Carboniferous System. 49 



These fossils belong to the genera Solarium or Euomphalus, 

 Fleurotomaria^ Natica, Pecten., Trigonia, I'erebratula, Spirifer^ 

 OrthiSi Leptaena, Productus^ Turhinolia^ Ceriopora^ and Reto- 

 pora. Of twenty-six species collected by M. d'Orbigny, twelve, 

 or nearly the half, have the greatest analogy with the fossils 

 of the carboniferous series of Europe, and of these, three, viz., 

 Spirifer Pentlandi, Spirifer Boisst/i, and Producius Viliiersi, 

 are quite identical with the same species from Belgium and 

 Russia. We have the same genera ; also species having a 

 commou/acies, and three of them quite identical. The whole 

 fades of the fossils is so analogous, that at first sight we might 

 imagine that we were looking at the usual species met with 

 in the carboniferous rocks of Europe. 



Among the fossils which do not belong to the carboniferous 

 series of Europe we must remark a Trigonia {Trigonia antU 

 qua), a genus which has not hitherto been noticed below the 

 Jurassic formations. This curious discovery shews that M, 

 d'Orbigny has understood how to ascertain, not only the re- 

 semblances of the American formations to ours, but also the 

 differences between them, — differences which might well be 

 expected at a distance 6000 miles, and which it is only sur- 

 prising have not been found to be more considerable. 



After the Silurian and Devonian periods, the American 

 seas thus supported a different fauna from that of the two first 

 epochs, and one completely analogous in character to that 

 which lived during the carboniferous period in the seas of 

 Europe. This analogy does not now exist between the faunas 

 of the seas of Europe and of South America; and, as M, 

 d'Orbigny remarks, it indicates, in the ancient geological pe- 

 riods, an uniformity of climate no longer observable. These 

 inferences have so much the more weight, from being in this 

 case supported on a triple basis. We have already spoken of 

 the fossils which have induced M. d'Orbigny to refer the sys- 

 tem of clay-slates of the Bolivian mountains to the Silurian 

 system of Mr Murchison, and the system of quartzose sand- 

 stones to the Devonian system. Here, then, we have in South 

 America, three members of the great paljeozoic system, suc- 

 ceeding one another in the same order as the members of tho 

 same system in Europe, with which they have respectively the 



VOL. XXXVI. NO. LXXI. JAN. 1844. D 



