ON OE ee i Ce ee rT 
192 : Cincinnati Society of Natural History. 
whole formation consists of the disintegrated rocks of the immediate 
locality, or those at no great distance north. The grooves and 
scratches upon the rocks between Niagara and Hamilton, have a 
north and south direction. 
In 1847, W. KE. Logan* found on the north shore of Lake Superior, 
about three miles below the Petits Ecrits, six terraces, in addition to 
the summit, which, presenting a level surface throughout the whole 
length, may be considered a seventh. Blocking up the extremity of a 
deep cone from the rock on one side to that on the other, the accumu- 
lation is a barrier to an extensive flat and marshy surface, that spreads 
out in a valley behind, down to the level of which there is a rapid slope 
from the summit of the drift, at a distance of about 1,000 yards from 
the margin of the lake. The height of the ancient beaches as measured 
by a pocket spirit-level is as follows: 
Above the Lake. Above the Sea. 
Feet. F 
ee eet. 
Beste. ES yo. hie Goel ave, oo. 4s ale ee 30 627 
Lol OG aaa eae MR eee tone nee SE LS ER AC 40 637 
EXCL 1 RE aaah eran iC AN oi epred Mec Airey cai ls 90 687 
Ppp 07 8 cl Ode oie eek RN Re 224 821 
Bila» © sated Seater ae J Sid i as 259 856 
I oh oe. re as iy aes eo, ne re 267 864 
fit > OT SUMMIG. noe eee Ce ee 331 928 
The 3d and 4th beaches are the most decidedly marked, the steps, 
rising behind them, sloping up at an angle of nearly 30°. 
Alexander Murrayt+ described the drift on the Kamanitiquia river, 
which flows into Lake Superior, near Fort William, as consisting be- 
tween McKay’s mountain and the Grand Falls, where the principal 
display was found, of a light buff-colored clay, covered over by strati- 
fied yellow ferruginous sand, both together attaining a thickness of 
60 feet above the level of the water. Banks of sand were found on 
Dog river, at a much higher level than the deposit further down. 
In 1848, John L. Leconte{ described, from a Post-pliocene deposit 
in acrevice in northern Illinois, Platygonus compressus and Anomo- 
don snydert. 
Mr. Charles Whittlesey§ designated the different beds of the drift 
in Ohio and the West as follows : 
* Geo. Sur. of Canada. 
+ Ibid. 
t Am. Jour. Sci. and Arts, 2d ser., vol. v. 
§ Lbid. 
