RECORD: Darwin, C. R. Geological diary: Falkland Islands. (3.1834) CUL-DAR32.151-152 Transcribed by John van Wyhe and Kees Rookmaaker (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed from the microfilm by John van Wyhe and Kees Rookmaaker, corrections against the manuscript and editing by van Wyhe 7.2010. 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.

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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.


151

19. —

1834. March. E. Falkland Islands

Specimens & Information from the Adventure.

Cape Meredith. the SW point of the western islands is composed of quartz 1890, with the interstices filled with white powder: it is interesting finding this curious rock at the two very opposoite points of the group. —

New Island. is still more to the West

1886: 1887. 1888. are specimens of granular quartz rock, showing a gradation in impurities, thet were probably overlie. (1889) 1889 for it forms the lowest part of the island; this specimen is of so coarse a nature, that excepting from analogy I should have supposed it to have been of mechanical origin. —

All the S. Islands, are of more or less impure. granular quartz rock. —

At White Rock. Harbor. the quartz is much more compact & crystalline (a). but yet perceptibly granular; pure & quite white. — some less so. —

Port Egmont. — the most general rock is a hard. compact dark brown. very micaceous. sandstone 2058 (or one of the transition rock): it alternates with darker colored beds; & is much divided by strata: these dip to the NW. — in some specimens. the rock from its laminated character had very much the appearance of sandstone. —

West point. the NW extremity of W island. — the most prevalent variety is a tolerably pure, more or less hard, granular quartz Rock; there is some ferruginous, some with white powder in the interstices, & a good deal with the black specks of imperfect mica. —

151 verso

(a) At S. Carlos Bay. granular quartz. with white interstitial particles. —

152

1834. Falkland Islands

It is remarkable that the beds at this West end dipped to the East at an angle of 15°: we have seen on North side of Berkeley S. [its] dip to the South.— & they inform me that on the South side, all the beds seem to dip to the North.—

longer axis of S by S&W

My data are not certain enough to establish this curious fact: — All these specimens & notes were collected by Mr Kent, surgeon of the Adventure.—1

It is interesting finding the rocks of so precisely the same mineralogical nature over a district of about 150 by 60 miles in extent. —

(a) A box of pebbles of all sizes, (from walnut to hens-egg) was brought me from the beach in White Rock Harbor in North part of Falkland Sound; out of these I recognized 26 as certainly belonging to the great Patagonian shingle bed.: 38 certainly Falkland Island & nearly an equal number as these last about which I could not feel certain.—

Amongst the Patagonian pebbles, there was one of the often mentioned, "St Julian yellow-porphery", the others were chiefly white felspathic porphery, with white crystals of felspar, similar to what are found on plains of S. Cruz. — The original parent rock is in all probability at least 500 to 600 miles distant from these pebbles.— even the coast of Patagonia 400 miles.—

This is more striking if we suppose pebbles the size of Hens egg in the London basin to come from the Pyrenees or Northern part of the Appennines.

1 William Kent joined the expedition as Assistant surgeon in September 1833. Darwin refers to the Beagle's tender on the second voyage, Adventure, not the ship of the same name under Captain King of the first voyage.

longer axis of S by S&W] added pencil in margin.

soundings agate pebbles.] added pencil in margin.

152 verso [not microfilmed]

(a) Some few rather larger


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Citation: John van Wyhe, editor. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)

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