PHYSIOGRAPHY OF BISHOP CONGLOMERATE 607 



area studied were noticeable irregularities in the surface evident 

 in the exposed line of contact with the underlying rocks. In 

 several places, but best along the eastern face of Little Mountain, 

 this contact can be seen continuously for several miles, and in 

 all that distance does not display any appreciable irregularity. 

 The probable reason for this great regularity is that the under- 

 lying rocks are uniform in texture and quite soft. In localities 

 where the underlying rocks are markedly unequal in hardness the 

 contact is slightly irregular in detail, but still regular in general. 

 A large part of the gravel-capped plateau Hes on the truncated 



Fig. 4. — Unconformity of Bishop Conglomerate with underlying Cretaceous 

 rocks southeast of Aspen Mountain. The dark horizontal bed at the top is the con- 

 glomerate. Note how evenly the base of this conglomerate truncates the dipping 

 sandstones beneath. This is typical of conditions all along the edge of the plateau. 



crest of the Rock Springs dome, a broad anticline of sedimentary 

 rocks about ninety miles in length with the long axis running a 

 little west of north through Aspen Mountain. This anticline has 

 a total width of about forty miles. In the southern part of the 

 area the plateau truncates the tilted rocks on the northern flank of 

 the Uinta uplift. The beveling of the underlying rocks by the 

 plateau-surface is very marked. In certain parts of the Rock 

 Springs dome these underlying rocks dip in both directions from the 

 crest, sometimes at an angle as high as 35°, yet the plateau-surface 

 cuts evenly across them entirely irrespective of structure and 

 almost irrespective of hardness (Fig. 4). Faults and folds in the 

 underlying rocks have no expression in the plateau-surface. 



