224 



relative amount of 

 time which has elapsed 

 since the glaciers 

 melted away. 



Fiords. Where 

 thick glaciers push into 

 the sea through nar- 

 row bays, they may 

 scour the bay bottoms 

 much deeper, and at 

 the same time wear the 

 bay heads back into 

 the mainland. Where 

 ancient glaciers have 

 disappeared from such 

 bays, the sea has en- 

 tered to form long, 

 narrow, steep-walled 

 embayments, called 

 fiords (Figs. 242 and 

 243). Typical fiords 

 abound along the 

 Norwegian, Alaskan (Fig. 244), and certain other high-lati- 

 tude coasts. In most cases their depth is due partly to sub- 

 mergence of the coast. Many islands fringe these shores, 

 representing for the most part higher 

 land whose lower surroundings were 

 drowned. 



FIG. 238. Lakes of glacial origin in a moun- 

 tain valley. The nearest lake is in an ice- 

 scoured rock basin ; the others are held in 

 by drift. Note the U-shaped cross section 

 of the valley in the middle distance. Piney 

 Creek Valley, Bighorn Mountains. (Trow- 

 bridge.) 



Fro. 240. Section of a lake behind a 

 barrier of drift. 



Fro. 239. Section of- 

 a lake lying in an ice- 

 scoured rock basin. 



Which way did the 

 glacier move which 

 formed this basin ? 



