Sir H. H. Hoxvorth — Geological History of tlie Baltic. 451 



II. — The Recent Geological Histoky op the Ealtic and Scandi- 

 navia AND its importance IN THE PoST-TeRTIAET HiSTOEY OP 



Westeen Eueope. 

 By Sir Heney H. Howokth, K.C.I.E., F.K.S., F.S.A., F.G.S. 

 {Concluded from the September Number, p. 409.) 



LET us now turn to the lessons presented by the Mollusca found in 

 the raised"beach.es of Norway and Western Sweden. 



Milne-Edwards was the first to discriminate the European 

 molluscan fauna into geographical provinces. This he did in 

 a paper in the Ann. Sci. IXat., 1838, p. 10. He separated our 

 European seas into two provinces, which he called the Scandi- 

 navian and the Celtic. The latter included the English Channel, 

 the coast-lands from Ireland to Gibraltar, and those of the 

 Mediterranean. 



S. P. Woodward, in his Manual of the Mollusca (1851-6), pt. iii, 

 ch. ii, "Geographical Distribution," pp. 357-61, 1856, makes tlie 

 Eaeroe and Shetland Islands and the coast of Norway from the JSTorth 

 Cape to the Naze a part of his '■'■Boreal province" (ii, p. 357) and 

 leaves the British Islands, Denmark, Southern Sweden, and the 

 Baltic in Milne-Edwards' Celtic province (iii, p. 359).^ 



The coasts southwards from the English Channel to the Canary 

 Islands, and those of the Mediterranean, S. P. Woodward named 

 the Lusitanian province (iv). These names have maintained their 

 place. To these provinces has been added an Arctic one, which was 

 apparently first suggested by S. Loven in 1896. The names were 

 accepted by the elder Sars, who, however, limited them ; thus the 

 Arctic province with him comprised only the circumpolar area 

 bounded by the Arctic Circle. The Boreal region he extended from 

 the Arctic Circle to Cape Finisterre, in about lat. 48°. South of this 

 and including the west coast of France, Spain, Portugal, the 

 Mediterranean, the Azores, and the north-west coast of Africa to the 

 Canaries he included in his Lusitanian region. The younger Sars 

 in his fine work on the Arctic fauna of Norway altered the boundary 

 of his father's Arctic province so as to include the Lofoten Islands. 

 His new boundary passed through tlie North Cape. He justified 

 the diversion of the line in the latter place because of the Gulf 

 Stream, which causes a great difPerence between the east and west 

 coasts of that promontory, thus creating a similar frontier to that 

 caused by Cape Cod in North America. 



These divisions (like all classifications of natural objects) are, 

 of course, very largely arbitrary, for the different classes naturally 

 overlap. Wherever we put down our dredge in the European area, 

 or wherever we sort the shells from a raised beach, we shall meet 

 with the fact that some of the molluscs have a very elastic and 

 adaptable constitution. They can live and thrive in many varied 

 conditions if they can only get food, and we always have to be 

 careful in making general inductions from a single species or small 



^ Of 289 Scandinavian shells catalogued by Dr. Loven, 217, or 75 per cent, 

 are common to Britain. 



