126 The Falls of Niagara, 
taken in connection with the appearance of the chasm from 
whence the waters issue. The height of the chasm (fg. 23. 
cc) in the solid rock, independent of the receding diluvial 
soil, is about 200 feet to the plain ; its width at the opening (d d) 
is, perhaps, 400 yards. On viewing this highly interesting 
scene, the mind is irresistibly carried back to the time when 
a mighty flocd poured over the once-united precipice at d. 
This fact, I think, cannot be doubted by any one who sees its 
present appearance, and who duly reflects on what a falling 
body of water, so immense, so rapid, and so resistless in its 
course as the river of Niagara, is capable of accomplishing in 
a series of ages. Taking it for granted that the Falls have 
once been at c, it is a curious question to enquire, When were 
they there? An approximate solution to this enquiry will be 
given, if Mr. Forsyth’s statement be allowed of the Falls having 
receded nearly 50 yards in the last 40 years, and ifit be granted 
that this has been the constant ratio of their recession. The 
distance from the opening (c) to the Falls is 7 miles, equal 
to 12,520 yards, which gives 9856 years for the period in 
which they have been retrograding to where they now are. It 
appears evident, from circumstances to be hereafter stated, 
that the waters were formerly more abundant than they are at 
present; nor can we be certain that the rocks were equally 
hard in every part of their extent, in which case, the process 
of disintegration would be much quicker, and the period of 
recession shorter. 
The drawing (fig. 23.) is intended to represent a birdseye 
view or map of the country, from an imaginary point above 
the chasm at Queenstown, and to comprise a view of the 
river as far as Lake Erie (17). The distance, as I have before 
mentioned, from Lake Erie to the Falls is 25 miles, and 
from the Falls to the opening (c) 7 miles. The waving 
lines (ff) mark the alluvial or diluvial sand cliffs above the 
limestone precipices (d). This diluvium covers a great part 
of the table land. The lines gg mark the separation between 
the limestone and the lower shale (24). It may be proper to 
observe, that these lines are more distinctly represented than 
what are seen in nature, the rocks (2) having banks thickly 
wooded up their sides, and the edges of the precipice are here 
and there broken. 
It is evident, from the curved and water-worn appearance 
of the diluvial banks (f/f), in which large boulders are em- 
bedded, that the waters must once have flowed nearly on a 
level with these banks. This important consideration again 
carries us back to the period of time when the chasm (c) did 
not exist, when the parts dd and /h formed but one and the 
