THK GLACIAL LAKES 



cent-shaped lake around the end of the Superior lohe, which 

 drained throui;h the old Lake Brule outlet to St. Croix River 

 and the Mississippi. Lake Ontonagon was lowered about 200 

 feet, and its bed became land, but narrow bays of Lake Duluth 

 extended a few miles up each of the tributaries of Ontonagon 

 River south of the Copper Range. 



Lake Elkton 



Powerful as were Lakes Warren, Chicago and Duluth, they 

 also gave way to lower lakes, as the ice once again retreated 

 and drew the lake waters down. Lowering was slow and halt- 

 ing, and at each halt the lake had time to make a beach. At 

 two such halts prominent beaches, the Grassmere and Elkton, 

 were built. During that period the waters of the Huron and 

 Erie basins were connected by a broad shallow strait across 

 the site of the St. Clair and Detroit rivers and Lake St. Clair. 

 As the lake level fell parts of the strait became so narrow that 

 the waters flowed through it with a river-like current across 

 the submerged Port Huron moraine, eleven miles south of 

 Port Huron, Michigan. This stream may be considered the 

 ancestral St. Clair River. Through it the waters of Lake 

 Saginaw were brought to the level of the next lake in the 

 Erie basin — glacial Lake Elkton (formerly named Lake 

 Lundy.)"" (Figure 10.) 



When the lakes settled to the Elkton level the Grand River 

 outlet was abandoned, because a lower outlet was uncovered 

 eastward through the Marcellus-Cedarvale channel which 

 crosses the hills southwest of Syracuse, New York. This out- 

 let passed over the Niagaran escarpment and was shifted west- 

 ward over it from place to place as the water level lowered. 

 The outlet stream falling over the escarpment made falls as 

 high and imposing as Niagara, and although little or no water 

 now descends (ner these "fossil" cataracts, they add to the 



•Dr. Frank Lcvcrctt chnriKcd the name of this lake fr<ini l.undy tn I'lkton in 19^9. 



49 



