62 MR. R. D. DARBISHIRE ON MARINE SHELLS 



southwards. Of the remaining 32 species^ the whole now 

 range considerably southward of the British Isles^ but^ as a 

 set, present a characteristically British aspect. 



The remarkable feature of the Macclesfield list is there- 

 fore to be found in the 7 species not in Prof. Forbes^s list, 

 all the rest being already well known as members of the 

 Pleistocene and recent faunas of these isles. Of these 7 not 

 one appears in Mr. M'^ Andrew's " List of MoUusca observed 

 between Drontheim and the North Cape " (Annals of Nat. 

 Hist., May 1856), nor in Danielssen's ' Zoological Notes of 

 the Scandinavian coast,' 1857, except Littorina litt oralis, a 

 shell which, from its peculiarly littoral habit and its restric- 

 tion to the fiicus-herbage of the tidal rocks, may very well 

 be absent from an extensive deposit of shingle. 



The remaining 6 are all shells of species which at present 

 reach their northern limit within the British seas extend- 

 ing on our western shores, from the Spanish province. 



Cytherea chiotie, I Cardium aculeatum (?), 



Cardium rusticum, | Area lactea, 



are characteristically shells of a Spanish or southern type. 

 The Cytherea is not now found north of Caernarvon Bay, 

 nor in the German Ocean : it is " essentially a southern 

 species." The Cardia barely frequent the coasts of Devon- 

 shire and Cornwall. Cardium aculeatum is said to have 

 been dredged ofi" Bergen ; but C. rusticum is not known 

 east of the Channel. As a matter of historical geology, the 

 Cytherea inhabited British seas during the Miocene period 

 of the Coralline Crag, but has not occurred in the Red Crag. 

 The Area occurs in both beds ; the Cardia in neither. Mr. 

 J. Smith is quoted as having found C. rusticum in newer 

 Pliocene beds in Worcestershire*. 



* It may be worth while to describe the specimens of these species. C. 

 chione, six umbonal fragments, three showing complete dentition, one less 

 complete, and two half the hinge. Three fragments from the Yentral region ; 

 all considerably worn. C. rusticum, several fragments, one showing poste- 



