DEFORMATIONAL LAKE BASINS 



119 



outlet, is determined by the relation between rainfall and evapora- 

 tion. A typical example is found in the extinct Lake Bonneville 

 (Gilbert-15), which extended along the western base of the 

 Wasatch range for 300 miles. Its surface covered 19,750 square 

 miles at the highest stage, and its hydrographic basin had an area 





Fig. 19. Sketch of Albert Lake, Oregon, a fault-basin lake. (After Russell.) 



of 52,000 square miles. By evaporation it has now been reduced 

 to a body of salt water which in 1850 was 1,750 square miles in 

 area, with a maximum depth of 36 feet— the Great Salt Lake of 

 Utah. Another example in the same region is the extinct Lake 

 Lahontan, which lay in what is now northwestern Nevada, with an 

 arm extending into California, and with a length of 260 miles. 



Fig. 20. Section through Lakes Tanganyika and Rukwa, from northeast to 

 southwest. Vertical scale exaggerated five times. (After Moore.) 



and enclosed an island 126 miles long and 50 miles broad. Most 

 of the valleys occupied by the arms of this lake are deserts now, 

 but some contain small lakes of more or less saline or alkaline 

 waters, but not of concentrated brines. (Russell-31.) What ap- 

 pears to have been an enormotis inland sea or lake of this type, 

 but beginning as a cut-off from the sea, occupied, according to 



