188 DESCEIPTIVE GEOLOGY. 



coarse, gritty, wliite sandstones, about 200 feet in thickness, containing some 

 thin, dark-colored beds, hardened by the oxide of iron, and full of impres- 

 sions of leaves of the elm and alder. These beds dip at an angle of 10° to the 

 south and west, and disappear under the overlying red Tertiaries. , Along 

 the north banks of the river, in ascending, a band of heavy, white and yel- 

 low sandstones, from 200 to 300 feet thick, is exposed, rising at an angle 

 of 5° to 10°, and which abound in impressions of deciduous leaves. Below 

 them is a series of shaly beds carrying coal, which are best seen in section 

 opposite the mouth of Slater's Fork. Here a thickness of about 100 feet is 

 exposed in a bluff made up of thin beds of shales, more or less arenaceous, 

 interstratified with gray sandstones from 2 to 6 feet thick, and carrying 

 three to four beds of coal, of thicknesses varying from 1 to 3 feet. In these 

 beds were found abundant impressions of leaves, and, in some of the clay 

 seams, poorly-preserved fossil remains, whose aspect, as well as that of the 

 lithological character of the beds, has a very close resemblance to the clayey 

 beds observed in the railroad-cut near Bear River City, Utah, which contain 

 fresh and brackish-water species of mixed Eocene and Cretaceous aspect. 

 These beds dip about 10° to the west. Below them, a little higher up the 

 stream, is a bed of heavy, white sandstone, which forms a pretty continuous 

 outcrop nearly up to the mouth of Battle Creek. In Battle Creek, a section 

 of similar beds is exposed, showing sandstone with interbedded clays and 

 some bituminous seams, but no coal. Higher up on the Little Snake River, 

 the only rocks that can be recognized are uncharacteristic white sandstones, 

 still dipping at a very gentle angle. Occasional exposures of sandstone are 

 also seen along the valley of Slater's Fork, while at the eastern base of 

 Crescent Peak, as we have seen, are found dark, clayey beds, upturned at 

 a steeper angle, which have been referred to the Colorado group. The 

 line of Crescent and Camel Peaks seems therefore to mark the first consider- 

 able folding of the underlying Cretaceous beds, while to the north and west 

 they occupy a comparatively undisturbed position. 



Muddy Mountain, which is a broad, flat-topped hill, rising 600 or SCO 

 feet above the general level of the bench country, is made up of white and 

 yellowish blocky sandstones, dipping 5° to 8° to the south and west, which 

 belong to the upper beds of the Laramie Cretaceous. Its very summit is 



