RECORD: Darwin, C. R. Geological diary: Niebla Fort. [2.1835] CUL-DAR35.348-349 Transcribed by Kees Rookmaaker, edited by John van Wyhe (Darwin Online,

REVISION HISTORY: Transcribed by Kees Rookmaaker, corrections and editing by John van Wyhe 5.2011. RN1

NOTE: This document, part of the largest scientific document composed by Darwin during the voyage of the Beagle, is written mostly in ink. Marginal notes are here integrated into the text. Darwin was in Valdivia 9-21 February 1835; see the Beagle diary, pp. 533. Darwin sometimes spelled Valdivia as Baldivia, his phonetic spelling of Spanish pronunciation. See the illustrations of Valdivia drawn by FitzRoy and P. G. King in Narrative 1.

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Reproduced with the permission of the Syndics of Cambridge University Library and William Huxley Darwin.

See the introduction to the Geological Diary by Gordon Chancellor.


Niebla Fort1

Mica slate dipped in SW by but very variable & in curves:

The modern formation entirely consists of sandstone, very soft & coarse. — in one place beds 150 ft thick. — there are no concretions, no alternations with clay. — no hard veins or plates. — In one place I found numerous imperfect fossil remains, chielfy of Mytilus Cytheraea Mytilus & Solen. I believe species which all now exist. — In another (2547: 48: 49: 50). In another layer of flattened balls of a yellow soft substance, which tas in the mouth has a curious taste. — Perhaps roots of some large Fucus such as Kelp (2551:). —

The sandstone must not always be supposed to be so coarse as in these specimens, for at Baldivia we have a much harder, purer & finer grained stone: —

I believe from mineralogical & organic difference is the imbedded remains. it is a more modern formation than that of Chiloe: — I found at the Castle of Niebla a great bed of the sandstone, traversed by an irregular one of softer sam sort. — & the whole mass divided into very regular layers which dipped at angle 45°. a sort of cleavage, viz: [sketch]

1 Darwin wrote in the Beagle diary for 18 February 1835: "I crossed over to the Fort called Niebla, which is on the opposite side of the bay to the Corral where we are at anchor. — The Fort is in a most ruinous state; the carriages of guns are so rotten that Mr Wickham remarked to the commanding officer, that with one discharge they would all fall. The poor man trying to put a good face on it, gravely replied, "No I am sure Sir they would stand two!"

348 verso

Feb. [1835] —

During a ride to the Mission of Cudico. —

Crossed much micaceous schist & the porphyritic kind — already described. =

The dip of the laminae of these rocks appears in each individual spot, but regular — but on whole no one direction can be discovered. — The dip however which is perhaps most common is to ENE?? — But the exceptions are very numerous. — The country in its outline is very irregular. — The surface, as in Chiloe, consists of beds of clays & also many pebbles of quartz. =

At Cudico we have a fine view of the Llanos, which extend to beyond Osorno. — & probably to Ch Carel Mapu. — I saw, the sandstone at Cudico, which I believe these plains are composed, it is similar to what is found at Baldivia pale colored. — earthu (ie particles of coarser size, imbedded in finer sediment & not very soft. — horizontal layer. —

I found in one locality, slate-colored porphyry, with many crystals of feldspar: there were only fragments but so numerous that the parent rock must have been near.

Soil bright red — like Valparaiso —



rounded fragments. —

I see a ma fringe of plain very common around the bases of the mica slate hills. — This to the eye has the same exact altitude with the a similar fringe described in Chiloe (altitude 60-70 ft??)

Thus we see on this W side of the continent, a similar proof of that certain elevations having existed of taken place with greater degree of so amount force leave over an great extent of coast. as plains, as an index of this existence. —

At the Plaza some low land is formed of horizontal beds of a yellowish indu hard, fine grained sandstone. —

349 verso


Peaches — standing

Strawberr Figs extending far & not & do ripen well

Olives partially ripen. —

no grapes ripen, but scarcely worth cultivating

Indian corn? I observe (poor) in Chiloe. —

Oranges. No —


(Chiloe very few peaches)

Lat. — Valdivia. — 39° — 53.

Little Indian [grits]

Officer at the Fort of Niebla:

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