TERRESTRIAL DEPOSITS OF OWENS VALLEY 743 



This is conceived to be possible. The process is greatly aided 

 by the momentum obtained by the bowlder when it first moves 

 toward the depression. The depression below the bowlder would 

 not be deep, before the crowding of the material above, and the force 

 of water and gravity would force the bowlder into it. The depres- 

 sion would play out very gradually down slope, giving a constant 

 gradient down which the bowlder could roll, slide, or creep. 



Obviously this process would operate to best advantage where 

 there was the greatest volume of water, and where fluctuations of 

 water were greatest; that is, along the main channels of the fans, 

 and on the Sierra fans rather than at the foot of the Inyo Mountains. 

 Bowlders are usually arranged in lines related to the channels, 

 and they are more abundant and larger on the Sierra bajada than 

 at the foot of the Inyos. If this method of transportation of large 

 bowlders is not adequate, methods which are, are not known. 



LENS AND POCKET STRATIFICATION 



It was shown above (pp. 717-22 and 735-37) that the materials of 

 the fans of the region are but crudely sorted, and that the different 

 textural grades take the forms of lenses and pockets, rather than 

 definite and continuous layers. No textural division was traceable 

 more than 50 ft. in any cut, before it played out in one direction or 

 another. The explanation of this seems clear. 



On the surfaces of all the fans in the region are numerous 

 radiating channels and low ridges. In Mazourka Canyon, these 

 channels are braided in almost all directions, though along lines 

 trending generally down valley. These surfaces represent the last 

 deposition on the respective fans. Beneath the present surface 

 there must be many similar surfaces, made and buried as the fan 

 was built. 



When flood waters flow over a fan, radiating channels are formed. 

 As the flood subsides, or if the waters are overloaded otherwise, 

 deposition takes place in the channels. The channels are filled 

 with whatever grade of material the stream finds itself unable to 

 carry, and the stream is forced over the side. It then makes a 

 new channel, fills it, and overflows to repeat the process. The fan 

 grows by the addition of long narrow strips of material, sorted 



