180 THE ICE AGE IN NORTH AMERICA. 



The ancient area of glaciers in the Sierra Nevada Mount- 

 ains was chiefly confined to the western slope, and was most 

 remarkable in Tulare, Fresno, Mariposa, and Tuolumne coun- 

 ties, California, where, as we have seen, glaciers still continue 

 to exist. There are abundant marks of these ancient ice- 

 streams in the upper valleys of Kings, San Joaquin, Merced, 

 and Tuolumne Rivers. In the Tuolumne the glaciers were in 

 some places several miles wide and twelve hundred feet deep, 

 and extended as much as forty miles down the valley. Gla- 

 ciers likewise filled the Yosemite Yalley on the Merced 

 River. It is a mistake, however, according to Whitney, to 

 suppose that the Yosemite was formed, or indeed greatly 

 modified, by glacial action.* The vertical walls and the rect- 

 angular recesses are such as to indicate the action of disrupt- 

 ive rather than erosive agencies in their formation. 



The north-and-south valley between the Cascade Mount- 

 ains and the Coast range, in the State of Washington, is about 

 one hundred miles wide. The northern half of this is pene- 

 trated by the innumerable channels and inlets of Puget 

 Sound, which extends from Port Townsend south about 

 eighty miles to the parallel of Mount Tacoma. The Olym- 

 pian Mountains to the west rise to a height of about ten 

 thousand feet, as does Mount Baker in the Cascade Range to 

 the northeast. The shores and islands of Puget Sound have 

 every appearance of being portions of a vast terminal^ mo- 

 raine. They rise from fifty to two hundred feet above tide, 

 and present a mixture of that stratified and unstratified ma- 

 terial characteristic of the terminal accumulations of a great 

 glacier. No rock in place appears anywhere about the sound. 

 Bowlders of light-colored granite and of volcanic rocks are 

 indiscriminately scattered over the surface and imbedded in 

 the soil. One of these bowlders, near Seattle, two hundred 

 feet above the sound, measures twenty feet in diameter, and 

 twelve feet out of ground. The channels of the sound and 



- "The Yosemite Guide-Book," p. 83. See also the opinion of Mr. Russell 

 given near the close of Chapter X. 



