of North America with those of Europe. 47 



In Europe this stage is probably represented by the yellow 



sandstones of Ireland, and by slates and sandstones which we 



have seen in Westphalia, north of Hagen, and which have been 



described by Messrs. Sedgwick and Murchison. (Geol. Trans., 

 vol. v.) 



Above the psammites, or the siliceous strata, comes the carbon- 

 iferous limestone, which is exactly the equivalent of that of Eu- 

 rope, and which contains its most characteristic fossils. 



The third stage of the Carboniferous system is formed by 

 the sandstones and coal shales which surmount the preceding 

 limestone. Aside from their extent and their unexampled thick- 

 ness, they appear to be the representative of the coal deposits of 

 Europe. They contain, in fact, nearly the same plants, but they 

 are distinguished, nevertheless, by their marine origin, or at least 

 by their alternation with limestones filled with marine fossils. 

 These limestones, whose thickness is insignificant compared with 

 that of the whole of the coal series, are of great importance in the 

 theory of the formation of coal. Their fossils are nearly the same 

 as those of the carboniferous limestone.* The coal schists them- 

 selves contain very few fossil shells. Nevertheless, near Bloss- 

 burgh, in Pennsylvania, and in Maryland, are found certain spe- 

 cies analogous to those of the environs of Glasgow, in Scotland, 

 Wen as Euomphalus carbonarius , Bellerophon Urii, Machro- 

 cheilns curvilineus, Allorisma sulcata, and some very rare bi- 

 valves resembling the Uniones. 



Let us now pass in review the list of species common to the 

 two continents, and rapidly indicate the parallel modifications 

 which they present. According to our own observation, this list 

 ] s composed as follows. Phillipsia serninifera, Orthoceratites ca- 

 famus, Goniatites rotatorius* Nautilus tuberculatus, Bellerophon 



, "» J~T? I<m ,n uieir application, ana me lacts in mis case prove conclusively, 

 d fi l !f '*" e °^ 8e P arat * on between Carboniferous and Devonian is not yet so well 

 ned as tn at between Devonian and Silurian, or even between the lower and 

 u Pper divisions of the latter system.— J. H.1 



"°yisn, and some otners known in these thin beds of limestone in Ohio, ever 

 •**n seen in the great carboniferous limestone below ? For ourselves we are obli- 

 ged to confess, that we have never had the good fortune to see tnem in the latter 

 Potion i n a || t j le i oca ]j tie9 we nave visited. We cannot, moreover, for other rea- 

 ■£*»» feel willing to admit that the same fauna which flourished during the deposition 

 l " e great carboniferous limestone, reappeared at intervals after the commence- 

 ment of the deposition of the coal shales and sandstones, with plants indicating the 

 existence of dry land and fresh water. All the species we have collected from 

 ese intercalated beds of limestone in the coal measures of Ohio, though of ma- 

 ne origin, are specifically distinct from any we have seen from the limestone 

 below— J. hi * t 







