66 



LARAMIE FLORA OF THE DENVER BASIN. 



beds like that at Black Huttot! and containing many of 

 the same characteristic species of fossils in the sane strati- 

 graphic order. 



As iilreiuly pointed out, tlic foul ami plant 

 hearing section at Point of Rocks liad for many 

 years been regarded as belonging in tlie 

 Laramie, ami tlie flora especially had come to 

 ])(' ivnown as a "true Laramie flora," although 

 it iiad long been recognized tliat it was '"some- 

 wliat different from that of any other locality 

 in the West." In accordance with tlie dis- 

 covery above set forth, that the coal and plant- 

 bearing rocks were some hundreds of feet below 

 well-definel marine Cretaceous, a readjustment 

 became necessary. These facts arc set forth at 

 some length in my paper on the "Flora of the 

 Montana formation," -^ published in 1900. 



In the summer of 1907 A. R. Schultz -" 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 tlie 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 " 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. 



SOTTTHWESTEKN 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- 



«i Knowlton, F. H., V. S. Geol. Survey Bull. 163, 1900. 



'• The northern part of the Rock Spring.s coal lleUi, Sweetwater County, 

 Wyo.: U. S. Geol. Survey Bull. 341, pp. 2.18-282, 1909. 



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

 Wyo.: U. S. Geol. Survey Bull. 381, pp. 214-2S1, 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.^' 



In connection with the coal at Evanston fossil 

 plants were discovered at an early day, and 

 the locality has been studied by Hayden, Peale, 

 Lescjuereux, Newberry, Ward, and many others. 

 Lesquereux '' alwaj's regarded the plants as 

 indicating a Tertiary age, and in his final report 

 he placed the Evanston locality in his so-called 

 "second group," which included also Mount 

 Bross and Troublesome Creek, in Middle Park, 

 Colo., and Bridger Pass, Wyo. Newberry ''" 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 1S78 C. A. White ^' 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 ^- described a number of plants 

 from ICvanston 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 \\Tiite ^^ went a step further 

 and referred the coal-bearing series at Evanston 

 to the Wasatch on the groimd that sedimen- 

 tation was continuous from the undoubted 

 Cretaceous through the Laramie and into the 

 W'asatch, and, moreover, the invertebrates, 

 before supposed to be characteristic of the 



^s \ complete bibliography of works relating to the geography and 

 geology of this region is given by A. C. \'eatch (Geography and geology 

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

 .W, pp. 17 32, 1907). 



" Lesquereu.\, Leo, The Tertiary flora: U. S. Geol. Survey Terr. Rept., 

 vol. 7, 187K. 



" Newberry, J. S., On the lignites and plant beds of western .\merica: 

 Am. Jour. Sci., 3d ser., vol. 7, p. 4(X), 1S74. 



" On the distribution of moUu-scan species in the Laramie: V. S. Geol. 

 and Oeog. Survey Terr. Bull., vol. 4, p. 722, 187S. 



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

 .Ml ct seq., 1SS6. 



'" 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, p'ji. 9-16, 1886. 



