PHYSIOGRAPHY OF BISHOP CONGLOMERATE 623 



must have been relatively much greater than that of the gravel- 

 capped plateaus. This is not unreasonable, for one would expect 

 that denudation would be more effective in the mountains, exposed 

 as they are to the excessive action of frost and wind, with steep 

 slopes and highly inchned rocks, than in an adjacent lower region 

 of nearly horizontal rocks, even though the rocks in the mountains 

 are harder. Then too, in the case of the Uintas, Green River flows 

 through them in a deep canyon. This gives steep slopes and con- 



FiG. 8. — -A tjTsical exposure of the conglomerate on the south face of Little Moun- 

 tain. This is a view looking southeast into Red Creek basin, the bottom of which 

 lies some 2,500 feet below. The outlying ranges of the Uintas may be seen in the 

 background to the right. Red Creek valley lies between the plateau and the moun- 

 tains. This view gives some idea of the character and immense amount of erosion 

 which has been accomplished since the conglomerate was laid down. (Photo, by 

 A. R. Schultz.) 



sequently more rapid erosion of the adjacent mountains than of 

 th^ plateaus farther away. As to the alternative of a downthrow 

 of the mountain-block since the gravels were deposited, there is 

 some uncertainty. The principal uplift of the northern flank of 

 the Uintas took place along a fault whose maximum displacement 

 amounted to over 25,000 feet, but there seems to have been a cer- 

 tain amount of downthrow as well as uplift along this fault-zone. 

 PowelP described such a downthrow running in an east-and-west 

 direction south and southeast of our area, which he believed had 

 lowered the mountain-block by from 1,000 to 3,000 feet in various 



I Powell, Geology of the Uinta Mountains, 204-6. 



