THE BEGINNINGS OF SPRING. 17 



to regions which were made more fit for them by the 

 change of climate due to tlie glaciating conditions. 

 Thus the arbutus, the Mediterranean heath, the various 

 warm types of saxifrages, of butterwort, and of spurge, 

 must hive had a range from Killarney and Cornwall to 

 the Pyrenees, the Apennines, and Crete. It is notice- 

 able, too, that according to the map recently published 

 by Dr. Geikie, the south-west of Ireland and England 

 arc just the parts of Britain which escaped glaciation 

 during the height of the great ice age. 



Very possibly, however, these warmer plants may at 

 first have been driven quite southward, beyond the 

 existing limits of Britain, but may afterwards have 

 moved northward again as the ice melted. When the 

 connecting lands were washed away by the waves, or 

 submerged by alterations of level, the arbutus, the lo- 

 belia, and the scented heath would be stranded, so to 

 speak, in a few warm corners of England, Wales, or 

 Ireland, and would be separated by many miles from all 

 other specimens of their race elsewhere. In some cases, 

 no doubt, they would be killed off by the intrusive 

 Scandinavian forms, which always show a singular 

 power of living down all opposition ; and as still warmer 

 types would finally occupy the lowlands of southern 

 France, when the ice age was quite over, it happens 

 now that these insulated plants live in the mountain 

 districts only — the Pyrenees, Auvergne, and the Me- 

 diterranean islands, as well as in the hill regions of 

 Kerry and Cornwall, The warmth derived from the 

 Gulf Stream and the insular position has put the west 

 coasts of our islands on a practical equality with moun- 

 tain-countries many degrees south of them. The same 

 I C 



