st. johx.] BUFFALO FORK REGION. 467 



similar beds with additional members are found dipping in the opposite 

 direction 89°. Between tliese points no Cretaceous exposures were no- 

 ticed, but judging from the dips of the lower sedimentary strata, which 

 were observed on Lava Creek between Camps 55 and 56, there must be 

 one or more folds intervening." * Also reference is made to "the coal- 

 bearing series on Buffalo Fork. The strata containing the coal are nearly 

 vertical and in folds, so that the beds are several times exposed in the 

 canon within a short distance. Much of the coal is very good."t 

 Professor Comstock regarded all these strata as of Cretaceous age. From 

 the above observations it would appear that these deposits had been 

 greatly disturbed by elevatory forces seated in the Buffalo Fork Mount- 

 ain, which refers this uplift to a late date. Other strati grapical appear- 

 ances observed in the northwest flank of this mountain group will be 

 noticed farther on. 



Sufficient has been observed to show that the bulk of the divide be- 

 tween the Buffalo Fork and the drainage flowing north into the upper 

 course of the Snake is made up of the soft arenaceous clays and sand- 

 stones of this lignite-bearing series of probable Tertiary age. Professor 

 Comstock is not quite sure as to their stratigraphical identity, but from 

 lithologic resemblances and the presence of coal, he was induced to re- 

 fer them to horizons hi the Wind Eiver region which he determined pos- 

 sess close affinities with the Cretaceous. These deposits, which attain a 

 great thickness, probably above 3,000 feet, apparently occupy anexten- 

 sive basin whose limits, so far as they have been traced, are defined by 

 the Teton Eange on the west, the Gros Ventre Bange on the south, and 

 on the north their present limits correspond with the uplifted Palaeo- 

 zoic belt in the vicinity of the confluence of Lake Fork and the Snake, 

 which appears to be the remnant of the southeast flank of a great fold, 

 the crest of which lias suffered almost complete demolition by denuding 

 agencies, and was finally buried beneath a vast accumulation of volcanic 

 materials in the region of the plateau of the Continental water-shed. To 

 the northeast they pass beneath the volcanics which, according to Pro- 

 fessor Comstock, compose the crests of the Shoshone Eange and an 

 extensive mountainous region to the east at the sources of Gray Bull 

 and Stinking Water Eivers, and which, to the west, as seen from Station 

 XL VIII, constitute the elevated watershed ridge, in which great escarp- 

 ments of the peculiarly banded gray and sombre volcanics appear, dip- 

 ping slightly northeastward, and eroded into broad-based peaks and lofty 

 promontories. 



In the midst of this basin rises the apparently isolated cluster of 

 mountains which culminates in Buffalo Fork Peak. This group seems 

 to be quite disconnected from the surrounding mountain ranges, form- 

 ing a great dome-shaped mass, the upheaval of which has brought to 

 view the metamorphic nucleus, several hundred feet of which are re- 

 vealed in the rugged walls of the canon of Buffalo Fork. But to the 

 east of this group the connection of the Tertiary deposits with similar 

 beds at the head of Wind Eiver Valley is lost beneath the southern ex.- 

 tension of the before-mentioned volcanics in the neighborhood of To- 

 gwotee Pass ; to the south of which, however, they reappear in the ridges 

 of the Mount Leidy highlands which sweep up on and in places even 

 crown the summit of the watershed between the Togwotee and Warm 

 Water or Union Passes, as was inferred by Dr. Hayden. 



* Report upon the Reconnaissance of Northwestern Wyoming, under Capt. Wm. A. 

 Jones, Engineers XL S. A., 1873 ; Geological Report by Prof. Theo. B. Comstock, p. 120. 

 Mb., p. 152. 



