Niagara Falls 



1901 southeast direction, corresponding to the course of the gorge itself, 

 but differing fully seventy degrees from that observed upon the 

 surface of the plateau. The same course has been noted at 

 Thorold, and is quite common near the Dundas Valley; so that 

 it is not necessarily a local deflection produced by the crowding 

 of the ice through the St. David's Channel ; it may result from the 

 movement that blocked the Erigan gorge, though it seems better 

 to refer it to the later epoch. (5) The depth of the Niagara 

 River in the whirlpool and just below, in the lower gorge, are 

 best explained by supposing the existence of an earlier St. David's 

 Channel. The water is 150 feet deep in the whirlpool, is very 

 shallow at the outlet, making a shelf there, while the normal 

 great depth is renewed below. Deep excavations are made by a 

 cataract; shallow ones, by rapids. When the river had worn 

 back nearly to the whirlpool, there would be only a narrow rim 

 separating the cataract from the ponded water above. The 

 pressure of the water above would knock the wall down laterally, 

 and thus there would have been no pounding of the lower layers 

 by the cataract. If the wearing action had been effected by 

 falling water continuously around the great bend, the depth 

 would have been uniform, whereas now there is a shallow river. 

 Hence, it is evident that the whirlpool pit existed before the 

 origination of the lower gorge. 



Granting the exercise of St. David's Channel the following 

 events seem to have been necessitated: (1) A Niagara River, 

 fully equal in dimensions to the present stream, flowed from the 

 whirlpool to the edge of the escarpment near St. David's and 

 thence to Lake Ontario. A cataract commenced at the cliff and 

 cut its way back the entire distance of three miles. As intimated 

 above, we can understand that sufficient water came down the 

 Erigan river to accomplish this result; and, therefore, it is not 

 necessary to say that the upper great lakes contributed their share, 

 as now, to swell the stream; yet they may have done so. (2) 

 Frigid conditions brought on a third ice sheet [Labrador] which 

 pressed against the edge of the bluff, broadened the mouth of 



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