My dear Sir.

I am very much obliged for your note. I was so much surprised at absence of Chthamalinæ in all Tertiary Strata & at a statement which I happened to read at same time in Bulletin: G. Soc: that Chiton had for a considerable period been found only in Silurian & Tertiary beds¹ that I was led to hazard the very foolish remark & blunder which you point out about littoral shells.² I was also in a sort of muddle for I was thinking chiefly of secondary formation whilst the case of Chthamalus applied to Tertiary Strata.— I am very much obliged for this correction.—³ With respect to ancient vars resembling recent vars, of the same species, I was aware of several cases & in my fuller M.S. I have pointed out that larger classes of varieties such as Albinoes dwarfs &^c. with land productions & monstrosities have no relation to the production of new species—⁴ Such varieties cannot be called incipient species— I ought in my abstract to have pointed out this—

I remember your remarks on non migration but I cannot say that I quite appreciate them. I entirely agree with you that difficulty of not finding intermediate fossils in number is very great, even when looking at the Geological Record, as being as imperfect as I believe—⁵ No one will think anything of my book, unless his mind leads him to put weight on the apparent explanation offered by the theory from several large classes of facts as affinities,—homologies, embryology &^c. &^c— With respect to not finding intermediate gradations, I can only repeat what I have said that it is very unlikely that a future geologist, a few million years hence will be able to prove that certain forms, which are probable varieties are really varieties by discovering the intermediate links—⁶ I wish some sound Conchologist would compare Eocene Middle Tertiary & Recent Shells with the object of seeing whether any or how many of the middle Tertiary species stood in some degree intermediate between Eocene & Recent.—

With my best thanks. Pray believe me. | Yours very sincerely | C. Darwin.

P.S. | When I think over the valid objections which may be urged against my theory—I am surprised that a few really good naturalists have been converted into my heterodox notions by my book— It took me long years before I gave up the creation view of each species.—