﻿Jan., 1857.] 



ELLIOTT SOCIETY". 



93 



its majestic fall over the bluffs at Lewiston, and during which it 

 cut the wonderful gorge or chasm, at whose head it now continues 

 to exercise its resistless power. Several writers have endeavored 

 to form an approximate determination of this interval from the rate 

 at which the Falls recede. This rate has been variously estimated 

 from a yard or more to a foot per annum, and as the length of the 

 chasm is about 7 miles, or 35,000 feet, the length of the resulting 

 interval has varied from 10,000 to 35,000 years. This last esti- 

 mate given by Sir Charles Lyell, (Travels in N. Amer. 1845, voL 

 I., p. 27,) has apparently been adopted by some writers as an es- 

 tablished fact. The fact of recession is evident, the interval is 

 undoubtedly immense, but no one can yet pretend to have data 

 sufficiently accurate to attempt to estimate its length even approxi- 

 mately. 



In the third volume of the Bulletin de la Societe des Sciences 

 Naturelles de Neufchatel, M. Desor endeavors to correct the last 

 estimate given above. He estimates at 40 yards, the utmost 

 amount of retreat of the American Fall from the straight line join- 

 ing the banks of the chasm above and below the Fall, and says, 

 that if we suppose the American Cataract to have begun its fall at 

 no earlier date than the time of Hennepin, (who mentions its exist- 

 ence in 1678, and gives a figure of it,) we shall have an average 

 retreat of less than a foot per annum. If, then, he proceeds, we 

 regard the great probability that the American Fall originated at a 

 date vastly more remote, the annual regress is a mere fraction of a 

 foot, and the elapsed interval must be reckoned rather by hundreds 

 of thousands of years! 



Now, I cannot assent to his applying to the Canada Fall the 

 result drawn from the American Fall, since he omits to take into 

 consideration the very different rate of recession of the two Falls. 

 If we assume, what is generally granted, that the gorge or chasm 

 from the bluffs at Lewiston to the present position of the Canada 

 Falls, has been excavated by the action of the Falls themselves, then 

 there must have been a period anterior to the division of the Falls into 

 two as at present, when there was but a single fall extending from A 

 to K (woodcut page 92) just below the American Fall, whose brink 

 was along some irregularly curved line as A B K, resembling that 

 of the Canada Falls at present, or else along some irregular line 

 as A C K approximating to the straight line joining A K, resem- 

 bling, in this particular, the American Fall. Then, if we assume 

 that the river or portion of the main stream now forming the Ame- 



