614 



THE PLEISTOCENE PERIOD 



The southerly lobes of the complex body of ice crossed the boundary 

 of Canada into the United States. The plains of Alaska seem to 

 have been largely free from glaciation even when the waters of the 



Fig. 504. Sketch-map showing the North American area covered by ice at the 

 stage of maximum glaciation. 



Ohio and the Missouri, 2,000 miles farther south, were being turned 

 from their courses by the ice-sheets. 



South of the more or less continuous Cordilleran glaciation of the 

 north, local glaciers were widely distributed in the western moun- 

 tains, even down to New Mexico, Arizona, and southern California. 



