246 Address before the Association of American Geologists. 



Thus far, as we have ascended on the scale of rocks, we have 

 found, if I mistake not, so full a developement of the European 

 formations on this side of the Atlantic, that it would not be 

 strange, if at no distant period, this country should become clas- 

 sic ground for their study. But we now reach a wide hiatus of 

 the extensive groups of the lias, oolite and wealden, which have as 

 yet been scarcely identified on this continent. Humboldt did, 

 indeed, express the opinion, that he had met with the oolite in 

 the equinoctial zone of South America ; and Mr. Lea has descri- 

 bed some fossils from New Grenada, in the seventh volume, sec- 

 ond series, of the Transactions of the American Philosophical Soci- 

 ety, which he refers to the same formation. But Von Buch, in 

 his recent splendid work on some of the fossils of South America, 

 regards them as belonging to the cretaceous group. Mr. Conrad, 

 however, has just announced the existence " of well characterized 

 and undoubted oolite in the state of Ohio." — Report on the New 

 York Survey for 1841, 



When we rise still higher on the geological scale, we meet with 

 a remarkable group of rocks, occupying a wide belt from New Jer- 

 sey to Alabama, and much surface also in Mississippi, Louisiana, 

 Tennessee, Arkansas, and, as I am informed by Mr. Nicollet, ex- 

 tending from Council Bluffs on the Missouri, several hundred 

 miles westward, nearly to the Rocky Mountains, all of which 

 was identified, I believe, first by Prof. Vanuxem, with the creta- 

 ceous formation of Europe, although it contains no chalk. The 

 subsequent extensive and accurate researches of Dr. Morton, Mr. 

 Conrad, and others, have completely confirmed this opinion ; — and 

 it furnishes an interesting example of the value of organic re- 

 mains in identifying groups of rocks very much unlike in litho- 

 logical characters. It is another instance, moreover, of the enor- 

 mous scale on which geological operations have taken place in 

 this country. From the recent memoir of the veteran geologist. 

 Von Buch, just referred to, it appears that this same formation 

 extends through a considerable portion of South America, and 

 decidedly predominates among the secondary rocks of the Andes. 



Equally successful, as in the case of the cretaceous rocks, have 

 been the labors of Conrad, Vanuxem, Morton, Lea, the brothers 

 Rogers and others, in developing the tertiary deposits of this 

 country. The most northerly point along our coast where these 

 are found, is the island of Martha's Vineyard, or perhaps Nantuck- 



