Geographical Distribution. 213 



faunas and floras of the world, so that merely to 

 enumerate the instances would require a separate 

 chapter. 



Furthermore, the general argument thus presented 

 in favour of descent with continuous modification 

 admits of being enormously strengthened by three 

 different classes of additional facts. 



The first is, that the correlation in question 

 namely, that between a geographically restricted 

 habitat and the zoological or botanical affinities of 

 its inhabitants is not limited to the now existing 

 species, but extends also to the extinct. That is to 

 say, the dead species are allied to the living species, 

 as we should expect that they must be. if the latter 

 are modified descendants of the former. On the 

 alternative theory, however, we have to suppose that 

 the policy of maintaining a correlation between geo- 

 graphical restriction and natural affinity extends very 

 much further back than even the existing species 

 of plants and animals ; indeed we must suppose that 

 a practically infinite number of additional acts of 

 separate creation were governed by the same policy, 

 in the case of long lines of species long since extinct. 



Thus far, then, the only answer which an advocate 

 of special creation can adduce is, that for some reason 

 unknown to us such a policy may have been more wise 

 than it appears : it may have served some inscrutable 

 purpose that allied products of distinct acts of crea- 

 tion should all be kept together on the same areas. 

 Well, in answer to this unjustifiable appeal to the 

 argument from ignorance, I will adduce the second 

 of the three considerations. This is, that in cases 

 where the geographical areas are not restricted the 



