740 ARTHUR C. TROWBRIDGE 



leave their fans and locate their main channels in the inter-fan 

 depressions. Deposition then takes place in the depression, build- 

 ing it up and making a fan across the edges of two earlier fans. 

 Presumably streams will shift back to their original positions when 

 those positions have become lower than the site of the original 

 depressions, through deposition in the latter. Streams then shift 

 from fans to depressions, make fans there, shift back, build up the 

 old fans, shift again, etc. How frequent and important this may 

 be is not clear. If streams shift freely from higher places to depres- 

 sions, it is surprising that fans of the bajada stand 200 ft. above 

 the low places between them. The general relief of the bajada 

 should be very slight. The water forming depositing streams 

 probably does not adjust itself freely to the low places, though it is 

 clear that it does so in many cases. The origin of the diverging 

 channels is clear. 



THE TRANSPORTATION OF LARGE BOWLDERS 



One could hardly travel a mile on the Sierra bajada, or see the 

 heads of the fans at the foot of the Inyo Mountains without asking 

 how the large bowlders came to their present positions. It is 

 essentially a problem of the means of transportation of the largest 

 bowlders farthest from the mountains, for if they can be explained, 

 the smaller bowlders may be considered to have been carried shorter 

 distances by the same methods. Probably the most difficult 

 problems are offered by the largest bowlders, such as those west of 

 Lone Pine, 6 miles from the mountains, measuring 10X20X30 ft. 

 above ground, and the one at the Cerro Gordo power shanty, larger 

 than the one first mentioned and i| miles from the mountains, 

 and several others in that vicinity about as large. 



It is clear that these bowlders came to their present positions 

 through the agency of water. Though their size suggests glaciers 

 as the transporting agents, such an explanation is out of the ques- 

 tion. The lower limit of glaciation is distinctly marked in the 

 mountain canyons above. The glaciers did not descend to the 

 plains. Nor is there anything in the fact of icebergs floating in 

 a lake. The deposits with which the bowlders are associated are 

 not lacustrine, and no lake existed in the valley during glacial 



