My dear Hooker

It w^d be a very great pleasure to me if I c^d think that my letters were of the least use to you. I must have expressed myself badly for you to suppose that I look at islands being stocked by occasional transport as a well established hypothesis:¹ we both give up creation & therefore have to account for the inhabitants of islands either by continental extensions or by occasional transport; now all that I maintain is that of these two alternatives, one of which must be admitted notwithstanding very many difficulties, that occasional transport is by far the most probable. ²

I go thus far further that I maintain, knowing what we do, that it w^d. be inexplicable if unstocked isl^ds were not stocked to certain extent at least, by these occasional means.—³

European birds are occasionally driven to America but far more rarely than in the reverse direction: they arrive viâ Greenland (Baird): yet a European lark has been caught in Bermuda.⁴ By the way you might like to hear that European birds regularly migrate, viâ the Northern Islands, to Greenland.⁵

About the erratics in the Azores see Origin p. 393: Hartung c^d hardly be mistaken about granite blocks on a volcanic island.⁶

You must understand that I do not know, only suppose, that Beatson’s bird was a Wader.⁷

I do not think it a mystery that birds have not been modified in Madeira. Pray look at p. 422 of Origin.⁸ You w^d not think it a mystery if you had seen the long lists which I have (somewhere) of the birds annually blown, even in flocks, to Madeira. The crossed stock would be the more vigorous.—⁹

Remember if you do not come here before Nottingham, if you do not come afterwards I shall think myself diabolically ill-used.¹⁰

yours affectionately | Ch. Darwin

P.S. Ought you not to measure from the Azores, not to Newfoundland, but to the more Southern & temperate States?¹¹