332 



EARTH FEATURES AND THEIR MEANING 



Chicago has thus the opportunity of observing first the beaches 

 of the former lake, and then the several channels which were 

 joined in the main outlet at the station of Sag (plate 20 A). 



In this stage of our history Lake Maumee pushed a shrunk 

 arm up past the site of Ypsilanti in Michigan (Fig. 361), the well- 

 marked beach being found on Summit Street opposite the State 

 Normal College. The Huron River, which in the first lake stage 



-X / / 



FIG. 361. Outline map of the later Lake Maumee and of its "Imlay outlet" to 

 Lake Chicago (after Leverett). 



had followed the valley now occupied by the Raisin River south- 

 ward into Indiana, now discharged directly into a bay upon this 

 arm of Lake Maumee, and so formed a delta at Ann Arbor. 



Lakes Arkona and Whittlesey. The ice front in the Huron- 

 Erie basin now retired so far that the impounded waters, instead 

 of following the more direct " Imlay outlet " to the Grand, passed 

 at a lower level completely around " the thumb " of Michigan 

 into the Saginaw basin. Meanwhile a crescent-shaped lake had 

 developed in that basin, so that now the waters of the Maumee 

 basin were joined to those in the Saginaw basin as a common 

 lake, just as the lowering of the waters in Glen Roy caused a 

 union with those of Glen Glaster in the example cited for illus- 



