5 1 o PREHISTORIC E UR OPE. 



manner the Inner and Outer Hebrides became united to tbe 

 mainland of Scotland — the country that extended between them 

 and the present shores of Eoss and Sutherland being dappled 

 with innumerable lakes, some of which were of great depth and 

 width. In short, there was a return of those geographical con- 

 ditions which we have every reason to believe characterised 

 certain Interglacial epochs. [See Plate E.] 



The Scandinavian type in the British Islands, as is well 

 known, attains its greatest development in the Scottish High- 

 lands. It is less well represented in the southern uplands of 

 Scotland, the hilly district of Cumberland, and the Welsh 

 mountains, while Ireland shows a very meagre assemblage of 

 alpine and subalpine forms. The Germanic type, on the other 

 hand, is everywhere present, overspreading the other floras, and 

 giving a general character to the vegetation. " Its scarcer forms," 

 Forbes remarks, " are of much interest, from the clear manner in 

 which they mark the progress of the flora, and the line it took 

 in its advance westwards. Thus we find a number of species 

 which are still limited to the eastern counties of England, while 

 others, which have extended over considerable tracts or into 

 several districts of England or Scotland, have not found their 

 way to Ireland. It is remarkable," he continues, " that certain 

 species of this flora, which flourish best on Limestone, such as 

 Scaoiosa columbaria, Sison amomtim, Campanula glomerata, and 

 others, are not found in the limestone-districts of Ireland, and in 

 like manner certain species, which everywhere, when found, 

 delight in sand, as Ajuga chammpitys, are also wanting in such 

 Irish localities as are best adapted for them. The fauna which 

 accompanies this flora presents the same peculiarities, and 

 diminishes towards the north and west. This is very observable 

 both among the native vertebrate and invertebrate animals. 

 Thus, among quadrupeds, the mole, the squirrel, the dormouse, 

 the polecat, and the hare of England (Lepus timidus) are con- 

 fined to the English side of St. George's Channel, not to mention 

 smaller quadrupeds. So it is also with the birds of short flight ; 

 so most remarkably, no less than half the species being deficient, 



