1912] 



Baker: Western El Paso Range 



139 



middle of the old age stage. As one goes northward the surface 

 rises steadily in altitude until west of Mount Whitney it is on 

 the average 11,000 feet above the sea, whereas in the vicinity of 

 Walker Pass it has an average altitude of from 6,500 to 7,000 

 feet. In the Mount Whitney region the peaks of the Great 

 Western Divide and the main Sierra crest rise 2,000 feet and 

 more above its general surface, the highest peak of all, Mount 

 Whitney, rising some 3,500 feet above it. Here the stage of 

 erosion reached at the culmination of the cycle was not developed 

 further than early old age. We have good reasons, therefore, 

 for concluding that at the end of the Ricardo post-Miocene cycle 

 of erosion there still existed a residual mountain range on the 

 site of the highest crests of the present Sierra Nevada. 



Latest Epoch op Faulting, not Affecting the Entire 

 Southern Sierra Front 



If one examines the stage of topography of the east flank of 

 the Sierra west and south of Owens Lake, as represented on the 

 Olancha topographic sheet of the United States Geological Sur- 

 vey, and compares it with the stage of topography of the east 

 flank south of Walker Pass on the Kernville topographic sheet, 

 one notes a remarkable difference. The eastern scarp of the 

 Sierra in the neighborhood of Owens Lake is very precipitous, 

 the base of the range approximates a straight line with no broad 

 re-entrants along the drainage courses, or shoulders projecting 

 out into the basin area between the drainage courses. All the 

 canons cutting into the east front of the range have deep, narrow, 

 steep-walled, and V-shaped courses. The topography of the east 

 front of the Sierra from Indian Wells northward into and 

 beyond Owens Valley is much more youthful than that of the 

 section of the range from Indian Wells southwestward to Jaw- 

 bone Canon. 



Looking into the Sierra from one of the lower summits in 

 the vicinity of Jawbone Canon one sees near the horizon line 

 a broad shallow, high-level valley corresponding in stage of 

 development with those opening out on the foot of the range 

 farther east. Put as this drainage course is traced down 



