80 



ISLAND LIFE. 



[part I, 



Antiquity of Plants as affecting their Distribution. — We have 

 already referred to tlie importance of great antiquity in en- 

 abling us to account for the wide dispersal of some genera and 

 species of insects and land-shells, and recent discoveries in fossil 

 botany show that this cause has also had great influence in the 

 case of plants. Rich floras have been discovered in the Miocene, 

 the Eocene, and the Upper Cretaceous formations, and these 

 consist almost wholly of living genera, and many of them of 

 species very closely allied to existing forms. We have there- 

 fore every reason to believe that a large number of our 

 plant-species have survived great geological, geographical, and 

 climatal changes ; and this fact, combined with the varied and 

 wonderful powers of dispersal many of them possess, renders 

 it far less difficult to understand the examples of wide dis- 

 tribution of the genera and species of plants than in the case of 

 similar instances among animals. This subject will be further 

 alluded to when discussing the origin of the New Zealand flora, 

 in Chapter XXII. 



