igooi.] On the Ancient Drainage at Niagara Falls. 



HYPOTHESIS OF THE MODE OF GORGE FORMATION AND CHARACTER 

 OF THE FLOOR OF THE GORGE. 



The water wears a large pit in the shale underlying the Niagara 

 limestone, leaving it projecting until, unable to support its own weight, 

 it breaks off and falls into the water. The Clinton limestone is under- 

 mined in the same way. After falling, these great masses of rock in 

 front of the centre of the Canadian fall, are used as pestles by the 

 tremendous power of the water, ground against one another and against 

 the floor of the stream, until a great hole or basin is worn out down 

 stream from the falls. 



As the water gets down stream further from the fall, it loses energy, 

 and finally a point is reached at which it can no longer move 

 the larger rocks. At this place they are deposited in what formerly 

 was the floor of the basin, and over these larger pieces smaller ones are 

 deposited successively on account of the decreasing power of the water 

 until, at some distance from the stream, the deposit attains a maximum 

 height, acting there as a dam, over which the accumulated water flows. 

 This water, by erosion, wears off the top of the old deposit, so that the 

 position of the shallow dam, of the basin in front of the falls, and of the 

 falls itself, is gradually advancing up stream, leaving behind it, in the 

 bed of the river, the accumulated mass of fallen blocks. 



This is the way in which the gorge has been made, at least from 

 Foster's Flats. Below this, there may be part of the stream flowing on 

 a bed of rock in place, as there was a time in the history of the Falls in 

 which there were three separate cascades, and this condition would 

 destroy the power of the water to dig out a deep hole as described 

 above. 



The borings made by the Michigan Central Railway to test the 

 foundations of the Cantilever bridge afford a remarkable confirmation of 

 this hypothesis. For 150 feet below the waterline, or nearly 70 feet 

 below the deepest part of the river at this point, before striking rock in 

 place, they bored down through clay and boulders. The rock they 

 found was the red shale of the Medina, which, according to the above 

 hypothesis, was the bottom of the deepest part of the basin worn by the 

 Falls when passing this point. 



In his report, the engineer called some layers, lime rock, sandstone, 

 bastard lime rock, etc. Thinking these layers might represent remains 



