To C. G. Ehrenberg 29 October 
Down. Bromley Kent
Dear & highly honoured Sir
I send you a few specimens, through Chevalier Bunsen, which possibly may interest you, as they come from volcanic islands:— I beg you to observe that I do not want any information about them for my own publications.
There is, however, two specimens from the R. Gallegos (100 miles South of the Santa Cruz) which I should be very much obliged, if you could spare time to look at them. I am extremely desirous to know, whether they contain infusoria & resemble those many specimens of the great white infusorio-pumiceous deposit of the coast of Patagonia. If so, these specimens would extend the bed 100 miles; but they interest me especially, because the Officer who has sent me these specimens, has found in this bed numerous bones of great extinct Edentata.1
Should you have time to examine this specimen, & would take the trouble to inform me of the result, might I, also, beg you to inform me, what meaning you attach to the word “Fluthgebiete,” which you use, when describing the Pampæan earth which I sent you. A French translation seems to express, that you attribute this deposit of the Pampas to a great flood or debacle; whereas I understood from your letter, that you considered it, as I do, as an estuary deposit.—2
I hope you will excuse my troubling you, & believe me dear Sir | Yours with much respect | C. Darwin
Sends specimens. Asks for information about specimens from Rio Gallegos.
What does CGE mean by the term "Fluthgebiete"?
French translation gives impression that Ehrenberg attributes Pampas deposit to debacle.
Please cite as
Darwin Correspondence Project, “Letter no. 923,” accessed on 12 February 2016, http://www.darwinproject.ac.uk/DCP-LETT-923