RANGE OF THE PALAEOZOIC ROCKS THROUGHOUT AMERICA. 5* 
loaded with Pentamerus oblongus, the very fossil hy which we have distinguished 
the same zone in the British Isles ’, Norway and Sweden ! 
Ihe great abundance of corals constitutes in the United States, as in the old 
continent, the striking feature of the Upper Silurian rocks, and, as with us, the 
C'Citenipora escharoides, Favosites Gothlandica and F. alveolaris there form massive 
reefs. These coralline rocks may, without hesitation, be grouped with the Wenlock 
limestone ; for it is in this stage also that the Calymene macrophthalma, C. Blumen- 
bachii, Bumastus Barriensis, Asaplius caudatus, Homalonotus delphinocephalus also 
occur, with several mollusca, which remind us of the European fauna of this 
formation 2 . 
The Silurian system, thus clearly divisible into two groups, is overlaid in the 
United States by shales, sandstones and flagstones 3 , which must be referred to the 
Devonian system, for they contain, in effect, the very fossils which we have pub- 
lished as characteristic of that age from the Boulonnais in France and the Rhenish 
provinces, among which are the Spirifer V erneuilli and Orthis crenistria or umbra- 
culum. The beds are crowned by a red sandstone with peculiar fishes, which 
every one must at once admit to be characteristic of the Old Red Sandstone of 
the British Isles. If, however, from this fact some persons might suppose, that a 
division were practicable between the Old Red Sandstone and the Devonian shelly 
limestone, we beg to refer, not only to our memoir upon the Rhenish provinces 
before cited, but also to the third and fourth chapters of this work, wherein 
pi oofs will be adduced of the absolute intermixture of these ichthyolites and 
shells in the very same strata. Lastly, the Carboniferous system is distinguished 
m North America as elsewhere by its Producti, whilst the coal-beds contain plants 
lor the most part identical in species with those of Europe, and by shells, such as 
the Bellerophon TJrii and Euomphalus carbonarius (Sow.) , which are undistinguishable 
Irom species of the Scottish coal-fields 4 . 
This is the Horderly and Woolliope limestone of the Silurian rocks (see Sil. Syst. p. 217, 414, 419). 
M e shall show in the sequel the exact position of this limestone in Norway and Sweden, where it contains 
the same species of Pentamerus, which in Russia is represented by our P. borealis. 
2 We may here further mention some of the true Upper Silurian molluscous species that we have 
recognised in the collection of Mr. Lyell. Cytherina alta (very near to C. Balticd), Terebratulu Wilsoni, 
try p a spheerica, Pentamerus {A try pa) galeatus, Lepteena depressa, L. euglypha, Orthis canalis. From the 
work of Mr. J. Hall we may further cite the Wenlock species Spirifer cardiospermiformis and Hypan- 
thocrinites decorus (see Silurian System, p. 630, 672). 
Ihe Tully, Genessee, Portage and Chemung groups of Mr. J. Hall. 
M- de Vemeuil recognised these good British types in a collection brought by Mr. Lyell from certain 
ec s of shale at Frostburg in Maryland which rest directly on a bed of coal. 
B* 2 
