18 F. Leverett— Correlation of New York 
ing the borders of the western or Erie portion of the basin, we 
should expect beach lines and wave action generally at any 
horizon above the present level of Lake Erie to be less con- 
spicuous in the former than in the latter district. The fact 
that the raised beaches of the Lake Erie basin occur at only a 
few levels apparently indicates that the lake dropped rapidly 
from the level of one beach to that of the next lower, for had 
the interval of lowering been prolonged beachlets of consider- 
able strength would have been formed at various levels.* 
In the district east from the Lockport moraine we should 
expect wave action to be pronounced in but a narrow zone, 
even if the ice-sheet had withdrawn before the Crittenden 
beach was formed. If it did not withdraw until after that 
beach was formed we should expect, at most, but an ill defined 
zone of wave action. Upon examining the district eastward 
from northwestern Genesee county (where the Lockport 
moraine and the Crittenden beach intersect) we found a narrow 
belt at about the level of the Crittenden beach where the drift 
* In studying the effects of the waves the depth to which effective wave action 
extends becomes a question of considerable importance. The depth of lowest 
wave action is, of course, related to the magnitude of the waves and this to the 
size of the water body, being greater on the ocean than on our great lakes. The 
great lakes are, or were, each of the same general order of magnitude, and their 
wave work may properly be compared. Prof. Shaler and Mr. Gilbert have exam- 
ined jointly a district at the eastern end of Lake Ontario with this subject in 
mind. Prof. Shaler has published the following statement of results: ; 
‘* Heposed off shore Deposits—It might be supposed that wherever in relatively 
recent times a beach now elevated has been formed the surface of the earth below 
its level would retain some indications that it had been beneath the water. It 
might reasonably be expected that a submergence which had endured long enough 
to permit the formation of characteristic beach accumulation would have sufficed 
for the formation of a tolerably enduring marine deposit lying off shore.” 
‘“‘ At the outset of my studies of the elevated beaches of the Atlantic coast, the 
remains of which are of a rather fragmentary nature, I was led to doubt the 
verity of the indications by the absence of these marine deposits from the surface 
‘ of the lower lying land. To test the matter I resorted to the country lying on 
the east and south of Lake Ontario, where the well preserved Iroquois beach 
indubitably proves long continued sojourn of the waters at a considerable height 
above their present level. I found that below the plain of the beach the general 
surface of the country showed no distinct indications that it had been submerged. 
In fact I was unable to find any criteria which would enable me to discriminate 
the areas below and above the ancient sea-margin. It must be believed that 
where the submergence has endured for a long time a certain amount of sedi- 
ments would be laid down in the off shore district and that the period required 
for the formation of such a beach as that last mentioned should have brought 
about a considerable accumulation of clay. It seems, however, likely that in a 
few thousand years of exposure such clay deposits would, by the down bearing 
action of the rain waters, be carried down into the earth or washed away into 
the streams.” (Bull. G. S. A., vol. vi, pp. 151-152.) 
Mr. Gilbert’s testimony is as follows: ‘‘It seems to us that after going 50 feet 
below the lowest member of the Iroquois series there was practically no modifi- 
cation of the drift forms; and while riding over the drift hills the only indication 
we could see of the lake occupancy was a loamy deposit from a few inches to a 
few feet in thickness which could often be distinguished between the soil proper 
and the unmodified drift. The evident inference was that the water had fallen 
from one level to the other in a very short time.” (Personal correspondence.) 
