More Letters Of Charles Darwin Volume 1 A Record Of His Work In
Chapter 402
(367/1. In a letter of July 31st, Sir J.D. Hooker wrote, "You must not suppose me to be a champion of continental connection, because I am not agreeable to trans-oceanic migration...either hypothesis appears to me well to cover the facts of oceanic floras, but there are grave objections to both, botanical to yours, geological to Forbes'.")
The following interesting letters give some of Sir Joseph's difficulties.)
Kew, August 4th, 1866.
You mention ("Journal") no land-birds, except introduced, upon St. Helena. Beatson (Introduction xvii) mentions one (367/2. Aegialitis sanctae-helenae, a small plover "very closely allied to a species found in South Africa, but presenting certain differences which entitle it to the rank of a peculiar species" (Wallace, "Island Life," page 294). In the earlier editions of the "Origin" (e.g. Edition III., page 422) Darwin wrote that "Madeira does not possess one peculiar bird." In Edition IV., 1866, page 465, the mistake was put right.) "in considerable numbers," resembles sand-lark--is called "wire bird," has long greenish legs like wires, runs fast, eyes large, bill moderately long, is rather shy, does not possess much powers of flight. What was it? I have written to ask Sclater, also about birds of Madeira and Azores. It is a very curious thing that the Azores do not contain the (non-European) American genus Clethra, that is found in Madeira and Canaries, and that the Azores contain no trace of American element (beyond what is common to Madeira), except a species of Sanicula, a genus with hooked bristles to the small seed-vessels. The European Sanicula roams from Norway to Madeira, Canaries, Cape Verde, Cameroons, Cape of Good Hope, and from Britain to Japan, and also is, I think, in N. America; but does not occur in the Azores, where it is replaced by one that is of a decidedly American type.
This tells heavily against the doctrine that joins Atlantis to America, and is much against your trans-oceanic migration--for considering how near the Azores are to America, and in the influence of the Gulf-stream and prevalent winds, it certainly appears marvellous. Not only are the Azores in a current that sweeps the coast of U. States, but they are in the S.W. winds, and in the eye of the S.W. hurricanes!
I suppose you will answer that the European forms are prepotent, but this is riding prepotency to death.
R.T. Lowe has written me a capital letter on the Madeiran, Canarian, and Cape Verde floras.
I misled you if I gave you to understand that Wollaston's Catalogue said anything about rare plants. I am worked and worried to death with this lecture: and curse myself as a soft headed and hearted imbecile to have accepted it.