390 
GEOLOGY OF- THE FOURTH DISTRICT. 
been gained in less than half the distance. Similar examples may be found in Seneca and 
Cayuga lakes; the outlet of the former, instead of pursuing its course through an ancient 
valley to Lake Ontario, turns to the eastward, and excavates a channel through the limestone 
and gypsum beds between that lake and Cayuga. 
Numerous similar examples might be cited, were it necessary, in order to account for the 
fact that the Niagara did not take the course by the ancient ravine to St. Davids. In any 
case it only requires that the superficial deposit should be higher than the rocky strata, and 
that the water once be directed in that course, and it will wear itself a channel sooner than 
remove the other deposit. 
In consideration of the argument that the channel of the Niagara has been worn by the 
action of the sea, it may be necessary to offer some analogous examples. In all ravines, or 
indentations, excavated in the face of sea cliffs, whether aided by a stream flowing in or not, 
we find a broad or trumpet-mouthed opening toward the sea, and they recede abruptly to a 
termination. They never present a long, narrow ravine of equal width ; and where of a 
length at all approaching that of Niagara, they have an opening many times broader than this 
at Lewiston. Numerous examples of ravines formed in this manner might be mentioned, but 
none of these resemble Niagara. In such instances they are broad enough to allow the 
stream to flow in the bottom, leaving waterworn materials along the sides, monuments of the 
abrading action of the waves. In the Niagara chasm there are no boulders, pebbles or gravel. 
The river occupies the whole width at the bottom, except a talus on either side, formed by 
angular fragments fallen from above. 
The valley of the Genesee, from Rochester to Dansville, offers a good example of a chan¬ 
nel excavated by the action of the sea during the emergence of land ; but this valley is broad, 
and partially filled with drift; the sides sloping gradually, and, for the most part, deeply 
covered with transported materials. 
The small amount of wearing, or the recession of a fall, accomplished by a stream during 
the period of our observation, might incline us to doubt the possibility of any body of water 
having excavated its channel backwards for a length of seven miles, and to a depth of from 
three to five hundred feet. But if the period of one life be sufficient to admit of observation 
proving the smallest amount of recession, then it is only requisite that we should carry on the 
process for an indefinite period, to accomplish the utmost that we require ; or that we extend 
backward our imagination regarding time, in order to demonstrate what is already accom¬ 
plished. Now it is proved that within the recorded observations of persons residing in the 
vicinity of Niagara, that the falls have receded within their recollection. Therefore, if we 
are able to prove that this ravine could not have been excavated by the sea, during the 
emergence of the land, we have only this mode of operation left to account for its formation. 
It is barely possible that there may have been a fissure in the present course of this river, 
which gave the first direction to the stream ; but I have not been able to find any farther 
evidence than what has already been given on this subject. I have remarked that the surface 
of the limestone declines to the eastward, and I have been informed by Mr. Roy that it also 
