40 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST. 



Sierra. The main glacier came down from the vicinity of Kearsarge Moun- 

 tain along the route of the present trail. About six miles from the summit, 

 here over 12,000 feet high, it was joined by a side-glacier coming in from 

 Mount Brewer on the south. Between these two ice-masses a moraine was 

 formed, of Avhich the present appearance is that of a vast embankment of 

 loose boulders and angular fragments of rock, piled up with the steepest 

 slope on which such materials will lie without sliding, the upper edge of the 

 western side being elevated from 1,400 to 1,500 feet above the bottom of 

 the valley. On the eastern side, or that nearest to Mount Brewer, is a de- 

 pression having a depth of from 400 to 500 feet. On the opposite or west- 

 ern side of the valley is the corresponding lateral moraine, at a distance of 

 about a mile and a half, having nearly the same altitude as the other one, 

 but being considerably smaller. The tops of these moraines, especially 

 of the eastern one, are quite smooth, and are covered with boulders, and 

 they have a gentle inclination up the valley, looking in the distance as 

 regular as railroad embankments.* To ascend or descend the sides of these 

 moraines with animals was a very difficult task ; to travel along on their 

 crest, comparatively easy. The former tliickness of the glacier at this point, 

 as estimated by Professor Brewer, must have been at least 1,.300 or 1,400 

 feet; a mile farther up the valley he estimated it at not less than 1,800 feet. 

 The valley between the two moraines is pretty free from detritus, and beauti- 

 fully scored and polished. 



On the eastern slope of the main range of the Sierra, opposite the head 

 of Kern and King's i-ivers, glaciers undoubtedly once existed ; but they did 

 not descend into Owen's Valley, or even approach it within considerable dis- 

 tance. The Hanks of the range between Owen's Lake and the Fish Springs 

 volcanic group are covered up to a jjerpendicular height of over 2,000 feet 

 with the " wash " previously described, and commonly called the sage-brush 

 slope. There are no data in the writer's possession from which it can be 

 clearly made out how much the glaciers, at the time of their greatest exten- 

 sion, lacked of reaching this belt of detritus. Explorations made in 1872 

 along the flanks of the range rendered it evident that the ice could not here 

 have descended as low as a line 7,000 feet above the sea-level ; but there 

 was too much snow on the mountains at that time, the month being May, to 

 obtain any satisfoctory evidence on this point. 



The valleys occupied Ijy the various branches of the Upper San Joaquin 



 See Geology of Califoniia, Vol. I. p. 379, for a section across these moraines. 



