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 on this side of the Atlantic. The group named 

 post-tertiary by Mr. Lyell, is found also in the northern part of 

 New 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 Europe. This results in part from the fact, that it cannot 

 be successfully studied until the character and limits of all the 

 subjacent formations are well understood. The state surveys, 

 however, have brought to light enough of our diluvial phenomena 

 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 the phenomena of drift 

 in this country, correspond with those of the eastern continent. 

 Until recently, I confess, I have doubted whether some of the 

 most striking of these phenomena were not much more fully 

 developed 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 Nova Scotia to the Rocky Mountains. 

 But the recent investigations and accurate descriptions byAgassiz, 

 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 as in 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- 



