Science, Geology and Physics 



existing conditions, its volume would have been three- fourteenths *90i 

 of the present flow. This is less than the volume of the water 

 pouring over the American fall, which recedes 0.64 of a foot 

 annually. This stream may be conceived to wear away the rock 

 at the rate of six inches annually. If so, it would have required 

 7,800 years for the formation of the gorge of the whirlpool 

 rapids. 



The Eddy basin seems to have been worn by the normal 

 Niagara. With the same rate as has been given for the first 

 section, only 375 years would be required to erode this distance 

 of 1 ,500 feet. The whirlpool belongs to the St. David's epoch, 

 and will be considered in another connection. 



The Cove section, or the part from the whirlpool to the nar- 

 rows at Foster's Island, is 3,750 feet long. No one imagines 

 the rate of the recession for this section to be different from that 

 first named, as the width of the gorge and the depth of the water 

 are the same. This would have required 937 years for its 

 excavation. 



Professor Spencer has calculated the age of the lower section 

 of the gorge from Lewiston to Foster's Island to be 1 7,200 

 years, upon the assumption that the conditions would be those 

 of the American falls. But measurements of the breadth below 

 the Cove section give an average of width of the top of the gorge, 

 fully equal to that of the upper gorge as far as to the Catholic 

 College, 5,754 feet, while the other part, 8,448 feet, may for 

 convenience be comparable to the American falls. Calculations 

 upon these bases give 1 ,438 years for the upper part, and 5,406 

 years for the lower, a total of 6,844 years. 



The section from the beginning of the whirlpool to the edge 

 of the escarpment, near St. David's, is about three miles in 

 length. Its erosion was effected before the last ice-epoch, accord- 

 ing to our interpretation, and some might say pre-glacial. It 

 would appear that the volume of the water passing through was 

 fully equal to that of the present epoch, and may have been 

 derived from the same sources. At the rate of recession adopted 

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