GEOaEAPHT OF THE MALAY AECHIPELAGO. 181 



than one in the latter. Yet of the comparatively ricli insect-fauna 

 of Madeira, 40 per cent, are continental species ; and of the flower- 

 ing plants more than 60 per cent. The Canary Islands offer 

 nearly similar results. Nothing but a former connexion with the 

 Continent will explain such an amount of specific identity (the 

 weight of which will be very much increased if we take into account 

 the representative species) ; and the direction of the Atlas range 

 towards Teneriffe, and of the Sierra Nevada towards Madeira, are 

 material indications of such a connexion. 



The Gralapagos are no further from South America than Ma- 

 deira is from Europe, and, being of greater extent, are far more 

 liable to receive chance immigrants ; yet they have hardly a species 

 identical with any inhabiting the American continent. These 

 islands therefore may well have originated in mid-ocean ; or if 

 they ever were connected with the mainland, it was at so distant 

 a period that the natural extinction and renewal of species has left 

 not one in common. The character of their fauna, however, is more 

 what we should expect to arise from the chance introduction of a 

 very few species at distant intervals ; it is very poor ; it contains 

 but few genera, and those scattered among unconnected families ; 

 its genera often contain several closely allied species, indicating 

 a single antitype. 



The fauna and flora of Madeira and of the Canaries, on the other 

 hand, have none of this chance character. They are comparatively 

 rich in genera and species ; most of the principal groups and 

 families are more or less represented ; and, in fact, these islands do 

 not differ materially, as to the general character of their animal and 

 vegetable productions, from any isolated mountain in Europe or 

 North Africa of about equal extent. 



On exactly the same principles, the very large number of species 

 of plants, insects, and birds, in Europe and North America, either 

 absolutely identical or represented by very closely allied species, 

 most assuredly indicates that some means of land communication 

 in temperate or sub-arctic latitudes existed at no very distant geo- 

 logical epoch ; and though many naturalists are inclined to regard 

 all such views as vague and unprofitable speculations, we are 

 convinced they will soon take their place among the legitimate 

 deductions of science. 



Geology can detect but a portion of the changes the surface of 

 the earth has undergone. It can reveal the past history and mu- 

 tations of what is now dry land ; but the ocean tells nothing of her 

 bygone history. Zoology and Botany here come to the aid of 



