218 future's 



some miles west of its present channel through 

 the high hills in the region of Baraboo. The 

 hills on each side of Devil's Lake are very pre- 

 cipitous and are formed almost entirely of 

 rocks. The river at that point passed between 

 two of these hills. When the ice flowed down 

 it surrounded these hills, yet did not sweep 

 over their tops, but left great piles of glacial 

 drift, both at the points where the river chan- 

 nel entered the hills and where it emerges 

 from them. The channel between the hills 

 was protected and not filled with the debris. 

 Therefore a deep basin was left, which is kept 

 filled by the watershed furnished by the sur- 

 rounding hills. This lake recedes many feet 

 during the summer, but it is again filled up 

 by the rains and snows of winter. There is no 

 considerable stream either flowing into or out 

 from it. It is a lake formed by the glaciers, 

 but in a different way from those in the gravel 

 deposits at other parts of southern Wisconsin 

 and northern Illinois. 



There are hundreds and perhaps thousands 

 of lakes that have been formed in one way or 

 another through the power of glacial action. 

 These smaller inland lakes, so many of which 

 are seen in northern Illinois, southern Wis- 

 consin, and Minnesota, are due almost entirely 

 to the great deposits of glacial drift that have 

 been transported with the ice. Wherever 

 these " kettle holes " are found large bodies of 



