Niagara Falls 



1908 j n tne mos t anc J en t system of which we can obtain an approxi- 



mately definite knowledge, Lake Huron was not more than half 

 its present size, while Georgian Bay formed the main body, con- 

 necting with Huron by a narrow strait. Michigan and Superior 

 occupied about their present limits, but were connected with 

 Huron by rivers rather than short straits; Erie occupied only a 

 fraction of its present position, having no connection with Huron. 

 The waters of the upper lakes were doubtless discharged from the 

 eastern end of Georgian Bay, which then included Lake Nipis- 

 sing, by way of the Ottawa River, into the St. Lawrence. Thus 

 the Niagara was deprived of about seven-eighths of its present 

 drainage area, and consequently was totally unlike its present 

 self. There is some indication that there may have been an 

 outlet from Georgian Bay by a more southerly route, namely, 

 the Trent River. If this were so, the northern route must have 

 been blocked by the ice, since the Trent Pass is much higher than 

 the one leading from Lake Nipissing, by way of the Ottawa. 

 These are some of the possibilities which must be taken into 

 consideration before any sure calculation can be made as to the 

 age of the Falls, for there must have been an epoch in the history 

 of the river, were it short or long, during which it carried only a 

 very small fraction of the waters which it bears at present. 



Let us turn again to the gorge of the river itself. We have 

 noted the similarity of structure of its two sides. This similarity 

 is continuous throughout except at about half-way from Queens- 

 ton to the Falls, where the river makes a turn in its course of 

 almost ninety degrees. On the outside of this angle is the only 

 place in the whole course where the material of the cliff changes. 

 Here there is a break in the solid rock of the bank, which is 

 filled with loose rock and gravel. This rift, to whatever it may 

 be due, is of pre-glacial origin, for it is filled with the same 

 material, the glacial drift, which covers the whole region. The 

 cliff along Lake Ontario also presents very few breaks; but a 

 few miles to the west of Queenston at St. Davids a broad gap 

 is found in the otherwise unbroken wall. This gap is also filled 

 with glacial drift. On its first discovery it was supposed to be 



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