¥ Address before the Association of American Geologists. 247 
et. Thence in passing southerly, we find them occupying Long 
Island and the eastern part of the Atlantic states, from New Jersey 
to Florida, and the southern part of the Mississippi valley. These 
too correspond to the other features of our geology, in being of vast 
extent and of decided characters. ‘Three principal groups of these 
strata, as described by Conrad and Morton, viz. the lower or 
eocene, the medial, and the upper or newer pliocene, seem to be 
well made out om this side of the Atlantic. The group named 
post-tertiary by Mr. Lyell, is found also in the northern part of 
w York and in Canada, containing shells of a more arctic 
character than those now living in the same latitudes, 
Excepting the remarkable insulated labors of Mr. Hayden, the 
drift, or diluvium of this country, has, until recently, received less 
attention than almost any other formation. The same has been 
true in Kurope. This results i in-part-from the fact, that it cannot 
be successfully studied: until the character and limits of all the 
stents formations: are: well mileicotonods: Phe Hate surveys, 
however, 
to show us, that-though a difficult subject, it is one of the most 
interesting in the whole history of our rocks. 
-It is an important inquiry, whether. Ueilaliasinnene: ay drift 
in this country, correspond with those of the eastern continent. 
Until recently, I confess, I have doubted. whether some of th 
most striking of these phenomena were not much more. fully 
here than in most countries of Europe. . I refer par- 
ticularly to the smoothing, polishing, scratching and furrowing 
of the rocks in-place, and to those accumulations of gravel, 
bowlders, and sand, which form conical.and oblong tumuli, with 
tortuous ridges of the same, and which abound in the northern 
part of the country; from Nowa: Rania fa the Rocky Mountains. 
Battherecent ecurate descriptions by Agassiz, 
Buckland, Lyell, Sefstroom, and others, have satisfied me of the 
almost:exact identity of the facts in relation to drift on the two 
continents. . ‘The resemblance, however, seems to be most com- _ 
plete in» this» respect between Scandinavia and this. country. 
Except in. Sweden, I have not yet seen evidence that the scarifi- 
cation of the rocks is as: common in Europe asin New England, 
where if they were denuded of soil it seems to me, one third of 
the surface would be found: smoothed and furrowed. But it is 
now found to be very common in Scotland, England, and espe- 
