354 
GEOLOGY OF THE FOURTH DISTRICT. 
facts, he maintains the existence of an inland sea, covering all that portion of country below 
1000 feet above tide water, and that it has been successively drained to points corresponding 
with the following elevations, which I have taken from a plan constructed by him.* At 
some of these points the water remained long stationary, while in others only for a very short 
time, the duration probably depending on the facility with which the barrier at the outlet was 
reduced. 
Above the level of Lake Chitario. Above the level of the sea. 
o_ 
FEET. 
_ 762 .. 
FEET. 
__ 996 
L_ _ 
_ 680 .. 
__914 
G__ 
. 420 _ 
_ 654 
E __ ... _ 
_ 344 
_ 518 
D__ 
.. _. 308 _ 
_ .. _ 542 
C ... 
_ 280 _ 
_ .._ .. _ 514 
B_ _ 
_ 208 .. ._ ... 
_ 442 
A ._ _ .._ _ 
_ 108 . 
___ 352 
el of Lake Ontario,_ 
__234f 
This theory, when connected with so many authentic observations, impressed me very 
favorably; but subsequent observations have not been sufficient to convince me of its truth; 
yet my examinations not having been especially directed to the subject, I may have over¬ 
looked important facts. The fact, however, which is demonstrable, that the great valleys 
of the Champlain, and St. Lawrence and Hudson, were excavated previous to a submergence 
of the land, and the formation of extensive tertiary deposits, likewise proves that the ocean, 
at this period, would occupy a large portion of the valley of Lake Ontario, and even, perhaps, 
of higher lake valleys. These are circumstances to be taken into the account in estimating 
the probability of the existence of such a sea. 
Modern Lake Ridges and Beaches. 
Connected with ihis subject is that of the modern beaches and ridges along Lake Ontario. 
These are such as may be formed in the space a few weeks or months, or even during a 
single storm. Some have stood for ages, and others are the sport of the changing winds and 
the fluctuating level of the lake. 
Those which I have examined more particularly, are in Monroe county, and a few of these 
will serve to illustrate the character of the whole. The following map, including a small 
portion of Monroe county west of the Genesee river, will render these remarks better under¬ 
stood : 
* The views of Mr Roy, have, I believe, been made public in some communications to the Geological Society of London ; but 
I have not seen the publication, and my information is derived from his communications to myself. 
t The elevation here given is three feet higher than that usually given by engineers in the United States. 
