Darwin Correspondence Project

Down. Bromley. Kent.

May 27th— /(56.)

Dear Sir.

I am very much obliged to you for having taken the trouble to answer my query so fully— I can now be at rest, for from what you say & from what little I remember Forbes said, my point is unanswerable. The case of Terebratula is to the point as far as it goes and is negative. I have already attempted to get a solution through geographical distribution by Dr Hooker's means, & he finds that same genera which have very variable species in Europe, have other very variable species elsewhere— This seems the general rule, but with some few exceptions— I see from the several reasons which you assign, that there is no hope of comparing the same genus at two different periods, & seeing whether the tendency to vary is greater at one period in such genus than at another period— The variability of certain genera or groups of species strikes me as a very odd fact.

I shall have no points as far as I can remember to suggest for your reconsideration, but only some on which I shall have to beg for a little further information— However I feel inclined very much to dispute your doctrine of Islands being generally ancient in comparison I presume with continents— I imagine you think that islands are generally remnants of old continents a doctrine which I feel strongly disposed to doubt— I believe them generally rising points, you, it seems think them sinking points—

With many thanks. | Yours very sincerely. | C. Darwin.