My dear M^r Darwin,

I have just received a note from a friend, who starts for Nevada, and the “far west” in the course of a day or two—¹ He is a capital geologist, and a painstaking observer of Nature, and one whom I could depend on for accurate observations. He writes as follows:— “Has M^r Darwin any special object of enquiry, or investigation out West? I shall be pleased to do what I can if he has.”

If there is any speciality you can think of and will drop me a post card I will communicate with him before he leaves. Especially anything relating to mammals or birds—either living, or preserved in the record of Geology. I may add that he is a most enthusiastic convert to, and supporter of, your theory of Natural Selection—

On my own account it may interest you to know (if you were not previously aware of the fact) that the young of the common chaffinch (Fringilla cœlebs) in its first nestling plumage almost exactly resembles the adult female of its nearest ally the brambling (F. Montifringilla) in winter plumage!

Believe me, dear M^r Darwin, | (In haste)| very faithfully yours, | Henry Reeks—

C. Darwin, Esq^re M.A., F.R.S. &c—