To Archibald Geikie 27 December [1871]1
Down, | Beckenham, Kent.
Dec. 27th
My dear Sir
I am truly obliged for your paper which I have read with greatest possible interest.2 You put whole case with admirable clearness. I did not know whether you will care to hear what I am about. I formerly observed the action of earth-worms, & lately I have ascertained the amount which they annually bring to surface & (for even figures) it is over area of 10 acres no less than 161 tons of dry earth in the finest condition for being washed away.3 This is generally perched on the blades of grass, & if long or heavy rain falls soon, it flows (as I have ascertained) a little down even a gentle slope. I can not enter here into full details.— Now some 30 years ago, when I blundered so finely over Glen Roy, I remember thinking that slopes covered with turf could not be degraded, even during thousands of years.4 This I now see is a complete error. The roots of plants which secrete so much carbonic acid, & the humic acid, are known to disintegrate some rocks,5 & then earth-worms bring the finer particles to the surface, & they will be washed a little downwards; again buried in the roots, & again brought up, & again washed a little down.— As I have been in old days a great sinner about sub-aerial denudation, it wd. please me much to throw even smallest ray of light on subject.—6 I lately thought of one great difficulty, & you refer to it; viz the persistence of ridges & furrows on old pasture lands, ploughed centuries ago.7 I remember some 40 years ago having seen such with surprise in N. Wales.—8 Have you ever observed any such cases? I want very much to know whether the ridges & furrows run down the slopes, or transversely. If up & down the slopes, all that I shd. expect would be that they would be less well defined at the lower than at the upper parts of the sloping surface. Of course you will not think of answering this note, unless you can kindly give me any information about old grass-covered ploughed land.—
I have forgotten to thank you for your volcanic paper. which I read with interest in our Journal.—9 Excepting your personal friends, I believe no one was more sorry to hear of the fever which spoiled your Italian tour, than I was, as I felt sure that you wd. have done excellent work—10
Pray believe me | Yours very sincerely | Ch. Darwin
Will you excuse me for saying how much I admire the manner in which you give fair praise to Ramsay, Croll (whose paper I formerly read) & Whitaker.11 How can Elie de Beaumont pretend to say that old tumuli & fortifications are now as steep & lofty as they once were?—12 I am trying to get observations made by Dr H. Johnson at Wroxeter, viz how much fine earth is now heaped over narrow walls.—13
Forgive me for scribbling at such length.—
Footnotes
Bibliography
Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.
Croll, James. 1868. On geological time, and the probable date of the Glacial and the Upper Miocene Period. Philosophical Magazine 4th ser. 35: 363–84; 36: 141–54, 362–86.
Earthworms: The formation of vegetable mould through the action of worms: with observations on their habits. By Charles Darwin. London: John Murray. 1881.
‘Formation of mould’: On the formation of mould. [Read 1 November 1837.] Transactions of the Geological Society of London 2d ser. 5 (1840): 505–9. [Shorter publications, pp. 124–7.]
Geikie, Archibald. 1868b. On modern denudation. Transactions of the Geological Society of Glasgow 3: 153–90.
Geikie, Archibald. 1871. On the tertiary volcanic rocks of the British Islands. [Read 5 April 1871.] Quarterly Journal of the Geological Society of London 27: 279–310.
Geikie, Archibald. 1924. A long life’s work: an autobiography. London: Macmillan and Co.
Herbert, Sandra. 2005. Charles Darwin, geologist. Ithaca and London: Cornell University Press.
Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.
‘Parallel roads of Glen Roy’: Observations on the parallel roads of Glen Roy, and of other parts of Lochaber in Scotland, with an attempt to prove that they are of marine origin. By Charles Darwin. [Read 7 February 1839.] Philosophical Transactions of the Royal Society of London 129: 39–81. [Shorter publications, pp. 50–88.]
Summary
His admiration for the papers of AG [see 8119].
Relates his recent discovery that earthworms have brought to surface no less than 161 tons of dry earth over an area of 10 acres, thus creating the conditions for significant denudation. Would welcome information about the persistence of ridges and furrows in old pasture lands ploughed centuries ago. Do they run down the slopes or transversely? Refers to [A. C.] Ramsay, [James] Croll, Elie de Beaumont, and [Henry] Johnson.
Letter details
- Letter no.
- DCP-LETT-8122F
- From
- Charles Robert Darwin
- To
- Archibald Geikie
- Sent from
- Down
- Source of text
- DAR 185: 132
- Physical description
- ALS 7pp
Please cite as
Darwin Correspondence Project, “Letter no. 8122F,” accessed on 19 October 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-8122F.xml
Also published in The Correspondence of Charles Darwin, vol. 19