96 Geology and Topography of Western New York. 
— The northern boundary of the terrace, as before stated, termi- 
nates by an abrupt precipice, rendered more rugged and forbidding 
in appearance, by the disintegration of the shale on which it rests ; 
causing the harder strata to project from the bank, and when su 
‘* _, ficiently undermined, to be precipitated to the plain below. ’ This 
~ action goes on, till the talus covers the face of the shaly strata, 
and protects them from further disintegration. The mural preci- 
_ pice above might apparently remain for ages, without suffering 
material change. 'This escarpment is indented by: numerous Fra- 
vines which penetrate the bank to a greater or less distance. The 
streams which now occupy these indents, are mostly insignificant 
in size ; while many, some of which extend. farthest back from 
the oalarhvoat drain but a few hundred acres, and are only oc- 
cupied by the water which oozes from their banks, except during 
heavy rains, and the thawing of the snow at the end of winter. | 
When viewing this escarpment, it is difficult to resist the conclu- | 
sion, that the terrace once extended much farther north, and has i 
been undermined and broken down by the action of the surge. _ 
Not unfrequently,. persons who visit the falls of Niagara, and 
superficially examine the topography of the’ surrounding region, 
conclude, that the cataract was once located at Lewiston, _ seven 
miles below its present location. Full of this grand eonc eption, 
and without taking. into the account the causes which gave rise | 
to these general topographical features, they first attempt to ascer- 
tain its perpendicular height at that time. Having settled this to 
their satisfaction, they often launch forth into a train of caleula- 
tions, alike unprofitable and éxtravagant ; first to determine their 
age, and then, the number of years they will occupy, in their 
backward course, before they will invade the rocky ramparts of 
Lake Erie.* But, as in the onset, the origin of the cataract, one 
of the most important terms of the problem, is entirely omitted, 
their conclusions are wholly erroneous, and are entitled to as 
little consideration, as the ‘baseless fabrie of a dream.” | 
) 
. 
‘ * After all, parkas those So ieae t who Suis view the falls in theory, are the 
most prolific in drawing such conclusions. A series of lakés, situated like this 
DP hg, Aen ih TRS EE Cot Aten, BES a OR te ap ee LONE Pie Le, eae are 
the ear this hypothetical deluge, which is to Sa the fair valley 2 
oe Lawes 909 Gah hence, is cited to ustrate 
