. 163, 1900. 



2« The northern part of the Rock Springs coal field, Sweetwater County, 

 Wyo.: U. S. Geol. Survey Bull. 341, pp. 256-282, 1909. 



"The southern part of the Rock Springs coal field, Sweetwater County, 

 Wyo.: U. S. Geol. Survey Bull. 381, pp. 214-281, 1910. 



ity of Evanston have been frequently alluded 

 to in the first portion of this discussion, and 

 hence it is only necessary in this connection to 

 call attention to a few of the more salient 

 points before reviewing the present accepted 

 status. 28 



In connection with the coal at Evanston fossil 

 plants were discovered at an early day, and 

 the locality has been studied by Hayden, Peale,- 

 Lesquereux, Newberry, Ward, and many others.' 

 Lesquereux 29 always regarded the plants as 

 indicating a Tertiary age, and in his final report 

 he placed the Evanston locality in his so-oalled 

 "second group," which included also Mount 

 Bross and Troublesome Creek, in Middle Park, 

 Colo . , and Bridger Pass , Wyo . Newberry 30 ex- 

 pressed the opinion that these plant beds, as 

 well as practically all lignite-bearing beds in 

 Wyoming and Utah, were Cretaceous, and 

 hence when the Laramie was established they 

 were naturally referred to this time division. 

 In 1878 C. A, White 31 included the "Evanston 

 coal series" in the Laramie and gave a list of 

 four species of invertebrates common with the 

 Judith River beds. 



In his "Synopsis of the flora of the Laramie 

 group" Ward 32 described a number of plants 

 from Evanston and Hodges Pass; the latter 

 locality, he stated, "may be regarded as form- 

 ing a northern member of the Evanston coal 

 field." Evanston and Carbon were placed 

 together in the table showing the extent and 

 range of the Laramie flora as he accepted it, 

 and both were regarded as belonging in its 

 upper portion. 



Two years later White 33 went a step further 

 and referred the coal-bearing series at Evanston 

 to the Wasatch on the ground that sedimen- 

 tation was continuous from the undoubted 

 Cretaceous through the Laramie and into the 

 Wasatch, and, moreover, the invertebrates, 

 before supposed to be characteristic of the 



1 8 A complete bibliography of works relating to the geography and 

 geology of this region is given by A. C Veatch (Geography and geology 

 of a portion of southwestern Wyoming: U. S. Geol. Survey Prof. Paper 

 66, pp. 17-32, 1907). 



»• Lesquereux, Leo, The Tertiary flora: U. S. G eol. Survey Terr. Rept., 

 vol. 7, 1878. 



80 Newberry, J. S., On the lignites and plant beds of western America: 

 Am. Jour. Sci., 3d ser., vol. 7, p. 400, 1874. 



81 On the distribution of molluscan species in the Laramie: U. S. Geol. 

 and Geog. Survey Terr. Bull., vol. 4, p. 722, 1878. 



® Ward, L- F., U. S. Geol. Survey Sixth Ann. Rept., for 1884-85, pp. 

 541 et seq., 1886. 



88 White, C. A., On the relation of the Laramie molluscan and fresh- 

 water Eocene fauna to that of the succeeding fresh-water Eocene and 

 other groups: U. S. Geol. Survey Bull. 34, pp. 9-16, 1886. 



