322 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [April 8, 



of M. {Trilophodon) Borsoni and M. (Tetralophodon) Arvernensis, 

 which are PHocene. 



M. (Triloph.) Borsoni, Isaac Hays (PHocene). 



M. (Triloph.) tapiroides, Cuvier, 



M. (Triloph.) angustidens, Cuvier , pro parte. 



M. (Tetraloph.) longirostris, Kaup. 



M. (Tetraloph.) Arvernensis, Croizet ^ Jobert (Pliocene). 



The British fossil Mastodon, and its comparison with M. angus- 

 tidens, M. Arvernensis, and M. longirostris. — The remains of only 

 one species of Mastodon have hitherto been discovered in the British 

 Isles, in what is called the Older Pliocene " Red Crag," at Felixstow 

 and Sutton in Suffolk, and in the Newer Pliocene, " Fluvio-marine," 

 or " Mammaliferous Crag" in various localities near Norwich and in 

 Suffolk. I shall now endeavour to ascertain what this species is ; 

 and, as I consider that the question is one of considerable import- 

 ance, as a turning-point upon which the independent character of 

 the British Pliocene fauna hangs, — that is to say, whether it is di- 

 stinct or merely a long-lived offset from the Miocene, — I shall not 

 hesitate to enter at length upon the details calculated to throw light 

 upon the subject. 



Professor Owen is the only English palaeontologist who has under- 

 taken to identify and describe in connexion all the Mastodon-remains 

 of the Crag, which he has done very fully in his valuable work ' On 

 the British Fossil Mammalia,' published in 1846. He there designates 

 the species Mastodon angustidens or Mastodonte a dents etroites 

 of Cuvier ; and gives as synonyms, in his opinion, M. Ar'vernensis of 

 Croizet and Jobert, and M. longirostris of Kaup. He heads the 

 chapter with a woodcut of the upper and lower jaws of the Eppelsheim 

 M. longirostris, after Kaup, under the w^umto^Mastodon angustidens ; 

 and in his description of the dentition of M. angustidens in the 

 * Odontography *,' he draws his details of the various teeth indif- 

 ferently from the three nominal species above mentioned, namely, M. 

 angustidens, M. longirostris, and M. Arvernensis. In his memoir on 

 the Crag Mammalia, contained in the 47th number of the * Quar- 

 terly Journal,' published in August of the present year, he reiterates 

 the opinion that Mastodon angustidens and Mastodon longirostris 

 are synonyms of the English Crag species. Any opinion emanating 

 from so distinguished a palaeontologist as Professor Owen, and repeated 

 by him after mature study, at various intervals, between 1843 and 

 1856, must necessarily carry great weight with it. The first point, 

 therefore, to determine is, what is the species to which Cuvier' s name 

 of M. angustidens is legitimately applicable. 



{Mastodon angustidens?) — The fluviatile or lacustrine Molasse of 

 the basin of the Sub-Pyrenees has from a very remote time been 

 worked, at Simorre, by mines for what was called the *' Turquoise 

 de nouvelle Roche, ""^ this substance being the ivory of Mastodon- 

 tusks chiefly highly injected with a metallic infiltration, so as to 



* Op, cii, p. 619 et seq. 



