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I 
R. Bakewell on the Fails of Niagara. 87 
two yards the distance through which is flowing every minute the 
drainage of four great lakes, covering an area of about 135,000 
Square miles. The waters escape at the northern extremity of 
Lake Erie through a channel (as stated by Mr. Allen from meas- 
urements by Mr. KE. R. Blackwell) 1,700 feet in width, 32 feet in 
depth, running at the rate of six miles an hour, equal to 22,440,000 
cubic feet, weighing 701,250 tons; here the whole is confined to 
a breadth not exceeding 225 feet, and then it suddenly becomes 
sluggish at the whirlpool, (fig. 2, 4, entrance into the whirlpool). 
The solution is found in the structure of the rocks. The sy 4 
hard bed of quartzoze sandstone on which the debris at the rapids 
tests, is here broken thtough, under which lies a very soft red 
shale,* which has been scooped out by the resistless torrent from 
each side underneath this rock to an unknown width and depth. 
A passage is thus made for the flood to escape. The red shale 
crops out at Lewiston. 20% 
‘he annexed outline of Father Hennepin’s drawing is care- 
fully reduced from the lithographic print found in Lyell’s Travels 
im North America in the years 1841 and 1842. From the origi- 
nal Utrecht edition, 1697. 
: Be the prese 
Hall and ey img she commencement of the Canada Fall ~ 
43 
18, according to the euide-books, yards, to which, if we add 
only. one-third of the Canada Fail we shall have in all 680 yande 
* This is not the shale under the limestone as seen at the Falla 
