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Darwin Correspondence Project

To W. E. Darwin   14 January [1881]


Jan. 14th

My dear W.

I am glad that you wish to join the Geolog. Socy, which well deserves support, as it has largely aided the magnificent progress of Geology, during the last 12 century.1

I have written for Certificate & will take all proper steps.—2 The Leslie Stephen judgment will be sent you— very kind note from him: & I shall act implicity on his advice.—3

Mr Ruck is positive about sheep & cattle grazing on steep slopes always in horizontal lines, & he does not believe that the slope at bottom of valley would ever influence them.4 But it seems not improbable to me, that if a sheep or several first grazed, walking at the foot a steep slope & cleared the ground, or as far as it could reach; it would ascend & if it cropped all the pasturage on the next stage above it would be compelled to travel parallel to the bed of the valley.— If you visit again the spot with ledges extending parallel to the valley at about angle of 7o, keep this notion in your mind. This action would occur only when a slope abutted on a nice level bed of valley. George & Frank think that sheep have very slightly impressed sides of Cudham valley in horizontal lines; but why they shd elect to walk often along the same line I cannot imagine.5

I have been working at some of your materials about mould & furrows, & your facts have proved very useful; but I think that I shall be able to give only a few probable conclusions.—6

Do not think of ledges till weather becomes niceish. It will not do to look for acacia petioles till frost quite goes & ground is soft.— Remember about dipping the buried ends for about 110 of inch into ink. Collect all which are fairly within holes, not rejecting those which has been doubled. The doubling is new to me.—7

Your affectionate Father | C. Darwin

Bare places, such as walks, are best for objects drawn into burrows.—


CD prepared a certificate for William’s election to the Geological Society of London (see letter to T. H. Huxley, 22 January 1881).
See letter from Lawrence Ruck, 12 January [1881]. CD was trying to determine whether worms had played a role in the formation of horizontal ledges on steep grassy slopes; a common explanation for these ledges was grazing animals (see Earthworms, pp. 278–83).
George Howard Darwin and Francis Darwin. Cudham Valley was about a mile from Down House.
See Correspondence vol. 28, letter from W. E. Darwin, 31 December [1880] and n. 3.
In Earthworms, pp. 81–2, CD discussed whether leaves and petioles were drawn into burrows by worms by their base or apex; he noted that some of the petioles of Robinia pseudo-acacia were doubled up.


Earthworms: The formation of vegetable mould through the action of worms: with observations on their habits. By Charles Darwin. London: John Murray. 1881.


Discusses earthworm activity

and animal grazing on slopes.

Letter details

Letter no.
Charles Robert Darwin
William Erasmus Darwin
Sent from
JA 14 81
Source of text
DAR 210.6: 171
Physical description
ALS 4pp

Please cite as

Darwin Correspondence Project, “Letter no. 13013,” accessed on 15 September 2023,