WASHAKIE BASIN. 213 



beds have a dip of about 4° to the southeast, and strike north 45° east. In 

 the valleys, both north and south of this peak, the red clays of the Vermil- 

 lion Creek series are exposed, which, as seen under the cliffs near the 

 stage-road, to the south of Table Eock, seem to show a n on- conformity of 

 dip of 3°. They are overlaid by beds of a calcareous sandstone, formed 

 almost entirely of an aggregation of fresh-water shells, which is sufficiently 

 compact to have been used as a building-stone for the stations of the old 

 stage-road. From the line of Table Rock and Pine Bluff westward to the 

 Bitter Creek Ridges, in the neighborhood of Black Butte Station, is a low 

 open country, in which the Vermillion Creek beds have been so thoroughly 

 disintegrated that few exposures of rock are found. The presence of the 

 upper reds beds of this group is characterized, along the base of the bluffs, 

 formed by the calcareous beds of the Green River series, by the peculiar 

 red tinge of the soil. The lower beds of this series, which are composed 

 mainly of coarse sandstones, differ so slightly in lithological character from 

 the underlying Cretaceous rocks that their line of separation cannot be 

 accurately drawn, where, as here, there is no appreciable discrepancy of 

 angle between the two formations. 



The most characteristic development of the beds of the Green River 

 series, in this region, is in the neighborhood of Pine Bluffs, which form a 

 prominent landmark in the eastern basin. Their highest point is composed 

 of about 400 feet of yellowish calcareous sandstone, dipping 4° to 5° to the 

 south of east, with a strike a little east of north. Under tliese, as shown in 

 the bluffs to the north, are soft, white, shaly beds of a thickness of several 

 hundred feet. In the ravines, on the eastern slopes of the bluff, occasional 

 thin sandstone beds are observed, but, in general, the underlying rock is 

 completely obscured by great accumulations of detrital material. Near the 

 springs, about 10 miles northeast of Pine Bluffs, at the source of Bitter 

 Creek, are exposures of thin, blue, calcareous shales, which are peculiarly 

 characteristic of the Green River series. They are extremely fissile, split- 

 ting up into laminae whose thickness is scarcely more than that of a sheet 

 of paper, and are generally more or less impregnated with carbonaceous 

 material. Their weathered surfaces are generally white, or a pale bluish 

 gray. They are found in the h'lls both to the east and west of the springs, 



