68 GEOLOGICAL MEMOIRS. 



argument for referring these beds of Ferrones and Pelapaya to the 

 Devonian period. 



On the whole, therefore, we find that of thirty-one species ob- 

 tained from these localities, three, namely Terebratula DaleidensiSy 

 Orthis orbicularis^ and Leptcena Murchisoni^ are true Silurian, four 

 are Silurian and Devonian, one ( Orthis resupinata) is Devonian and 

 Carboniferous, eight are exclusively Devonian, and fifteen are new. 

 Of these latter, however, three have been found in the Devonian 

 rocks of other countries, so that as many as eleveit, or about one- 

 third of the whole number of species known, are exclusively Devo- 

 nian. 



Besides the fossils of Ferrones, Pelapaya and the neighbourhood, 

 M. Paillette has also sent some specimens from Arnaos, where the 

 beds of true coal, which he has described in his memoir, appear to 

 be covered up by limestones similar to those of Ferrones. Among 

 the species thus obtained, the specimens of which are generally less 

 perfectly preserved than those previously described;, we have Tere- 

 bratula reticularis {prisca), T, Ezquerra, T.primipilaris (Von Buch), 

 Orthis resupinata, O. striatula, O. arachnoidea, and the Spirifer 

 Pellico, so characteristic of the Ferrones limestones. It is impossible 

 to doubt that these beds of Arnaos are of the same age as the 

 others*. 



As to the fossils of Cabrales, for which we are also indebted to 

 M. Paillette, they are quite distinct from the preceding, and cer- 

 tainly announce the presence of the true carboniferous series at this 

 point. They consist oi Productus semireticulatus. Mart. (antiquatuS) 

 Sow.), and P. te?iuistriafus, De Vern., Spirifer attenuatus or striatum, 

 and S, Mosquensis. 



D. T. A. 



* We think it right to call attention to this fact, since it is the first time that 

 fossils unquestional)ly Devonian have been found regularly superposed on beds of 

 workable coal. All the great coal and anthracite deposits of England, America 

 and Russia are well known to be superior in geological position to the Devonian 

 system. 



