is chiefly to enquire in what paper he has described the Boulders on Arthur's Seat. Mr. D. Milne in the last Edinburgh 'New Phil. Journal' [1847], has a long paper on it. He says: 'Some glacialists have ventured to explain the transportation of boulders even in the situation of those now referred to, by imagining that they were transported on ice floes,' etc. He treats this view, and the scratching of rocks by icebergs, as almost absurd...he has finally stirred me up so, that (without you would answer him) I think I will send a paper in opposition to the same Journal. I can thus introduce some old remarks of mine, and some new, and will insist on your capital observations in N. America. It is a bore to stop one's work, but he has made me quite wroth.")
The article "Geology," in the Admiralty Manual of Scientific Enquiry (1849), pages 156-195. This was written in the spring of 1848.
"On British Fossil Lepadidae," 'Geol. Soc. Journ.' vi., 1850, pages 439-440.
"Analogy of the structure of some Volcanic Rocks with that of Glaciers," 'Edin. Roy. Soc. Proc.' ii., 1851, pages 17-18.
Professor Geikie has been so good as to give me (in a letter dated November 1885) his impressions of my father's article in the 'Admiralty Manual.' He mentions the following points as characteristic of the work:—
"1. Great breadth of view. No one who had not practically studied and profoundly reflected on the questions discussed could have written it.
"2. The insight so remarkable in all that Mr. Darwin ever did. The way in which he points out lines of enquiry that would elucidate geological problems is eminently typical of him. Some of these lines have never yet been adequately followed; so with regard to them he was in advance of his time.