338 ISLAND LIFE 



to show an almost perfect community with the adjacent 

 parts . of the continent in its natural productions ; and 

 such is found to be the case. All the higher and more 

 perfectly organised animals are, with but few exceptions, 

 identical with those of France and Germany ; while the 

 few species still considered to be peculiar may be 

 accounted for either by an original local distribution, by 

 preservation here owing to favourable insular conditions, 

 or by slight modifications having been caused by these 

 conditions resulting in a local race, sub-species, or species. 

 TVhp Britain is Poor in ^ijecics. — The former union of 

 our islands with the continent, is not, however, the only 

 recent change they have undergone. There is equally 

 good evidence that a considerable portion, if not the 

 entire area, has been submerged to a depth of nearly 

 2,000 feet (see Chap. IX. p. 174), at which time only 

 what are now the highest mountains would remain as 

 groups of rocky islets. This submersion must have 

 destroyed the greater part of the life of our country ; and 

 as it certainly occurred during the latter part of the 

 glacial epoch, the subsequent elevation and union with 

 the continent cannot have been of very long duration, and 

 this fact must have had an important bearing on the 

 character of the existing fauna and flora of Britain. We 

 know that just before and during the glacial period we 

 23ossessed a fauna almost or quite identical with that of 

 adjacent parts of the continent and equally rich in S23ecies. 

 The submergence destroyed this fauna ; and the perman- 

 ent change of climate on the jjassing aAvay of the glacial 

 conditions appears to have led to the extinction or 

 migration of many sjDecies in the adjacent continental 

 areas, where they were succeeded by the assemblage of 

 animals now occupying Central Europe. When England 

 became continental, these entered our country ; but 

 sufficient time does not seem to have elapsed for the 

 migration to have been completed before subsidence 

 again occurred, cutting off the further influx of jDurely 

 terrestrial animals, and leaving us without the number of 

 species which our favourable climate and varied surface 

 entitle us to. 



