PLEISTOCENE OF EUROPE, NORTH AFRICA, AND NORTH AMERICA 443 



2,000 to 3,000 feot higher than now; deep canons were eroded in the Sierra 

 Nevada and Coast ranges; this is the Sierra n Epoch, which corresponds to 

 the pre-GIacial or Ozarkian Epoch of the East. In the succeeding Glacial 

 times the Sierras were covered by a great ice sheet which poured its glaciers 

 dovra canons 6,000 or 7,000 feet above sea level. This indicates that in 

 the Glacial Epoch the climate of California was very similar to that which 



Fig. 192. — North polar view of the world showing existing outlines, and (dotted areas) eleva- 

 tion to the 200 fathom line, indicating the northern areas of migration in Pleistocene time. 



now prevails in the Olympic Peninsula of Washington, where glaciers de- 

 scend to a point 6,000 feet above sea level. The present climate of this 

 peninsula is cool and rainy, and the forests consist almost entirely of conifers. 

 During this period of elevation the Channel Islands (Santa Rosa) off the 

 coast of southern California were connected with the main land, allowing 

 the mammoths to make their way across on dry land.^ 



* Smith, Jas. Perrin, Salient Events in the Geologic History of California, Science, n.s., 

 Vol. XXX, no. 767, 1909, pp. 346-351. 



