I. 



The Effect of the GLucial Period on the Fauna 

 and Flora of the British Isles. 



''PHE question of the extent to which the flora and fauna of Britain 

 A was driven out of the country, or exterminated duringthe Glacial 

 period is intimately connected with that of the southern limit of the 

 ice. Geologists in general seem to favour the view that plants and 

 animals were for the most part — if not entirely — expelled, and that 

 our country had to be restocked from the continent. But there are 

 several considerations which point to the possibility of the survival of 

 some part at least of the pre-Glacial inhabitants of the land. 



The ice during the Glacial period may have extended as far 

 south as the latitude of London ; very possibly it did not extend so 

 far. Our opinion as to the survival or otherwise of our flora and 

 fauna will be influenced by our view as to the southern extension of 

 the ice. Let us take the former view first. This would leave the 

 counties of Kent, Surrey, Sussex, Hants, Dorset, Somerset, Devon, 

 Cornwall, and part of Wiltshire free from ice. 



As far as space, then, is concerned, we have an area capable of 

 affording an asylum to a considerable number of our plants and 

 animals. 



If, however, the Boulder Clay was not formed beneath the ice, 

 then the latter probably did not extend so far south as the latitude of 

 London, and the area fitted to form an asylum for our pre-Glacial 

 flora and fauna increased. 



As regards climate, again, it is to be remembered that ice-sheets 

 and glaciers terminate in temperate latitudes when they do not reach 

 the sea — if the latitudes were not temperate they would not terminate; 

 and in connection with existing glaciers we find a temperate flora 

 and fauna in close proximity to the ice, as in Switzerland, the 

 Himalaya, and x\merica. Further, the limits of the ice overlap the 

 limits of temperate life ; the latter ascends beyond the termination of 

 the ice, while the former extends into the domains of the latter. Note, 

 for example, how the lines marking the northern limit of forests and 

 the southern limit of the ice overlap in North America. 



Such facts lead us to admit the probability that the climate of 

 the south of England during the Glacial period was such as to permit 



