49 



detail may be seen at that point. Instead of finding a 

 sheer descent from the brink, the heavy water at the 

 apex strikes a rock shelf, estimated to be about 40 feet 

 (12 m.) below the top, from which it rebounds whitened 

 and foamy before making the final plunge. The shelf 

 must be of large proportions and has existed for many 

 years. Before the recent improvements for power devel- 

 opment in Queen Victoria park, a thin water sheet like 

 that which flows over the Goat Island shelf fell over the 

 cliff where the parapet now stands and the edge of the water 

 on the brink was then 415 feet (126-5 m nearer Table 

 Rock house than it is now. The total length of the crest 

 line was then about 2,950 feet (900 m.). 



For a nominal fee visitors may descend by an elevator 

 to a tunnel leading to a point under the nearer part of the 

 falls, about at the edge of the heavy water, where a window- 

 like opening looking out towards the falling water has 

 been made. Nothing can be seen except a diffused 

 varying light that comes through the water. The thunder- 

 ous roar of the water is deafening. The trip is worth 

 making for the impression of titanic power which this 

 sound produces and for the realization of one's nearness 

 to the great cataract. 



The Recession of Horseshoe Fall. — When it is 

 understood that the gorge extending for nearly seven 

 miles (11-3 km.) from the escarpment at Lewiston up to 

 the Horseshoe fall, was made by the Niagara river itself 

 since the disappearance of the last ice sheet, it becomes 

 a matter of much interest to know at what rate or rates 

 the gorge was lengthened and how long a time has been 

 involved. Those who have studied this problem carefully 

 have reached different results, that varied chiefly according 

 to the authors' conceptions of the history of the Niagara 

 river and of the dependence of that history upon the 

 Great Lakes history. Many other variable factors enter in 

 but no other approaches in importance to the relation 

 of Niagara to the great lakes. If the gorge were exactly 

 seven miles (11-3 km.) long and the rate of recession of 

 the cataract had averaged exactly five feet (1-5 m.) per 

 annum, it would be easy to say that it has been 7,392 

 years since the falls began at Queenston. Those who 

 have held strongly to the conclusion that the duration of 

 Niagara has been no more than 7,000 to 10,000 years 

 seem to have relied upon a simple calculation of this kind. 



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