co)npare:l with that of Europe. 1 19 



Fusulina cylindrica, so characteristic of the carboniferous 

 limestone of Russia, occurs in the slates or siliceous beds of 

 the coal sandstones of Ohio. And as to plants, the immense 

 quantity of terrestrial species identical on the two sides of 

 the Atlantic, proves that the coal was formed in the neigh- 

 bourhood of lands already emerged, and placed in similar 

 physical conditions. 



With the carboniferous system terminates the palaeozoic 

 formation in North America. During all the time of its de- 

 position, the surface was free from great disturbances. Slow 

 and insensible oscillations had caused to emerge areas, more 

 or less circular, of the submarine surface, where the Silurian 

 and Devonian deposits were made, and had contracted the 

 limits of carboniferous deposits ; but the horizontality of the 

 beds was not disturbed. It is only after the carboniferous 

 that an energetic force, folding and raising the terrestrial 

 crust, gave birth to the chain of the Alleghanies. The manner 

 in which the plications, largely undulated at first, contract, 

 multiply, and fold over, in going from northwest to southeast, 

 towards the metamorphic and granitic rocks, situated most 

 frequently beyond the chain, properly so called, has been per- 

 fectly elucidated by the two Pi'ofessors Rogers.* 



It does not enter into our design further to extend this 

 notice ;t having fulfilled, according to our ability, the end 

 which we proposed, to establish a parallel between the pa- 

 laeozoic formations of North America and Europe. Permit 

 us, in conclusion, to present a resume of the course we have 

 followed, and the principal results at which we have ai'rived. 

 In order to make the interest and importance of this paral- 

 lelism fully understood, and the light which it throws upon 

 the knowledge of palaeozoic deposits in general, we have shewn 

 the advantageous geological conditions of North Ainerica, 

 and how, owing to the horizontality of the beds over great 



* On the Physical Structure of the Appalachian (.'hain, as exemplifying the 

 Laws which have regulated the Elevation of Great Mountain Chains generally. 

 By \S . B. and II. D. Kogers. 



t We have only extracted that part of M. dc \'crneuirs notice wbidi refers 

 to the f'arboiiiferouR Fauna. — Edit. Pliil. Journ. 



