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



159 



Eagle Valley and the northern part of Carson Valley have also 

 experienced a similar tilting. These small diastrophic move- 

 ments are probably still taking place. 



It is easily possible to write a story of the faulting over the 

 remainder of the area, but as all the details have not yet been 

 gathered such a course would be of little value. There can be 

 no question about the occurrence of the several periods of fault- 

 ing elsewhere, however, and that the geomorphic evolution of the 

 Tahoe basin is vitally and minutely connected with these move- 

 ments, particularly on the east side. The work of translating 

 this history still remains to be accomplished, and presents a very 

 fascinating field for study. 



OTHEE IMPORTANT STRUCTURAL FEATURES ELSEWHERE. 



There are a few suggestive structural features both on and 

 just off the mapped area that deserve attention in this paper, 

 both because of relation to the facts herein presented, and 

 because of their presenting further unsolved problems connected 

 with the geomorphogeny of the Sierra Nevada. 



Carson and Truckee Rivers. 



Some details of the history of the Carson River have been 

 given, showing a tilting of a part of its valley to the east. A few 

 more important features need to be given, and some similar 

 characteristics of the Truckee River and its valley cited for the 

 sake of comparison, to show the general nature of certain dias- 

 trophic movements. The old course of the Carson River has 

 been shown to be along the base of the hills at the west of the 

 valley, and that its present course is due to tilting of the valley 

 to the east. In that part of north Carson Valley, a few miles 

 west of Prison Hill, there are found the remains of three river 

 terraces. The rough outlines of these are shown by dotted lines 

 on the topographic map. Their elevations are respectively 5,250, 

 4,950, and 4,850 feet. The valley is at an elevation of 4,650 feet. 

 Some of the difference in elevation of terraces and valley is due 

 to faulting, as has been set forth ; some appears due to the actual 

 stream terracing. The material of all the terraces is gravelly, 



