RESUME OF LITERATURE. 29 



mountains in 1871. He describes the structure of the Uinta Range with some 

 accuracy, though stating that the upheaval took place not long subsequent to the 

 Carboniferous epoch (p. 1112). "The uplifted beds," he saj's, "as displayed by 

 the lateral erosion, are almost entirely composed of a brownish-red sandstone, 

 rarely, if at all, fossiliferous, of the Subcarboniferous epoch, the color rarel}' 

 changing into gvay. * * * Thej' are of very great thickness, from 2,000 to 

 3,000 feet, being visible near the summit. Higher up in the series, and lying along 

 the base of the mountains toward Green River, the Carboniferous beds of soft, 

 bright yellow sandstone, coarse conglomerate, blue limestone (quite rare and thin), 

 and gypsum (in thin seams) are exposed. * * * The series above the Carbon- 

 iferous either do not occur or are overlaid by a highl}' fossiliferous deposit of 

 Tertiarj^ age. This deposit lies nearly horizontal, and is composed of soft yellow 

 and red marls, greensand, and thin beds of soft limestone and chert" (p. 1113). 

 Apparently the Carboniferous of this account forms part of the Mesozoic of PowelFs 

 Uinta Mountains report, and the geologic age, determined as Carboniferous, must 

 have been assigned, I fear, because of its contained coal seams. Jones's Subcar- 

 boniferous is with little doubt the Uinta sandstone of Powell's report, and he 

 determination of its age apparently depends upon the fact that it lies under the 

 coal-bearing series thought to be Carboniferous. 



A report by Powell upon the geology of the IMnta Mountains, published in 1876, 

 and the reports of the Fortieth Parallel Survey which appeared almost immediately 

 after, discuss the geology of considerable Carboniferous areas in northwestern Colo- 

 rado, and remain at the time of writing almost the only accounts, as they are cer- 

 tainly the most comprehensive ones, of the subject. These reports, together with 

 one by White published subsequently and that by Jones alread}' referred to, consti- 

 tute the entire literatuie of the Uinta area, and it is all too meager and contradictory. 



In the case of the Fortieth Parallel Survey the actual explorations were made 

 by Hague and Emmons," whose accounts constitute volume 2 of that series. The 

 volume on systematic geology by King (vol. 1), however, which is a restatement 

 of their facts and a general discussion based upon them, is a more convenient and 

 suggestive form in which to consult these data. 



Powell's observations, as already said, are embodied in the volume upon the 

 geology of the Uinta Mountains,'' which contains a relatively length}' paleontologic 

 discussion by C. A. White, who subsequently published in the Tenth Annual Report 

 of the Ha3'den Survey an account, based upon independent observations, of the 

 geology of a part of the Colorado Uinta area, and also several briefer papers 

 recapitulating much of the same matter. 



The title of Powell's work is somewhat misleading, as his discussion is mainly of 



<i U. S. Geol. Expl. 40th Par., Rept., vol. 2, 1877. 



l> U. S. Geol. Geog. Surv. Terr., Powell's Rept. Geol. Uinta Mountains, 1876. 



