North America. 551 
near Queenstown. The first or uppermost fall, he argues, must 
have been of moderate height, when the land was sufficiently raised 
to wear away the Niagara shale, and undermine the incumbent lime- 
stone, which is of slight thickness at its termination near Queens- 
town. This upper fall having thus cut its way backwards, while 
the remainder of the escarpment was still protected from denudation 
by submergence, the second fall would next display itself on a further 
upheaval of the land, the river being thrown over a lower ledge of 
hard limestone ; finally the land continuing to rise, a third cataract 
would be caused over the hard quartzose sandstone, which rests on 
the soft red marl at Lewistown. These several falls would, at first, 
each recede farther back than the one immediately below it, their 
distance being greater or less in proportion to the slow or rapid 
rate at which the land emerged, but they would all at length be 
united into one fall, the uppermost limestone becoming thicker in 
its prolongation up the river, and thus retarding the retrogression 
of the highest cataract, while the two lower falls would continue to 
recede at an undiminished pace, until each had in its turn over- 
taken the uppermost. 
In describing the coast sections of Massachussets, and in trans- 
ferring our attention to the interior of Kentucky—localities already 
rendered classic by American geologists and paleontologists— 
Mr. Lyell has placed before us a clear view of other leading points 
of the changes which that great continent has undergone. 
The tertiary deposit at Martha’s Vineyard, on the coast of Massa- 
chussets, had, indeed, been described by Professor Hitchcock, who 
seeing the highly-inclined position of the beds, the great variety of 
structure as well as colour of the strata, and the obscure casts of 
shells which they contain, was much impressed with their apparent 
similarity to the Lower Tertiary beds, or Plastic and London clay 
of the Isle of Wight described by Mr. Webster. By a careful ex- 
amination however of these strata, and by collecting a larger and 
more varied suite of organic remains than was known to Professor 
Hitchcock, Mr. Lyell has come to the conclusion, that so far from 
being of the Eocene age, this formation is at most of no higher 
antiquity than the Miocene. This result has been obtained by 
finding the teeth of several specimens of fishes which belong to species 
obtained by Mr. Lyell in the Miocene “ Faluns” of Touraine, and 
determined by Agassiz; together with vertebra, referred by Mr. 
Owen to two species of whale, the teeth of a seal, and the skull of 
a walrus; an association which cannot fail to convince geologists 
that the materials of this island, off the coast of New England, were 
accumulated at no very distant geological epoch. The high inclina- 
tion of these party-ccloured sands, clay and conglomerates, and the 
curvatures which some of them have undergone, probably through 
great lateral pressure, are clear proofs that they have been power- 
fully upheaved and dislocated ; whilst the gravel and boulder forma- 
tion which covers their edges horizontally, compels us to conclude, 
that the disturbed beds were submerged during the boulder period, 
and subsequently elevated to the position in which we now see them, 
