WASHAKIE BASIN. 209 



series. To the south of this ridge, an arm of the desert makes in, in which 

 the underlying rocks are concealed by accumulations of sand, which have 

 been driven in here by the prevailing west winds from the desert region to 

 the westward. To the west, the Laramie beds, which were crossed in sec- 

 tion north of the Little Muddy, bend in strike to the southward, with a low, 

 westerly dip, and gradually disappear under the decomposed beds of the 

 Vermillion Creek series. 



The eastern border of the map, from -this ridge as far south as the Little 

 Snake River, represents the western edge of the bench-country, between 

 the Little Muddy and the Park Range, which has already been described in 

 Chapter I, and is formed of beds of the Laramie group, having a dip of about 

 5° to the westward. The western foot-hills of this bench-country, along the 

 east side of the Little Muddy, are occupied by a series of loosely-aggregated 

 sand-rocks, of chocolate, buff, and gray colors, which represent the base of 

 the Vermillion Creek series. The only fossil remains found in tliese beds 

 were rough casts of Goniobasis and Viviparus, in a yellow sandstone, which 

 was considered to represent the base of the series ia this region. 



On the western borders of the Little Muddy Creek, the characteristic 

 upper beds of the Vermillion Creek series are exposed, weathering in castel- 

 lated forms, and easily recognized even from a great distance by their 

 bright pinkish and reddish coloring. They consist of an intimate admixture 

 of sands, clays, and marls, in varying proportions, which are more or less 

 colored by oxide of iron. The lines of stratification in these beds are 

 indicated rather by difference of color than by change in the material of 

 which they are composed. The colors vary from a greenish-white to a 

 deep, almost brick, red, which give to the bluff exposures a peculiar striped 

 appearance, characteristic of this formation. The soil Avhicli results from 

 their decomposition is a light, clayey material, of a peculiarly red color, 

 from which the sandy constituents seem to have been washed out. The 

 best exposures of these beds are seen at Washakie Mountain and at Ca- 

 thedral Bluffs. 



Washakie Mountain is a flat-topped ridge, about 8 miles east of the 

 Little Muddy, which attains an elevation of some 1,500 feet above the sur- 

 rounding plains. It is capped by a remnant of the Wyoming Conglomerate, 



14 D G 



