220 GLIMPSES OF NATURE. 



European origin. Then also, on such detached islands, 

 we cannot expect to find native quadrupeds or frogs ; 

 for these animals will not face and brave a long swim 

 in the sea. In a word, it is precisely those animals 

 and plants which have ways and means of conveyance 

 over tracts of sea which people these distant islands, 

 and come to live and flourish thereon. 



Very different is the case with our continental 

 islands. Here, the animals and plants are those of the 

 adjacent mainland, altered and modified only in so far 

 as the length of the separation of the islands indicates 

 and allows. Our British animals and plants are those 

 of the Continent, and the life of Trinidad is that of 

 South America, because there has been no time, practi- 

 cally, for change. But in Madagascar, Australia, and 

 New Zealand, as islands long separated, each from 

 its mainland, we find living things utterly unlike the 

 greater land-mass from which each island was derived. 

 Thus it is that together geology and biology teach 

 us much about islands of which geography takes no 

 heed. 



