THE GLACIAL LAKES 



lakes, and also the probable positions of the ice front as 

 marked by the terminal moraines made by the several lobes. 

 Glacial Lake Maumee (Figure 4) was curiously shaped, 

 with long narrow arms extending around the edge of the Erie 

 ice lobe and a funnel-Hke outlet southwestward to the Wabash 

 River. Along tiie bordering moraine are the lake beaches, 

 sloping eastward into the flat bottom of the old lake. The ice 

 front of that time is marked by the line of hills known as the 

 Defiance moraine (named from Defiance, Ohio), which 

 swings around the position marking the edge of the Erie lobe 

 from Ohio into Michigan. Where the lake bordered the ice 

 the moraine was deposited in the waters of the lake. 



The Second Stage of Lake Maumee 



When the ice retreated from the Defiance moraine, it 

 opened a northern outlet near Imlay City, Michigan, thirty- 

 five feet lower than the Fort Wayne outlet. The waters of 

 Lake Maumee then abandoned the Fort Wayne outlet and 

 flowed in an arc across the Thumb of Michigan, past Flint and 

 Durand, along the edge of the Saginaw ice lobe and into 

 Grand River. (Figure 5.) Before that time Grand River 

 probably had been only a trickling stream in a crease in the 

 moraine. The change in outlet started the second and lowest 

 stage of Lake Maumee, which lasted long enough for the lake 

 to build typical beaches and shore formations, as it had done 

 at the higher level. But from this time on the story of the 

 lakes becomes very complex. Retreats of the ice front opened 

 lower outlets and changed the direction of drainage discharge 

 from the lakes; re-advances of the ice raised the level of the 

 waters, closed older outlets and opened new ones. Almost 

 every oscillation of the ice front was of a duration long 

 enough for the lakes to produce their characteristic records. 

 By patient search many of the old strand lines have been lo- 

 cated, even though rising waters destroyed much of the 



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