SHASTA KOUTE — SEATTLE TO SAN FRANCISCO. 



11 



Lake W 



■» 



beautiful 



eastern 



miles lonof and 2 to 5 miles 



Excursions from 



Seattle, 



Snoqualmie Falls (PL III) i; 

 wide and is well wortli seeing. 



entirely surrounded by glacial drift. Small steamers 

 that ply to and fro on the lake afford fine views of 

 the Cascade Range. 



may 



during ■vrUch the ice is believed to have 

 largely or wholly melted away. Tliere is 

 evidence of at least four of these distinct 

 stages of glaciation, and the la^t of these 

 is known as the Wisconsin stage. 



tended southward from British Columbia 

 into the Puget Sound basin, (See Pi. I.) 

 The name Vashon, from the large island 

 between Seattle and Tacoma, hag been 

 applied by geologists to this ice lobe, tlie 



Figure 1— Map of North America showing the area covered by the Pleistocene ice sheet at its maximum 



eiitension and the three main centers of ice accumiilation. 



At a time wluch probably corresponds 

 to the Wisconsin stage of glaciation east of 

 the Rocky Mountains the moim tains of 

 Washington were largely covered with ice, 

 and a lobe of the Cordilleran ice sheet ex- 



last of the Puget Sound glaciers, and to 



wi 



This glacier is believed to have attained 

 a thickness of about 2,500 feet. Th 



eice 



epressions 



