NE-SAW-JE-WO N 



that the river has accompHshed little gorge-cutting and little 

 destruction of the rapids. 



The Modern Great Lakes 



When all the waters had ceased to flow through the North 

 Bay outlet and all finally poured southward to Lake 

 Erie, the present stage of the Great Lakes was begun. These 

 lakes, like their glacial ancestors, are building beaches, mak- 

 ing shore cliffs, cutting caves and arches in rocky headlands, 

 and deepening fjords — as along Isle Royale and Les Cheneaux. 

 In other places they are straightening shores by building bars 

 and spits across the bays, creating — as did Lake Nipissing 

 along the Lake Michigan coast — small lakes barred from the 

 large lake by dune-capped sand bars. Sands from their shores 

 are being piled by the wind high in dunes. Dunes along Lake 

 Michigan are as high as, if not the highest dunes in the world. 

 In places like the Sleeping Bear — on the Point of that name 

 on the northwestern coast of the Southern Peninsula of Michi- 

 gan — the dunes are perched atop the bordering moraine; in 

 other places they bury the Algonquin and Nipissing shores. 

 Down-cutting of the outlets continues, so that beaches lower 

 than the Nipissing have been made by the modern lakes. One 

 of these beaches, which is fairly strong and can be traced 

 around the lakes, is called the Algoma beach, from the place 

 where it was first noticed on North Channel of Lake Huron. 



The connecting rivers of the Great Lakes also have had an 

 interesting and complicated history, as they developed with 

 the changing lakes. In order of age (in the present arrange- 

 ment of the lake-river system) these rivers are St. Clair, De- 

 troit, Niagara, Nipigon, St. Lawrence and St. Mary's. Nipi- 

 gon River is the largest tributary of Lake Superior and in its 

 lower course flows across the dry bed of old Lake Nipigon, 

 once the most northerly bay of Lake Algonquin. So many 



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