and bones whenever you have done with them; but do not hurry.
You have hit on the exact plan, which, on the advice of Lyell, Murray, etc., I mean to follow--viz., bring out separate volumes in detail--and I shall begin with domestic productions; but I am determined to try and [work] very slowly, so that, if possible, I may keep in a somewhat better state of health. I had not thought of illustrations; that is capital advice. Farewell, my good and admirable agent for the promulgation of damnable heresies!
LETTER 86. TO L. HORNER. Down, December 23rd [1859].
I must have the pleasure of thanking you for your extremely kind letter. I am very much pleased that you approve of my book, and that you are going to pay me the extraordinary compliment of reading it twice. I fear that it is tough reading, but it is beyond my powers to make the subject clearer. Lyell would have done it admirably.
You must enjoy being a gentlemen at your ease, and I hear that you have returned with ardour to work at the Geological Society. We hope in the course of the winter to persuade Mrs. Horner and yourself and daughters to pay us a visit. Ilkley did me extraordinary good during the latter part of my stay and during my first week at home; but I have gone back latterly to my bad ways, and fear I shall never be decently well and strong.
P.S.--When any of your party write to Mildenhall I should be much obliged if you would say to Bunbury that I hope he will not forget, whenever he reads my book, his promise to let me know what he thinks about it; for his knowledge is so great and accurate that every one must value his opinions highly. I shall be quite contented if his belief in the immutability of species is at all staggered.
LETTER 87. TO C. LYELL.
(87/1. In the "Origin of Species" a section of Chapter X. is devoted to "The succession of the same types within the same areas, during the late Tertiary period" (Edition I., page 339). Mr. Darwin wrote as follows: "Mr. Clift many years ago showed that the fossil mammals from the Australian caves were closely allied to the living marsupials of that continent." After citing other instances illustrating the same agreement between fossil and recent types, Mr. Darwin continues: "I was so much impressed with these facts that I strongly insisted, in 1839 and 1845, on this 'law of the succession of types,' on 'this wonderful relationship in the same continent between the dead and the living.' Professor Owen has subsequently extended the same generalisation to the mammals of the Old World.")
Down, [December] 27th [1859].
Owen wrote to me to ask for the reference to Clift. As my own notes for the late chapters are all in chaos, I bethought me who was the most trustworthy man of all others to look for references, and I answered myself, "Of course Lyell." In the ["Principles of Geology"], edition of 1833, Volume III., chapter xi., page 144, you will find the reference to Clift in the "Edinburgh New Phil Journal," No. XX., page 394. (87/2. The correct reference to Clift's "Report" on fossil bones from New Holland is "Edinburgh New Phil. Journal," 1831, page 394.) You will also find that you were greatly struck with the fact itself (87/3. This refers to the discovery of recent and fossil species of animals in an Australian cave- breccia. Mr. Clift is quoted as having identified one of the bones, which was much larger than the rest, as that of a hippopotamus.), which I had quite forgotten. I copied the passage, and sent it to Owen. Why I gave in some detail references to my own work is that Owen (not the first occasion with respect to myself and others) quietly ignores my having ever generalised on the subject, and makes a great fuss on more than one occasion at having discovered the law of succession. In fact, this law, with the Galapagos distribution, first turned my mind on the origin of species. My own references are [to the "Naturalist's Voyage"]:
Large 8vo, Murray, Edition 1839 Edition 1845
Page 210 Page 173 On succession.