ing above the soil, afford conclusive proof, tha 
: es 
Geology and Topography of Western New York. 101 
- Wherever the strata come in sight on the island, they conform 
to those in the bed of the rapids, and are equally water-worn and 
denuded. A portion of rock, recently uncovered by the en- 
croachment of the rapids upon the west bank of the island, pre- 
sents the same features, and can only be distinguished from those 
which have buffeted the fury of the torrent from time immemo- 
rial, simply by the knowledge of the naked fact of their recent 
exposure. One of the principal ledges, also, which extends en-— 
tirely across from the Canada shore, may be. encod some distance 
of the bed of the rapids, and the surface 
derlies the tertiary on the island, was effecte the same agent 
and at the same time. ren 
No rapids could then have existed at this sists, for the island 
has since received a tertiary deposit of clay, horizontally strati- 
fied, which is overlaid by one of gravel containing fresh water 
shells. These two deposits, at the lower end of the island, be- 
tween the cataracts, measure thirty three feet in thickness. I 
have already mentioned, that this clay resembles the numerous 
beds in this vicinity ; they all probably belong to the same gene- 
ral deposit. Mr. Rogers thinks this deposit took place from the 
waters of a tranquil lake.* The fact, however, of its contain-. 
ing gravel stones and water-worn fragments of the rock on which 
it rests, (as do all of these beds,) would seem to indicate a dif- 
ferent origin. -I suspect this clayey deposit may have been 
brought on by the overflowing of tides, after the rocky bed had 
become so much elevated as to be protected from the violence of 
the surge. The surface, where large tracts are overlaid by it, is 
marked by meandering-‘swales, which strike the observer as fit 
channels 
s to conduct the water back to its proper level at ebb | 
tide, after having parted with a portion of its sedimentary matter. 
No proof surely could be more conclusive than these tertiary beds 
on Goat Island, that the rapids have not — Biases — 
_ patt 2s, 
be the fact in coped to the cataract itself. 
From ‘the Falls to the Whirlpool, a distance of about © 
miles, I have observed no indications which have a direct bear- 
ing on the. question of recession; but»at this latter place, phe-. “3 
at ; 
oe ie’ 
= American Journal, Vol. XXVII, p. 330. 
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