To Charles Lyell [1 November 1849]1
[Down]
Thursday
My dear Lyell
I have been deeply interested in your letter, & so far at least worthy of the time it must have cost you to write it.— I have not much to say: I look at the whole question as settled, Santorin2 is splendid; it is conclusive—it is perfect.— You have read Dufrenoy3 in a hurry, I think, & added to difficulty; it is the whole hill or “colline” which is composed of tuff with cross stratification; the central boss or “monticule” is simply trachyte.— Now I have described one tuff crater at Galapagos (p. 108).4 which has broken through a great solid sheet of basalt; why should not an irregular mass of trachyte have been left in middle after the explosions & emission of mud which produced the overlying tuff— Or again I see no difficulty in a mass of trachyte being exposed by subsequent dislocations & bared or cleaned by rain.— At Ascension, p. 40, subsequent to the last great aeriform explosion, which has covered the country with fragments, there have been dislocations & a large circular subsidence.— As far as size of Astroni5 is concerned it is nothing— do not quote Banks’ cove (for there has been some denudation there) but the “elliptic one”6 (p. 105) which is 1500 yards ( of naut: mile) in internal diameter, & therefore larger than Astroni; & is the very one, the inclination of whose mud=streams or tuff strata I measured (before I had ever heard the name Dufrenoy) & found varying from 25o to 30o.—
Albemarle Isld instead of being a Crater of Elevation as Von Buch foolishly guessed7 is formed of 4 great sub-aerial, basaltic volcanos, (p. 103) of one of which, you might like know, the external diameter of the summit or crater was above 3 nautical miles— There are no “Craters of Denudation” at Galapagos;.
I hope you will allude to Mauritius;8 I think this is the instance on largest scale of any known,—though imperfectly known. If I were you, I wd give up consistency (or at most only allude in note to your old Editions) & bring out the Craters of Denudation as a new view which it essentially is, & you cannot, I think, give it prominence as a novelty, & yet keep to consistency & passages in old Editions.— I shd. grudge this new view being smothered in your Address, & shd. like to see a separate Paper.—9
The one great channel to Santorin & Palma &c. &c.—is just like the one main chanel being kept open in atolls & encircling barrier reefs, & on same principle of water being driven in, through several shallow breaches.—
I of course utterly reprobate very wild notion of circular elevation: it is a satisfaction to me to think that I perceived there was a screw loose in old view, & so far I think I was of some service to you.—10
Depend on it, you have for ever smashed, crushed & abolished Craters of Elevations.— There must be Craters of engulfment & of explosion mere modifications of craters of Eruption—but Craters of Denudation are the ones which have given rise to all the discussions
Ever yours | C. Darwin
Pray give my best thanks to Lady Lyell for her translation11 which was as clear as daylight to me, including “leglessness”
I shall be up on Wednesday12 & want to speak one word to you about Royal Medals,13
Footnotes
Bibliography
Buch, Leopold de. 1836. Description physique des iles Canaries, suivie d’une indication des principaux volcans du globe. Translated by C. Boulanger. Paris: F. G. Levrault.
Lovén, Sven. 1844. Ny art af Cirripedia [Alepas squalicola]. Öfversigt af Kongelige VetenskapsAkademiens Foärhandlingar 1: 192–4.
Volcanic islands: Geological observations on the volcanic islands, visited during the voyage of HMS Beagle, together with some brief notices on the geology of Australia and the Cape of Good Hope. Being the second part of the geology of the voyage of the Beagle, under the command of Capt. FitzRoy RN, during the years 1832 to 1836. By Charles Darwin. London: Smith, Elder & Co. 1844.
Summary
Discusses CL’s refutation of CD’s concept of "craters of elevation" and CL’s new concept of "craters of denudation". Mentions examples of such craters. Admits that his own concept of these craters was unsatisfactory. Urges CL to publish article ["On craters of denudation", Q. J. Geol. Soc. Lond. 6 (1850): 207–34].
Letter details
- Letter no.
- DCP-LETT-1264
- From
- Charles Robert Darwin
- To
- Charles Lyell, 1st baronet
- Sent from
- Down
- Source of text
- American Philosophical Society (Mss.B.D25.83)
- Physical description
- ALS 6pp
Please cite as
Darwin Correspondence Project, “Letter no. 1264,” accessed on 23 May 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-1264.xml
Also published in The Correspondence of Charles Darwin, vol. 4