736 ARTHUR C. TROWBRIDGE 



the head of the main fan the entire surface is so covered with them 

 that a horse cannot travel over it. The average size of the bowlders 

 is about itj ft. Their number and size can be seen in Fig. 23. The 

 photograph was taken from fan No. 8. 



These bowlders show little shaping. If fragments were broken 

 from ledges by the wedge work of ice and gravity, and then the 

 sharp and irregular edges dulled during a short period of transpor- 

 tation, their present shape would result. Neither glaciation nor 

 prolonged rolling has affected them. 



'"% 



^^•^"If J* 





Fig. 24. — Angular material in the fans at the foot of the Inyo Mountains 



The fine material on the surface of the fans occurs in largest 

 areas near the outer edges, where there are few bowlders, and the 

 surface material has about the texture of fine gravel or coarse 

 sand. A half-mile from the edge it is made of fragments more 

 or less shaped by transportation, averaging perhaps 3 in. through, 

 with some lines of larger bowlders. At the head the surface is 

 practically covered with bowlders. 



Although exposures of material beneath the surface are almost 

 wanting, a few shallow cuts were seen. The data they afford 

 follow : 



1. In the outer edge of fan No. 8, 4 miles south of Aberdeen, 

 is a pit dug as a placer prospect, 10 ft. deep, 15 ft. long, and 

 5 ft. wide. The material is all fine, there being nothing as large 



