1848.] MURCHISON ON THE STRUCTURE OF THE ALPS. 301 



even in the Pyrenees, I am disposed to consider this a local phaeno- 

 menon, similar to that described by M. Favre in a portion of the 

 Savoy Alps. It is needless, however, here to speak of lines of dislo- 

 cation or transgressive deposits which I have disposed of elsewhere, 

 as we are now merely dwelling on palseontological data and regular 

 order of superposition ; and the result of the researches of M. Tala- 

 vignes is, that, with the exception of one Gryphsea, all the fossils of 

 his two systems of nummulitic rocks are of tertiary forms. 



An argument used by M. Dufrenoy to sustain the opinion of M. 

 de Beaumont and himself, that the nummulite rocks formed the up- 

 permost stage of the great cretaceous system of the south, has, it 

 seems to me, fallen to the ground*. That author had indicated that 

 the highly inclined nummulite strata of St. Justin in the Landes were 

 surmounted by horizontal beds of calcaire grossier. On a scrutiny 

 of this point, however, MM. Raulin and Delbos have proved, that the 

 supposed calcaire grossier is a true Bordeaux miocene, and therefore 

 we have there simply such a hiatus in the tertiary series as occurs in 

 many parts of the Alps and Italy. M. Raulin has, indeed, gone 

 further, and has proved, through the species of echinodcrmsf, that in 

 the same region (Dax) there is a true equivalent of the white chalk, 

 and that the overlying nummulitic rocks are loaded with eocene 

 species. He insists, that whenever the nummulite group occurs, 

 there is no other representative of the eocene. Hence M. Raulin 

 believes that the great upheaval of the Pyrenees took place after the 

 eocene epoch ; and this is just what has occurred in the Alps. M. 

 Rouant has, indeed, described a " terrain eocene " in the environs of 

 Pan, which is the very same as the nummulitic group elsewhere, and 

 being in an intermediate position, it is most satisfactory to know that 

 it contains thirty-four fossil species of the Paris basin and five of the 

 Vicentine. 



Now, whatever these deposits in the south of France may be called, 

 they are unquestionably of synchronous date with the nummulitic 

 group of the Alps ; for nearly every one of the same species of num- 

 mulites and orbitolites, besides many echinoderms and shells, occur in 

 both regions in strata occupying the same place in the geological scale J. 



* Bull. Soc. Geol. Fr. vol. iv. p. 561. f Ibid. vol. v. p. 114. 



i Seep. 195, and the note on M.d'Archiac's identification of the species I brought 

 from the Alps with those of the south of France. That able author has written to 

 me, that he sees no zoological reason why that which he has termed the Asiatico- 

 Mediterranean nummulitic group, extending, as he says, from the Asturias to the 

 banks of the Brahmapootra, may not be the true type of the lower tertiary forma- 

 tion, whilst that which we have hitherto regarded as such (Paris, London, &c.) 

 may have been due to local causes, and circumscribed to some ancient gulf of north- 

 western Europe. "What he still requires, before he modifies the opinions he has 

 already expressed, are, clear proofs of geological and stratigraphical relations, and 

 he hopes to find this point sustained in my memoir. Whilst speaking of the zoo- 

 logical characters of the nummulitic group, I am also happy to say, that a number 

 of its fossils, forming part of a large collection in the Woodwardian Museum of 

 Cambridge, procured from Count Miinster, and ticketed by that naturalist from 

 various Alpine localities cited in this memoir, have all been classed as eocene ter- 

 tiary by Mr. F. M<=Coy (the assistant of Professor Sedgwick) after a careful com- 

 parison of them with types of that age from other tracts. 



VOL. V. PART I. Y 



