OCEANIC ISLANDS 35 



May 13, 1863. 



I have perfect faith in your doctrine of absence of competi- 

 tion favoring retention of continental forms on Islands, though 

 how the devil one is to reconcile that with the extraordinary 

 modifications of other continental forms on same Islands 

 passes my comprehension, except what you won't admit 

 that they were common to continent and island before 

 disjunction of latter, and the modification is of the continental 

 forms, the insular being the old original type. This is turning 

 the tables over you with a vengeance, but I will work it out 

 in spite of you. Go to weep and howl ! The Ferns of 

 Ascension and St. Helena are totally different from one 

 another and from Cameroons ; this is, or ought to be, a 

 death-blow to all aerial migration, for Ferns are notoriously 

 widely dispersed and dispersable. I wish I had never 

 wasted a thought on the stupid subject. 



May 24, 1862. 



Thanks for your exposition of your island views, 1 I think 

 I understand them precisely, my difficulty in accepting 

 them arises from the want of apparent accordance between 

 the plants common to island and continent, and what I 

 should have expected to be common. In other words, 

 migration is inadequate to explain the presence of what is 

 common to both and the absence of what is absent in one. 

 I am far from believing in ancient commotion, all I hold is 

 that in the present state of science it is to me the least 

 difficult hypothesis, though a very bad one. Cameroons 

 Mountains have shaken my faith in our having any clue to 

 ancient or modern migration as yet. We want some new 

 hypothesis, as novel as Nat. Selection, or Glacial Cold, and 

 as stupendous as Continental Connection. 



Samaden, Engadine Valley : July 10, 1862. 



This, the valley of the Inn, appears to me to combine the 

 beauty of the Tyrol with the savage grandeur of Switzerland 

 in a remarkable degree. In science I have seen little but 

 Heer's fossils, he shewed me a leaf apparently Dicotyledonous 

 from the Lower Lias in Jura, which please tell Lyell of. He 

 has a wonderful collection of fossil insects and crustaceae 



1 See Darwin's letter, M.L. i. 241. ' With respect to Island Floras, if I 

 understand rightly, we differ almost solely how plants first got there.' 



