304 



THE ICE AGE IN NORTH AMERICA. 



Thus, since the elevation of Lake Erie is only 373 feet above 

 tide, the rock bottom of the Cuyahoga River, though 700 miles 

 inland, is now nearly at sea level. Newberry also discovered 

 that Grand and Rocky rivers flow over deeply buried 

 channels. In the case of Rocky River, Dr. D. T. Gould has 



Fig. 94.— Section across the valley of the Cuyahoga River, twenty miles above its mouth 



(Claypole.) 



traced the buried channel southward for a distance of nearly 

 thirty miles, or into its upper waters in Medina county. This 

 he has done by collecting the record of wells along the route, 

 and by noting various places where the present stream crosses 

 the old bed, passing out of rocky banks for a short distance, 

 and running through clay banks and over a clay bottom to 

 enter its new channel again between rocky walls. 



Professor Spencer has also shown, with great probability, 

 what was the preglacial line of drainage through which the 

 waters, both of Lake Huron and of Lake Erie, flowed to enter 

 Lake Ontario on their way to the sea. The line, as he first 

 thought, passes out of Lake Huron through the valley of the 

 Au Sable, crossing the Thomas River near London, in Canada, 

 and entering the basin of Lake Erie a little east of Port Stan- 

 ley. Thence, after passing around Long Point and Island, it 

 bends northward through the valley of Grand River, and 

 enters Lake Ontario at its extreme western point.* From 

 later information, furnished me by letter, it appears that Pro- 

 fessor Spencer is inclined now to make the connection be- 

 tween Lake Huron and Lake Ontario direct, passing through 

 Georgian Bay, and reaching Ontario in the vicinity of Toron- 



* " Second Geological Survey of Pennsylvania," Q 4 , pp. 35*7-406. 



