Mesozoic and Ccenozoic Geology and PalcKoyitology. 257 



geniously mixed with the soil around, so as to make it appear that they 

 came from the decomposition of the sandstone. 



Along Bear river, in Utah, from Bear River City to Evanston, the 

 hills on either side are occupied hy the nearly horizontal beds of the 

 Wasatch Group. The greater part of Bear river plateau is covered, 

 with a considerable thickness of these beds, which are in general rather 

 coarser and more conglomeratic than those of the Aspen plateau. Its 

 summit varies in width from 2 to 4 miles, beyond which to the east- 

 ward these beds are exposed in the deep canons of Woodruff, Randolph 

 and Saleratus creeks, from 2,000 to 2,800 feet in thickness. 



He found the Savory plateau region covered, principall}^ by hori- 

 zontal beds of the North Park Tertiary, which he referred to the Plio- 

 cene, and which, as proved by exposures in the deeper cuts, on its 

 northern edge, overlie the upturned edges of Cretaceous and earlier 

 beds, while the higher portions of the ridges are capped by remnants 

 of the Wyoming conglomerate. The best exposures are found in the 

 open valleys at the heads of Savory- and Jack's creeks, and on the 

 pass between the Archaean bod^- of the Grand Encampment mountains 

 and the Savorj^ plateau. A thickness of not less than 1,000 feet of 

 these beds is here exposed, which is made up in the upper portion of 

 a thickness of about 300 feet of a drab, earthy, somewhat porous, lime- 

 stone, sometimes inclosing small pebbles, underlaid by beds, which 

 grade off insensiblj^ from limy sandstones into coarse gravel beds. 



They occupy the valley of the North Platte to the South of Jack's 

 creek, forming long, gentle slopes, extending up from the river to the 

 flanks of the Grand Encampment mountain, which, though so covered 

 b}' recent deposits that only few exposures of the underlying Tertiar}' 

 are found, sufHcientl}^ show the continuity of their original deposition. 

 Their beds may be traced along the line of bluffs bordering the valley 

 of Sage creek on the south and west. Here the upper member is a 

 hard silicious shale, more like an older rock, under which are seen the 

 white lim}' sandstones ; the lower beds being concealed beneath debris 

 accumulations. 



Arnold Hague found the White River Group along the south and 

 east face of Chalk bluffs, in Wyoming, resting unconformably upon 

 the Laramie Group, and protruding from beneath the Pliocene beds. 

 The strata are exposed near Carr's station, on the Denver Pacific 

 Railroad, eastward across Owl creek, the tributaries of Crow creek, and 

 beyond. The thickness of the group is estimated at 300 feet, and is 

 of Miocene a^e. 



