SIGNS OF PAST GLAGIATION. 



55 



stirring it from its position. But the vast area which is 

 marked in our map as having been covered with ice dur- 

 ing the Glacial period is characterised by deep and exten- 



'WSk 



k&* 



l..... _ 



Fig. 21.— Typical section of till in Seattle. Washington State, about two hundred 

 feet above Puget Sound. This is on the height between the sound and Lake 

 Washington. 



