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



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Behind it to the south is a flat terrace of river silt and gravels, 

 at a considerable elevation, fifty to one hundred feet, above the 

 floor of the valley to the north. (PL 23b). The absence of care- 

 ful topographic work and of surveys by the writer leaves the 

 exact difference in the elevation yet to be determined. The rock 

 buttress, or earth block, is capped with andesite, and the under- 

 lying granodiorite shows many small east-west dikes of the same 

 rock. On the east ridge-crest is a prominent scarp facing north, 

 on the line of the low place in the west crest. A little to the 

 south of this is a second and smaller break and rise on the south 

 side, which can be followed eastward down a shoulder and east- 

 west scarp precisely similar to the shoulder above and west of the 

 valley. Eastward from the foot of this lower shoulder and east- 

 west scarp the line crosses a southerly projecting finger of Washoe 

 Valley. As in Little Valley, the valley floor is broken along the 

 line and is elevated on the south side. In the absence of an exact 

 topographic survey, the precise elevation is not now known, but 

 it is between ten and twenty feet, with the low fault-scarp in the 

 soft alluvium and gravels almost entirely degraded. The dis- 

 tance is less than in Little Valley. There occurs a well-defined 

 fault crossing the east ridge just south of the larger fault-line 

 just described. The gully caused by this fault terminates, on the 

 north, the higher portion of the east ridge, and is followed for a 

 distance by the road into Little Valley. 



This southern portion of Little Valley is in its turn divisible 

 into two dissimilar portions, each with its own peculiar and 

 significant features. A lower portion lies between the jog in the 

 creek before described and the turn in the creek to the south- 

 east, proceeding toward its head. The second part lies south of 

 this, and contains that part of the creek that flows northwest. 

 The lower or northern portion is the most constricted and gorge- 

 like part of Little Valley, and has the highest average grade. 

 As in all other parts of the valley, however, the creek is cutting 

 in loose material, with no solid rock yet exposed. It is in this 

 part of the valley that the profile of the walls is especially signifi- 

 cant. Both east and west slopes show, not smooth curves, but a 

 series of a few huge steps leading down from the summits into 

 the valley. The largest step on the east side of the valley is 



