Vol. 6] Beid: The Geomorphogeny of the Sierra Nevada. 



155 



long, narrow granite blocks whose features have been given. 

 They cannot be due to erosion, for they bear no fixed relation to 

 drainage lines. The possibility of glacial action cannot be con- 

 sidered, for not only were glaciers absent here but also the 

 seeming piles of granite boulders are solid rock beneath the sur- 

 face covering, even though badly fractured. The aspect of this 

 portion of Little Valley is as if it had been squeezed between 

 powerful jaws, breaking the valley floor and forcing some small 

 blocks broken therefrom above the general level. This is in 

 entire harmony with the mode of formation of the valley pre- 

 sented later. 



Block 2, opposite the central portion of Little Valley, seems 

 to have suffered no differential elevation, but is broken by a cross- 

 fault at about its center. North of the center line the axis of the 

 block strikes east and north ; to the south the strike is slightly 

 east of north. The general crest line, however, parallels the 

 high west ridge. The north end slightly overlaps the south end 

 of block 1, and does not abut squarely against it. The fault- 

 lines in this section of the valley are the same as to the north : 

 one at the base of the high west ridge, and two on the west side 

 of the plateau remnant on the low east ridge. All these lines are 

 roughly parallel, so that the wide central portion of the valley is 

 rectangular. 



Block 3 has been elevated with respect to block 2, and also 

 tilted a little to the north. The main line of east-west faulting, 

 which bounds it on the north, is well shown in plate 27b by a 

 prominent scarp and the group of andesite outcrops upon it. 

 The block has moved eastward relative to block 2 and westward 

 relative to block 4. The northeast-southwest fault separates 

 blocks 3 and 4 in a precisely similar manner to the separation of 

 blocks 1 and 2 by a parallel fault. The north end of block 4 

 swings to east of north, overlapping block 3 in the same way 

 that block 2 laps 1. 



Block 4, for the present purposes, may be considered reach- 

 ing to the south limits of Little Valley. Actually, however, the 

 southern portion of the block is broken by two-cross faults, along 

 which the south walls have moved eastward. South of Little 

 Valley lies another center of elevation, corresponding to Slide 

 Mountain, whose culminating point is Snow Valley Beak. 



