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be entirely due to denudation; and he has no hesitation in attribu- 
ting this escarpment, as well as the Helderberg, to the action of the 
sea; these great inland cliffs having far too great a range to have re- 
sulted from a former extension and higher altitude of Lake Ontario. 
The next question, whether the ravine through which the Niagara 
flows is to be regarded as a prolongation of the Queenstown escarp- 
ment and referable to the same period, or has been cut through by 
the river, is, the author states, of greater difficulty. From his own 
observations, he concludes that the ravine has been formed by the 
river; but he assumes, that a shallow valley pre-existed along the 
line of the present defile, resembling the present one between Lake 
Ernie and the Falls. His reasons for conceiving that the river has 
been the excavating agent, are, lst, the ravine being only from 400 
to 600 yards wide at the top, and from 200 to 400 at the bottom, 
between Queenstown and the Whirlpool; 2ndly, the inclination of 
the bed of the river, 144 feet per mile, being everywhere cut down to 
the regular strata; 3rdly, the fact that the Falls are now slowly re- 
ceding; 4thly, that a freshwater formation, which the author ascribes 
to the body of water which flowed along the original shallow valley, 
exists on Goat Island and half a mile lower down the river, and 
could not have been deposited after the Falls had receded farther 
back than the Whirlpool. Mr. Lyell considers that the indentation 
of about two acres on the American side of the Niagara, and not re- 
ferable to the action of that river, is no objection to the theory of the 
recession of the Falls, because he conceives that the stream flowing 
down it could have effected the denudation, aided by atmospheric 
agents; and because a similar objection might be founded on a ra- 
vine on the Canada side opposite the Whirlpool, where several par- 
allel gullies have been deeply eaten into by streams. The charac- 
ters of this ravine were carefully examined by Mr. Lyell and Mr. 
Hall, and appear to have escaped previous observers. .What was 
anciently a ravine joins the defile of the Niagara at this point, but 
it is entirely filled with horizontal beds of drifted pebbles, sand and 
loam ; the first, near the bottom of the deposit, having been cemented 
into a conglomerate by carbonate of lime. This is the only interrup- 
tion of the regular strata along the course of the Niagara; and Mr. 
Lyell observes, it is desirable to ascertain if it be a prolongation of 
the ravine which intersects the great escarpment at St. David’s, west 
of Lewistown. 
The author states, that he is by no means desirous of attaching 
importance to the precise numerical calculations which have been 
made respecting the number of yards that the Falls have receded 
during the last half century, as there are no data on which accurate 
measurements could be made; and because fifty years ago the district 
was a wilderness. Mr. Ingrahaw of Boston has, however, called his 
attention to a work published by the French Missionary, Father Hen- _ 
nipen, in which a view is given of the Falls as they appeared in 1678. 
Goat Island is represented dividing the waters as at present; but 
besides the two existing cascades, a third is depicted on the Canada 
side, crossing the Horse-shoe Fall at right angles, and appears to 
