112 LIFE OF THE PLEISTOCENE 



E. GREEN BAY BASIN 



The history of this region is not yet fully worked out but is believed to be 

 as follows: "there was first a lake that discharged from the district south of 

 Lake Winnebago southward past Horicon into Rock River. This lake per- 

 sisted until the ice which formed the moraine at the head of Lake Winnebago 

 had receded far enough northward to open a passage westward from Oshkosh 

 to the head water part of Fox River. Then the discharge was shifted past 

 Portage to the Wisconsin Valley. Later, when the melting of the ice cleared 

 the Green Bay peninsula the waters lowered to the Lake Winnebago level and 

 to a lake in the Green Bay basin by discharging eastward into Lake Chicago. " 3 

 (Plates XLVIII, XLIX.) 



F. HURON-ERIE BASIN 



This basin lies south of Saginaw Bay and is continuous with the Erie basin 

 across the Canadian peninsula. Converging ice currents became confluent 

 in this basin and formed the Huron-Erie ice lobe. This basin has had a very 

 complicated history, changing in outline as different outlets were uncovered, 

 one after another, as the ice receded. 4 



Lake Maumee 



The Erie lobe formed several small lakes on its margin which finally united 

 to form Lake Maumee, at the southwest end of the basin, which found an out- 

 let past Fort Wayne, Indiana, to the Wabash River; this is known as the Fort 

 Wayne outlet (Plate XLVIII). Lake Maumee continued during three stages, 

 during which the level of the water fell 30 feet and the outlet changed several 

 times. The Fort Wayne outlet formed the first stage (altitude 790 feet above 

 tide). As the ice melted back, the lake expanded over the low country, east 

 and north, finding an outlet at Imlay, Michigan, into the Grand River, and 

 thence into Lake Chicago. This is known as the second stage and is 10 feet 

 lower than the first stage (780 feet). Further recession of the ice border 

 uncovered lower outlets, one near Ubly and one farther north, and the Imlay out- 

 'et was abandoned, as was also the outlet by way of Fort Wayne into the Wa- 

 bash River. This formed the third stage, the level of the lake being 760 feet. 



G. HURON-ERIE-ONTARIO BASIN 



1 . Lake A rkona 



For some reason, not yet well understood, the lake waters were drawn down 

 to a much lower level (altitude 710-694 feet). This lake filled much of the 

 Saginaw basin, and is also believed to have extended as far east as Alden, New 



3 Taylor, An. Rep. Smith. Inst., 1912, p. 314. 



4 Leverett, 12th An. Rep. Mich. Acad. Sci., page 30; Taylor, op. cit. 



