﻿Jan., 1857.] 



ELLIOTT SOCIETY. 



95 



the causes that may have operated to produce it. The following 

 present themselves to me, and most probably the effect may be due 

 to the joint action of two or more of them. 



1st. The times of action of each Fall may have been unequal; 

 that is, there may have existed across the outlet A D, a natural 

 dam, (of which the small islands still existing maybe the remains,) 

 which gave way sometime after the main Fall had passed the point 

 D, permitting the American Cataract then to begin its fall. 



2d. The average volume of water passing over a linear yard of 

 the brink of each Fall, may be unequal. 



3d. There may be an unequal facility of abruption presented by 

 the rocky strata at each Fall, or in the two different directions in 

 which the Falls have respectively receded. 



4th. The direction in which the strata dip may have some influ- 

 ence in promoting or retarding the recess of the one or the other Fall. 



The first of these hypothesis having but little probability in its 

 favor, and presenting no hold for discussion, we may be permitted 

 to pass it by, for the present, at least until the others are ex- 

 amined. 



Before proceeding to their discussion, we must call attention to 

 a very remarkable circumstance, whose value in the discussion of 

 the past and future condition of the Falls does not appear to have 

 been insisted upon, or even noticed. It is this: That the four points, 

 A, the northern extremity of the American Fall, F, the vertex of 

 the Canada Fall, and D and G, the two angles of Goat Island, are 

 nearly in a right line, parallel to the general course of the gorge 

 below, and at right angles to the general direction A K of the brink 

 of the Fall. It would appear, therefore, that the Fall which had 

 excavated the gorge below A K, in a certain direction, had con- 

 tinued this excavation, in the same direction, uninfluenced by the 

 presence and action of the American Fall, (except by the abstrac- 

 tion of so much water,) and had now assumed the position F H. 

 With respect to its future condition the Canadian Fall may be re- 

 garded as consisting of two portions, the one F H corresponding, 

 in its relations to the strata beneath, to the original Fall A K, and 

 the other F G, in the like relations, corresponding to the American 

 Fall. If this view be correct, the general course of the Canadian 

 Fall will be towards the point I, and the formation, finally, of a 

 Fall along the line G I, whose recession will be slower than 

 formerly. 



Now, on the view above taken, that the main Fall has cut its way 



