THE GLACIAL LAKES 



grandeur of the scenic beauty in western New York, particu- 

 larly near Jonesville and in the Blue I lills. 



At the close of Lake Elkton time the ice had retreated 

 northward tar t'ni)ui;h so tii.u the Cjrcat Lakes began to shrink 

 into the Hniiis ot the ancient river basins and to assume some- 

 what their present appearance. In the Superior basin Lake 

 Duluth extended eastward to the highlands of Keweenaw 

 Peninsuhi and the Huron Mountains, and westward and 

 northward beyond Dulutii, Minnesota, and lort W'ilham 

 Ontario, but its outlet was still through the Bois Brule-St. 

 Croix River to the Mississippi. 



Lake Chicago had enlarged northward until it occupied 

 Green and Traverse bays. It received considerable drainage 

 from the ice fronts in the Northern and Southern peninsulas 

 of Michigan and continued to drain to the Mississippi. Lake 

 Saginaw had merged with Lake Likton; a large lake in the 

 Simcoe basin of Ontario was connected with Lake Elkton by 

 a stream flowing along the ice front; the western end of the 

 Ontario basin was occupied by the eastern part of Lake Elk- 

 ton, extending in long narrow bays around the Ontario ice 

 lobe. Overflow discharged eastward over high cataracts and 

 drained along the ice border past Syracuse and down the 

 Mohawk valley to the Hudson. This drainage channel is 

 known as the Syracuse outlet. 



The effect of lowering the outlet through the Syracuse 

 channel \vas to increase the power of the currents flowing 

 over the old submerged moraines which marked the former 

 positions of the ice front south of Port Huron and which 

 had acted as barriers holding up the waters in the Saginaw and 

 Huron basins. These moraines are south of Port Huron, at 

 Detroit, and near Trenton — soutliwest of Detroit. The 

 morainic material was easily cut tiirough by several streams, 



51 



UBRARY 



UNFVERsmr OF iiumxs 



Kf URBANA -CHAMPAIGN 



