= 
Peer ere 
24 L,. Lesquereux on the Origin and Formation of Prairies. 
above, all the highlands of Indiana and Ohio should have been 
also deep under water. For, the highest point of the Ohio 
canal, at Licking, being 890 feet above the sea, there is still about 
500 feet of difference between this point and the level of the 
Iowa prairies. The whole high country in Ohio and Indiana 1s 
t. a 
indeed, can deny that the whole surface of the — 
extension 0 e Michigan, or of the basin of our lakes, a 
epoch of submergence which has left its traces over the whole 
extent of ntinent, is narrowing the phenomenon of a 
nearly horizontal plains, which 
vast sheets of water, lakes, and swamps. If the wider expanse 
of our lakes at former times is understood in that ways it is indeed 
undeniable. But, as we have already said, these lakes cannot be — 
considered in the phenomenon as causative or primitive agents. — 
And if it is so, all the deposits of that epoch belong to the same © 
lacustrine formation, and as all these surface deposits which were 
not horizontal are generally wooded, and often densely so, we — 
are already authorized to conclude that the so-called lacustrine — 
formation has, by its nature, no direct relation to the prairies. 
Before passing to another of the statements of the author, I 
would like to ask if there is not a contradiction in asserting that — 
there was “little difficulty in discovering the true origin of the 
so-called ‘wet prairies’ so common in Ohio and Michigan, and 
now usually termed ‘ marshes,’ ‘swales,’ ‘bogs,’ and in roving 
ere ee reson 
of the absence of ordinary upland trees from their surface,”* and 
to say, in considering my opinion identified by the author with 
the former, that “it is so well known that there is no situation _ 
so wet but certain trees will flourish in it,” (referring here to the — 
il of swamps.)’ Is it not also a contradiction to acknowledge 
that the wet prairies, along the shores of our lakes, are caused 
6 : Manual of Geolog 
sc ebateesenardhioeke Sete Tid. p. 554. 
* This Journal, [2], xxxviii, 333. * This Journal, ibid, p. $43. 
