1 859.] LYELL'S CRITICISMS. 209 



Madeira and Bermuda Birds not peculiar. You arc right, 

 there is a screw out here ; I thought no one would have 

 detected it ; I blundered in omitting a discussion, which 

 I have written out in full. But once for all, let me say as an 

 excuse, that it was most difficult to decide what to omit. 

 Birds, which have struggled in their own homes, when settled 

 in a body, nearly simultaneously in a new country, would not 

 be subject to much modification, for their mutual relations 

 would not be much disturbed. But I quite agree with you, 

 that in time they ought to undergo some. In Bermuda and 

 Madeira they have, as I believe, been kept constant by the 

 frequent arrival, and the crossing with unaltered immigrants 

 of the same species from the main land. In Bermuda this 

 can be proved, in Madeira highly probable, as shown me by 

 letters from E. V. Harcourt. Moreover, there are ample ground, 

 for believing that the crossed offspring of the new immigrants 

 (fresh blood as breeders would say), and old colonists of the 

 same species would be extra vigorous, and would be the most 

 likely to survive ; thus the effects of such crossing in keeping 

 the old colonists unaltered would be much aided. 



On Galapagos productions having American type on view 

 of Creation. I cannot agree with you, that species if created 

 to struggle with American forms, would have to be created on 

 the American type. Facts point diametrically the other way. 

 Look at the unbroken and untilled ground in La Plata, 

 covered with European products, which have no near affinity 

 to the indigenous products. They are not American types 

 which conquer the aborigines. So in every island throughout 

 the world. Alph. De Candolle's result (though he does not 

 see its full importance), that thoroughly well naturalised 

 [plants] are in general very different from the aborigines 

 (belonging in large proportion of cases to non-indigenous 

 genera) is most important always to bear in mind. Once 

 for all, I am sure, you will understand that I thus write 

 dogmatically for brevity sake. 



VOL. II. P 



