GEOLOGY OF THE COSO RANGE 



69 



are found, but no such rocks were noted in place. The greatest 

 thickness of the beds is about two hundred feet, with the base not 

 exposed. In areal extent they persist from the basalt ridge on the 

 north (see Fig. 4) to a low easterly spur of granite about eight miles 

 north of Darwin. From this ridge southward the beds were not seen 

 except in the exposures west of Darwin. The highest elevation is 

 on the low granite spur, 60 feet above the bench mark of the U. S. 

 Geological Survey marked elevation 5,101 feet. Here the section 



Fig. 5. — Basalt-covered low south end of Inyo Range, looking southeast from 

 Keeler. Shows the intense faulting of the late basalt flows resting on the old sedimen- 

 taries and Tertiary lake beds low down. 



is small but complete. On the crystalline base, nearly horizontal, 

 is roughly one hundred feet of well-stratified granitic sandstone, with 

 one foot of reddened material at the top, overlaid by basalt. There 

 is a slight northerly dip. Just south of the point of greatest elevation 

 the stratified rock lies horizontal at a lower elevation. 



In the basalt-covered portion of the low south end of the Inyo 

 Range similar arenaceous beds are burned by volcanic flows (see 

 Fig. 5). East of Keeler, above the deposits of the older Owens Lake, 

 occurs a large amount of sand, which may, and probably does, repre- 



