GEOL.-VOL. I.] TURNER— ORIGIN OF YOSEMITR VALLEY. 319 



formerly occupied the canyon, while it extended to the 

 west or up-stream base of the cliffs, seems never to have 

 attained any considerable thickness at this point. Had 

 Sawmill Creek been a river, a Yosemite would have 

 resulted. 



Hetch Hetchy Valley on the Tuolumne River, with an 

 altitude of 3,660 feet, has already been mentioned. If 

 a similar valley exists on the San Joaquin River, the next 

 stream south of the Merced, it has not yet been described, 

 but on the Middle Fork of the King's River is Tehipite 

 Valley, with an altitude of about 4,200 feet. It is sur- 

 rounded by high cliffs and there is here also a magnificent 

 dome, a view of which is reproduced in a paper on Tehipite 

 Valley by J. M. Stillman.^ According to Mr. J. N. Le 

 Conte, this dome rises 3,000 feet above the valley. On the 

 South Fork of King's River, situated relatively like the val- 

 leys above noted, is the Grand Canyon of King's River. 

 No one except those holding Muir's views can doubt that 

 water is the main agent in cutting the deep canyons of the 

 range below the limit of glacial ice. This would allow river 

 action to form that part of the Merced canyon west of Big 

 Meadow, and thus the river, without the aid of ice or of 

 drop-faulting, has cut a canyon 3,500 feet deep. As pre- 

 viously suggested, it is difficult to see how the river, having 

 in its lower reaches dug out a deep canyon, should sud- 

 denly lose this erosive power on reaching the glaciated 

 region, for although the ice sheet is represented as protect- 

 ing the land from extensive erosion, it has been shown that 

 the ice probably did not occupy the glaciated zone during 

 all of early Pleistocene time. Much more natural is it to 

 suppose that the rivers have in the main formed the canyons 

 they occupy from their source to the Great Valley. 



That some faulting has occurred along the sheeted or 

 jointed zones of granite about the Yosemite is probable, 

 but it is thought that this has resulted rather in a more thor- 

 ough shearing of the granite than in the dropping down of 



1 Sierra Club Bull., Vol. II, 1S97, Plate VII. 



