THE WORK OF RUNNING WATER 



81 



Fig. 81. A hogback, Colorado City, Colo. 



Fig. 82. Fig. 83. 



Fig. 82. Chesapeake Bay and its surroundings. The bay is a drowned river 



valley, and the lower ends of its tributary valleys are also drowned. 

 Fig. 83. The drainage of the region about Chesapeake Bay, somewhat as 



it would have been but for drowning. 



