Science, Geology and Physics 



The Upper Section. 1 ® 01 



Hitchcock 



Between the falls and the railroad bridges, a distance of two 

 and one-fourth miles, the interpretation of the history is easy. 

 The gorge is uniformly of great width and depth, 1 ,300 feet in 

 width and with the ordinary depth of 160 feet for the river. 

 At the very cataract the bottom of the river is 100 feet lower 

 than the level of Lake Ontario. The water moves slowly, fall- 

 ing about seven feet to the mile. The rocks vary but little in this 

 section. All agree that the conditions determining the formation 

 of this gorge are practically the same with those now prevailing; 

 and, consequently, the only change in the scenery has been the 

 position of the cataract. Having the same volume as now, the 

 levels of all the upper lakes have not varied appreciably. With- 

 out doubt, during this episode, the falls have been viewed by 

 the aborigines of our continent as they carried their canoes and 

 cargoes from lake to lake. 



The increase in the volume of water is supposed to have been 

 occasioned by the rising of the land at North Bay; damming the 

 water and compelling it to wear its channel through Lake St. 

 Clair to Lake Erie. When the rush began, it bared many acres 

 of rock on both sides of the river, leaving various denuded tracts, 

 as the flat two miles in length, south of the steel arch bridge, on 

 the Canadian side, and a very narrow strip on the American 

 side, reaching as low as to the whirlpool, give evidence. These 

 flats are like the bed of Niagara above the rapids, if the water 

 were removed and vegetation had gained a footing. Because 

 of the presence of these old river beds where the Johnson ridge 

 crosses the gorge, it seems to us that it furnishes no obstacle to 

 the free passage of the water. This ridge is an anticlinal swell- 

 ing in the strata, but had been broken down by early erosion, so 

 that really no greater mass of limestone has been excavated here 

 than elsewhere in this section. 



Goat Island rose higher than the water on either side, and, 

 therefore, dividing the stream into unequal portions. Its former 



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