To J. D. Hooker 30 March 
Down Bromley Kent
My dear Hooker
Many thanks for your agreeable note.— Please keep the Geograph. M.S. till you hear from me; for I may have to beg you to send it to Murray; as through Lyells intervention I hope he will publish; but he requires first to see M.S.1
I demur to what you say that we change climate of the world to account for “migration of bugs flies &c”,2 we do nothing of sort; for we rest on scored rocks, old moraines, arctic shells & mammifers.— I have no theory whatever about cause of cold, no more than I have for cause of elevation & subsidence; & I can see no reason why I shd not use cold, or elevation or subsidence to explain any other phenomena, such as of distribution.— I think if I had space & time, I could make pretty good case against any great continental changes since Glacial epoch, & this has mainly led me to give up the Lyellian doctrine as insufficient to explain all mutations of climate.—
I was amused at the Brit. Mus evidence:3 I am made to give my opinion so authoritatively on botanical matters!
I shall be very glad to see your proof-sheets.— I hope to begin printing in middle of May
As for our belief in origin of species, making any difference in descriptive work, I am sure it is incorrect.—for I did all my Barnacle work under this point of view. Only I often groaned that I was not allowed simply to decide whether a difference was sufficient to deserve a name.4
I am glad to hear about Huxley,—a wonderful man.5
Ever yours affect in Haste. C. D.
Hopes Murray will publish after seeing MS [of Origin].
Demurs at JDH’s saying that CD changes climate to account for migration of bugs, flies, etc. "We do nothing of the sort; for we rest on scored rocks, old moraines, arctic shells, and mammifers." Has given up the Lyellian doctrine as insufficient to explain all changes in climate; CD has no theory about the cause of the cold.