154 GEOGRAPHIC DISTRIBUTION. 



They have a much more extensive development on the south than on the 

 north side of the Uinta Mountains. 



. On the south side of the Yampa Plateau, where the Fox Creek and 

 Cliff Creek flexures unite, the.se conglomerates stand on edge with a dip of 

 about 85 degrees to the southeast, and are firmly cemented, and stand as 

 high walls, separated by a long, narrow valley, strewn with fragments of 

 the conglomerate which have tumbled down from either side. Farther east, 

 along the southern slope of the Yampa Plateau, they are very conspicuous 

 features in the topography, as they are found standing in ridges and monu- 

 ments. Here the topography is exceedingly complex, too much so to be rep- 

 resented on the map which presents but a crude generalization of the many 

 wonderful features of this region. 



SULPHUR CEEEK GEOUP. 



These beds are soft argillaceous and arenaceous shales of dark color, 

 but sometimes weathering a light gray. By reason of their exceeding fria- 

 bility the areas of outcrop are everywhere valley regions, often diversified 

 with broad stretches of low, bad-land hills in many places quite naked of 

 vegetation, but elsewhere covered with patches of cactacece. Conspicuous 

 among these is a species of opuntia, with its minute, subtle thorns hedging 

 the hills with a threat of festering wounds. 



Its most extensive area of outcrop is in the Island Park sag, and it has 

 a small outcrop in the northern portion of the Aspen Mountain uplift. 



A fragment of these beds is seen southeast of Diamond Peak, which, 

 with a fragment of the Flaming Grorge beds on one side and a fragment of 

 Salt Wells on the other, is standing on edge. It will be noticed that these 

 beds dip toward the axis of upheaval, that is, the highest beds are found 

 nearest the mountain, and they all stand with an inclination from the horizon 



of 90 degrees. 



SALT WELLS GEOUP. 



It is unnecessary to speak in detail of the outcrop of the Salt Wells 

 beds, as the attention of the reader has already been called to the outcrop 

 on the flanks of the Uinta Mountains and in the Aspen Mountain district. 

 It is worthy o.f remark that in the Uinta Mountain region these beds are 



