396 



GEOLOGY. 



As the ice-lobe that lay in the Erie basin retreated, the crescentic 

 Lake Maumee at its end expanded, one horn extending eastward on 

 the southern border of the lobe, and the other northward on the north- 

 western border, until the latter found a pass along the south side of 



^ 



ih 



»- 





Jt)U& 



■:Z& 



&*? 





> ^ 



T* 



• J- -. ' " 2. - - •» • 







u-': N 





#?. .-' 



'A** 



%>> 





#> 



J 



M 



Fig. 516. — The beginnings of the Great Lakes. The ice still occupied the larger 

 parts of the present lake basins. (After Taylor and Leverett, U. S. Geol. Surv.) 



the Saginaw ice-lobe, lower than the Fort Wayne outlet. This pass was 

 the Imlay outlet. The escaping waters then skirted the edge of the 

 Saginaw ice-lobe to the valley of the Grand river, following which 

 they crossed the lower peninsula of Michigan, and joined Lake Chicago 

 (Fig. 517), the left horn of which had, by this time, reached thus far 

 north. This constituted the second stage of Lake Maumee. 



