To C. G. Ehrenberg 5 September 
Down near Bromley Kent
I waited until I had a packet ready, before writing to thank you much for the copies of your communications to the Berlin academy & for your obliging letters, for which I feel truly thankful: I have at last received the first letter you wrote.—1 Dr Hooker has taken great trouble in getting the Admiralty specimens, but he tells me he has not succeeded very well: he encloses a letter in the parcel which I yesterday forwarded to Mr Francis, with a request to him to transmit it immediately to you: not living in London made it difficult for me, on account of clearance &c. to send it direct to you via Hamburgh.— I fear my specimens will not be of much interest to you; though I have picked out from as many isolated islands, as I could: anyhow they will not give you much trouble, as they are all labelled outside: if even one contains anything to interest you, I shall be amply repaid for the little trouble it has given me to get them together.
I have enclosed a copy of a little Paper, which I thought of sending to Taylor’s Journal;2 I think it will modify some of your opinions on the origin of the Dust; its [illeg] origin you will see, has been long out of the question: what great strata, abounding with Infusoria, must be now depositing at the bottom of the Atlantic; how curious, their aërial origin! I have sent specimens from four other stations: that numbered (3) is what you have already examined. Would you kindly take the trouble, the next time you send anything to England to return me my little Paper; & if you will send me any Abstract of the contents of packets 184.108.40.206. I wd allude to them in my Paper, before publishing it; if you will refer to the Latitudes & Longitudes, I shall know which packet is which.
Might I beg, as a great favour, that you would just look at the specimens of a white deposit which is of vast extent in Patagonia, between the fossiliferous tertiary strata & the overlying gravel: I have not seen any deposit quite like it & am very curious to know its nature, as I am now drawing up a short volume on the geology of S. America.—
Have you yet had time to look at any of the Pampas clay; M: Al: d’Orbigny considers it due to a debacle & of some considerable antiquity; I, on the other hand, cannot doubt that it is a slow, estuary deposit, contemporary with recent species of Mollusca, but with extinct species of Mammifers: would the Infusoria throw any light on this?3 I shd be most grateful for any such information; should you look at the specimens, which I before sent you, under this point of view, those from the central parts of the basin, would be the most instructive; namely from the tooth of the Mastodon of the Parana, or from any of the bones from the Uruguay or Banda Oriental.—
With my sincere thanks for the great honour you have done me, in the manner in which you have referred to me,4 I have the pleasure to remain. Your’s faithfully & obliged | Charles Darwin.
Might I take the liberty of asking you, the next time you see Dr E. Dieffenbach, to tell him, that I earnestly beg him to be so good, as immediately to make enquiries, about the Copper-plate, &c &c & copy of the German Edit: of my Journal, which I have not received, & am very anxious about.—
I hope you will accept from me, a copy of my small volume on Coral Reefs, which I have directed my Book-seller to send to the care of Mr Francis, for you.—
Has at last received first letter CGE wrote.
More specimens being sent.
Sends his sketch of paper ["Fine dust in the Atlantic Ocean" (1846), Collected papers 1: 199–203].
D’Orbigny considers Pampas clay deposit result of debacle. CD cannot doubt it is slow, estuary deposit. Would be grateful for information on this point.
- Letter no.
- Darwin, C. R.
- Ehrenberg, C. G.
- Sent from
- Source of text
- Museum für Naturkunde, Humboldt Universität, Berlin
- Physical description
Please cite as
Darwin Correspondence Project, “Letter no. 775,” accessed on 19 February 2017, http://www.darwinproject.ac.uk/DCP-LETT-775