Sir C. Lyell, while agreeing with my main argument on Man, thinks I am wrong in wanting to put him back into Miocene times, and thinks I do not appreciate the immense interval even to the later Pliocene.  But I still maintain my view, which in fact is a logical result of my theory, for if man originated in later Pliocene times, when almost all mammalia were of closely allied species to those now living, and many even identical, then man has not been stationary in bodily structure while animals have been varying, and my theory will be proved to be all wrong.

In Murchison’s address to the Geographical Society just delivered he points out Africa, as being the oldest existing land.  He says there is no evidence of its having been ever submerged during the tertiary epoch.  Here, then, is evidently the place to find early man.  I hope something good may be found in Borneo, and that then means may be found to explore the still more promising regions of tropical Africa, for we can expect nothing of man very early in Europe.

It has given me great pleasure to find that there are symptoms of improvement in your health.  I hope you will not exert yourself too soon or write more than is quite agreeable to you.  I think I made out every word of your letter though it was not always easy.—­Believe me, my dear Darwin, yours very sincerely,

ALFRED R. WALLACE.

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Down, Bromley, Kent, S.E.  June 15, 1864.

Dear Wallace,—­You must not suppose from my delay that I have not been much interested by your long letter.  I write now merely to thank you, and just to say that probably you are right on all the points you touch on except, as I think, about sexual selection, which I will not give up.

My belief in it, however, is contingent on my general beliefs in sexual selection.  It is an awful stretcher to believe that a peacock’s tail was thus formed; but believing it, I believe in the same principle somewhat modified applied to man.

I doubt whether my notes would be of any use to you, and as far as I remember they are chiefly on sexual selection.

I am very glad to hear that you are on your Travels.  I believe you will find it a very convenient vehicle for miscellaneous discussion.  With your admirable powers of writing, I cannot doubt that you will make an excellent book.—­Believe me, dear Wallace, yours sincerely,

CH.  DARWIN.

P.S.—­A great gun, Flourens, has written a little dull book against me; which pleases me much, for it is plain that our good work is spreading in France.  He speaks of the engouement about this book, “so full of empty and presumptuous thoughts.”

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Down, Bromley, Kent, S.E.  January 29, 1865.

My dear Wallace,—­I must ease my mind by saying how much I admire the two papers you have sent me.