Geography of Ohio 215 



had a direction transverse to the front of the ice. The ice with- 

 drawing down the slope of these divides, all of which inclined to 

 the north, allowed the local bodies of water to coalesce. In time 

 a lake paralleled the front of the ice, and had an outlet westward 

 through Fort Wayne, Indiana. The name, "Maumee," has been 

 given this ice front lake. 



Lake Maumee. Under the direction of the Ohio Geological 

 Survey, during the years 1869 to 71, G. K. Gilbert, in connection 

 w4th other investigations in northwestern Ohio, did the first w^ork 

 in mapping this lake, noting its beaches and other shore phe- 

 nomena. He mapped the morianic ridges also, thus determining 

 the outline of the Erie ice lobe, in front of which Lake Maumee 

 stood. 



The wasting of the glacier itself, with the accession of the drain- 

 age from the basin south, was so great that water ponded rapidly 

 in front of the ice sheet. The general trend of the shore of this 

 lake in Ohio was east-west; in Michigan, north-south; in form it 

 was saddle-shaped, resting against the Erie ice-lobe. After the 

 Fort Wayne outlet, now 735 feet above tide, was uncovered. Lake 

 Maumee continued its overflow in that direction till the ice had 

 retreated far enough to disclose, somewhere north or east, a place of 

 lower altitude; then a new overflow channel would be established. 

 This, however, did not occur till the ice sheet had withdrawn north- 

 ward in Michigan to the vicinity of Imlay, in Lapeer County. 

 This new overflow channel was revealed near the reentrant angle 

 betw^een the Erie and Saginaw bay lobes; its altitude is only 

 fifteen to twenty feet lower than the Fort Wayne channel. 



I have already explained (p. 195) how minor advances sometimes 

 characterize a general recessional movement of the ice. In con- 

 sequence of such oscillations, it is thought that the Fort Wayne 

 outlet was temporarily used for short periods even after the Imlay 

 channel had been uncovered. The overflow channels of ice-front 

 lakes, particularly w^hen near the ice itself, as was the case in the 

 reentrant between the Erie and Saginaw lobes, carried great 

 quantities of water, sometimes laden with cutting tools. For this 

 reason the channels themselves were degraded, and, as they were 

 cut down, the general level of the lake declined. At first, it is 

 probable that the altitude of the Imlay and Fort Wayne channels 

 did not differ much. If the Imlay outlet w^ere in use a consider- 

 able period of time, this lower stage of Lake Maumee should be 



