1899.] THE MICE or ST. KILDA. 85 



I suppose, be contended by anybody, so that the question iu reality 

 resolves itself into one dealing with the time at which such a 

 connection existed, and whether it has been sufficiently recent to 

 allow of a passage aloug it of such a presumably recent mammal as 

 a Mouse. Although we canuot expect to decide such questions 

 from a mammalian pomt of view alone, it is profitable to rememb r 

 that such " an old land extension connecting Greenland, Spitz- 

 bergen, and Scandinavia with iScotlaud and Ireland" is relied u])on 

 by the Editors of the recently published second edition of the 

 ' Cybele Hibei'uica ' (Introduction, pp. li & lii) as the only reasonable 

 explanation of the presence in Ireland, and undoubtedly native 

 there, of three plants of Korth-American habitat, two of which 

 are unknown in Continental Europe ; nor would there seem to be 

 any better explanation forthcoming to account for our share in 

 Ireland of certain Invertebrates which are indistinguishable from 

 North-American forms ^ 



Similarly Mr. A. H. Keane ", although writing on a widely 

 different subject, regards the "submarine bank uhich stretches 

 from Scotland through the Faroes and Iceland to Greenland " as 

 representing " a vanished Continent of great age, which would 

 appear to have still formed dry land in late Tertiary times." 



But the present paper deals not with the question of a submerged 

 Euro-xlmerit-an Continent, but with the Mice of St. Kilda, and I 

 must content invself with pointing out in conclusion that the recent 

 exploring expedition to Eockall ^, the most westerly rock-islet off 

 the European Continent, found that when trawling at a distance 

 of about 15 miles south of that rock, " the water shoaled to 

 80 fathoms, and there was brought up in the bag a most unexpected 

 assortment of shallow-water sbells, evidently long since dead. 

 Amongst these were several kinds of Pecten, Venus casina, V. fasci- 

 ata, Mytilus modiolus, &c." In the words of the Eev. W. S. Green, 

 "Hovi', under present conditions, such shells could be found living 

 anywhere on the bank \^as difficult to understand. It would seem 

 to afford the strongest confirmation to the theory that the time is 

 not so very loug distant when there was more land, with a shallow 

 coast-line, and possibly extensive sand-banks, where now the 

 pinnacle of Eockall is the only speck acting as a memorial stone 

 to what tradition has called the ' Sunken Land of Buss.' After 

 the shallow sand-banks had A'anished, these mollusks may have 

 accommodated themselves to a deeper sea than is usual for such 

 organisms to live in, and it may be that it is only now that the 

 conditions are becoming too severe for their further existence. 

 There is, of course, the possibility that these shells may have come 

 from the bottom of icebergs which had grounded in Greenland or 

 Spitzbergen bays, but I doubt if in times sufficiently recent such 

 bergs have visited the position occupied by Eockall, and therefore 

 the former theory seems the more probable. 



1 See ' Irish Naturalist,' iv. jjp. 25, 122 ; vi. pp. 225, 257. 



- ' Ethiiulogy,' 189(5, p. 2:;i. 



^ See Trans. E. I. Acad. vol. xxsi. pt. 3, pp. 45-46 (1897). 



