RECORD: Darwin, C. R. Geological diary: "Former Lemoos." — Jan. 6th [1835]. — Lat 44°: 30'. CUL-DAR35.268-269 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. Where Marginal notes are here integrated into the text.

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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.


"Former Lemoos." — Jan. 6th [1835]. — Lat 44°: 30'

All tertiary formation, composed of layers of fine blackish grey sandstone (2468: 69) very similar, but rather coarser to those of Chili, non-calcareous specks of mica; even laminae; with lines of comminuted shells. — Here & there irregular mamillated concretion of fine grained hard calcareo sandstone: these especially contain shells & shells 2473 in a more perfect state: There are also layers of these concretions, but smaller, which affect most singular shapes: cylinders, egg-shaped, intestine-shaped & bone-shaped 2470: 71; also pebble shaped.

I noticed could not extract the Cytheraea of Chiloe specks with concentric lines & a common Cytheraea — a Turbo & a Caryophyillia &c &c. — A small patch & black glistening lignite was present. — The sandstone was crossed by veins fissures, then on each side had coked the sandstone with ferruginous matter which had penetrated the stone two or 3 inches & gave a singular banded appearance to the

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(a) As so generally the calcareo-hard sandstone nodules chiefly contain the shells. — What is the cause: Has the calcareous matter determined presence of shells? & has its solidifying power preserved them?

Did they exist when this matter was not present? — We must suppose the concretionary structure to be formed at some depth within the deposit: yet the specimen (2472) seems to show that the lamelliform corall coated & adhered to one of these concretions lying on the bottom. (The concretion was 8 or 9 inches in diameter & very irregular in outline). I cannot reconcile these views. — Perhaps strata were disposed during deposition & parts thus exposed, & subsequently recovered: —

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"Former Lemoos." — Jan. 6th. — (5

stone. — A very few siliceous pebbles: perhaps few greenstone boulders on coast from same origin: Judging from fragments there must be layer of "alluvium" with gravel on top of island. —

Dip to East ∠r 30-40°. Yet I am nearly sure, only immense masses (& faults) which had slipped from their place. —

[sketch] 1

[sketch] 2

Double elevations. V. Fig. 1 & 2. —

Formation extensive to East & little North then hills of hard rock. —

Discuss shells in concretions. — (a)

Manifestly same formation as that of Chiloe

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Citation: John van Wyhe, editor. 2002-. The Complete Work of Charles Darwin Online. (

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