1843— 1882] CONTINENTAL EXTENSION 427 



To C. Lyell. Le tter 327 



Down, July 8th [1856]. 



Very many thanks for your two notes, and especially for 

 Maury's map : also for books which you are going to lend me. 



I am sorry you cannot give any verdict on continental 

 extensions ; and I infer that you think my argument of not 

 much weight against such extensions ; I know I wish I 

 could believe. 1 



I have been having a good look at Maury (which I once 

 before looked at), and in respect to Madeira & Co. I must 

 say, that the chart seems to me against land-extension 

 explaining the introduction of organic beings. Madeira, the 

 Canaries and Azores are so tied together, that I should have 

 thought they ought to have been connected by some bank, if 

 changes of level had been connected with their organic relation. 

 The Azores ought, too, to have shown more connection with 

 America. I had sometimes speculated whether icebergs could 

 account for the greater number of European plants and their 

 more northern character on the Azores, compared with 

 Madeira ; but it seems dangerous until boulders are found 

 there. 2 



One of the more curious points in Maury is, as it strikes 

 me, in the little change which about 9,000 feet of sudden 

 elevation would make in the continent visible, and what a 

 prodigious change 9,000 feet subsidence would make ! Is the 

 difference due to denudation during elevation ? Certainly 

 12,000 feet elevation would make a prodigious change. I have 

 just been quoting you in my essay on ice carrying seeds in 

 the southern hemisphere, but this will not do in all the cases. 

 I have had a week of such hard labour in getting up the 

 relations of all the Antarctic flora from Hooker's admirable 

 works. Oddly enough, I have just finished in great detail, 

 giving evidence of coolness in tropical regions during the 



1 This paragraph is published in the Life and Letters, II., p. 78 ; it 

 refers to a letter (June 25th, 1856, Life and Utters, II., p. 74) giving 

 Darwin's arguments against the doctrine of "Continental Extension." 

 See Letters 47, 48. 



3 See Life and Letters, II., p. 112, for a letter (April 26th, 1858) in 

 which Darwin exults over the discovery of boulders on the Azores and 

 the fulfilment of the prophecy, which he was characteristically half 

 inclined to ascribe to Lycll. 



