References to North American Localities. 149 



ty, and in a region where tents and extemporaneous log cabins 

 were the only lodgings, it will require no great effort to conceive 

 the amount of labor which has been bestowed on the subject of 

 this report. The only previous survey of the Bradford district, 

 was. we believe, a partial one, made a few years since by R. C. 

 Taylor, Esq., but we are not aware that even of this any account 

 has been published. The State geological survey of Pennsylva- 

 nia has not yet reached Bradford county, but we cannot doubt 

 that when it arrives in this region, the investigations of Prof. 

 Rogers will fully confirm those of Prof. Johnson. 



Art. XIX. — References to North Aonerican localities, to be appli- 

 ed in illustration of the equivalency of Geological Deposits on 

 the eastern and western sides of the Atlantic ; by Amos Eaton. 

 Brongniarf s theoretical table of succession , is adopted. 



Bakewell, in his popular and very instructive treatise on geol- 

 ogy, manifests a preference for the views of Brongniart. Ameri- 

 can geologists who have attempted the application, find a remark- 

 able accordance of his system with our own rocks. 



I limit myself, in this article, to definite American localities, for 

 fixing the limits between the seven classes of M. A. Brongniart, 

 as applied to this country. 



For the purpose of making myself understood by those who 

 may not have seen the original, I insert a familiar view of the 

 outline of his system, as first published in 1829 ; which, as the 

 author has signified to me in the present year, he still adopts. 



I have been highly interested and mnch instructed, by the 

 striking application of the groups of De La Beche, to our rocks. 

 But the geological deposits of England, appeared to me, (from his 

 descriptions,) to be too limited in extent for giving laws in detail 

 to our vastly extended deposits.* 



Bivongniart's seven classes of rocks and earths (Roches 

 et Terrains). General groups of organic remains are chiefly 



* About seventeen years since, I was severely censured in a public journal, for 

 adopting De Luc's suggestion, that European geologists must cross the Atlantic, to 

 find stratH of sufficient extent for giving laws of generalization to their own rocks. 

 I believe I can congratulate our scientific friends almost with the assurance, that we 

 are to expect visiters of similar views, the present summer, of very high standing. 



