28 F. W. Harmer — The Coralline Crag Molluscan Fauna. 



The Southern character of the Molluscan fauna of the Coralline 

 Crag and its exceedingly close resemblance to that of the Mediter- 

 ranean is much more clearly shown when we take its abundant 

 shells only as the basis of our analysis. Omitting from Mr. Wood's 

 catalogue varieties, and those forms which are represented by unique 

 specimens only, or which are very rarely met with, we have about 220 

 species which may be regarded as the representative shells of the 

 formation. Of these 82, or about 37 per cent., are not, according to 

 Mr. Wood, known to be living, and seven others may be, for our 

 present purpose, regarded as extinct, as they have ceased to exist in 

 European seas, and are only now found in distant parts of the world. 

 Of the 132 species remaining, 119 occur in the Mediterranean at 

 the present day, and twelve others in what Dr. Gwyn Jeffreys 

 has called the West European area — that is, along the Atlantic coasts 

 between the Straits of Gibraltar and the Euglish Channel — provinces 

 which he saj's cannot be regarded as zoologically distinct. There 

 is thus only one among the characteristic Mollusca of the Coralline 

 Crag, viz. Buccinum (Buccinopsis) Dalei, which does not live in 

 seas to the south of the British Islands, and this species cannot be 

 regarded as undoubtedly boreal, for it is given by MM. Dollfus and 

 Dautzenberg, with a (?) however, as occurring in the Miocene beds 

 of Touraine. 1 Mr. Wood, analyzing the entire list of Coralline 

 Crag shells, gives 20 as British and not Mediterranean ; but of these, 

 15 are very rare, and the others, with the exception of the species 

 just named, are West European. The close connection between the 

 fauna of the Coralline Crag and that of the Mediterranean is further 

 shown by the fact that more than 30 of the extinct species of the 

 former are said to occur either in the Pliocene beds of Monte Mario, 

 near Home, 2 or in those of Biot, near Antibes, in the South of 

 France. 3 As to the Monte Mario beds, Sig. Ponzi and Meli remark 

 that their Molluscan fauna would be identical with that of the 

 Mediterranean at the present day were it not that some species have 

 emigrated and some have become extinct. Out of 396 species of 

 Mollusca found at Monte Mario, given in a list published by Cav. 

 Zaccari, 4 more than 150 occur also in the Coralline Crag, a larger 

 number than is common to the latter deposit and the Diestien 

 beds of Belgium, contemporaneous deposits of the Anglo-Belgian 

 Basin not more than 150 miles apart. 



These facts — the close correspondence between the recent Molluscan 

 fauna of the Coralline Crag and of certain Italian Pliocene beds 

 with that now living in the Mediterranean and the West European 

 areas, and the resemblance of these deposits, palaeontologieally, to 

 each other — seem to point, not merelj' to the conclusion that there 

 must have been free and direct communication between the sea of 

 the Coralline Crag and the Atlantic, but also that at some period 



1 Etude preliminaire des coquilles fossiles des Faluns de la Touraine. Eennes : 

 Paris (1886). 



3 Ponzi and Meli, Mem. E. Accad. dei Lincei, ser. 4, vol. iii, p. 672 (1887). 



3 A. Bell, Catalogue des Moll. Foss. des Marnes Blues de Biot, pres Antibes: 

 Journ. de Conch. Paris (1870). 



4 Zaccari, Catalogo dei Fossili del Monte Mario, Collezione Eigacci. Eoma. 



