RECORD: Darwin, C. R. Geological diary: Bay. N. of Orange bay. [2.1833] CUL-DAR34.181-182 Transcribed by Kees Rookmaaker, edited by John van Wyhe (Darwin Online,

REVISION HISTORY: Transcribed by Kees Rookmaaker, corrections and editing by John van Wyhe 4.2011. 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.

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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.


Bay. N. of Orange bay. —

Rock. generally feldspathic with few few crystals of feldspar. Sometimes slaty — Othertime with angular cleavage, showing a tendency to become columnar. — (795?)

Traversing the Hardy peninsula

Hills not lofty, become quite irregular & generally in rough paps. protruded irregularly from the outline of the hills. A slate range would appear to run in a line with Cape Weddell & bearing from West coast WNW. All the southern part would appear to be of the following description:

rocks. very various. of 5 or 6 small hills which I ascended: one was fine hornblende: — another feldspathic with crystals of feldspar & [acecular] one of hornblende. —

Another good trap (988.) with hornblende rock with much pyrite: — another hill. was greenstone

181 verso

& feldspathic rock. — The most lofty hill was slaty feldspathic rock. — cleavage running about SE by E (true). — This is very remarkable as showing the intimate relation between this rock & the slate. — NB. these hills were surrounded on all sides by the crystalline rock. —

Another hill of large size was of a most singular nature being basaltic (easily fusible) with numerous yellow crystals. & dividing into an angular small concretionary pieces: decomposing easily the detritus consisting of their pieces. rem on a large scale columnar. but not very regular — the rock very constant in character. reminded me of volcanic rock. — I have reason to believe. that

(991. —2. 3:


precisely similar rock (specimen & memory of Mr Bynoes) in the gulf of Penas: This hill. as the others is quite unconnected with all others & entirely formed of this rock. Yet the surface was covered by angular fragments of several varieties of greenstone:

There is a mass of rock lying between all these hills. & which would appear to be syenite. & resembling that on the southern arm of Beagle Channell. — The irregular form of hills, if submerged would explain the numberless islands of West coast. —

I imagine all these rocks, & the whole S. — Trap formation to be slate altered: (where the hills are conical mostly fused). — Perhaps when after all the central granite chain was upheaved. we may suppose this great attention & disturbance in

182 verso

in the slate formation:

((the quantity of pyrites in hornblende rock, accounted for by the iron formation in the slate))

Guanaco by the disjunction of alluvium in Navarin island. —

The anticlinal arches & dykes of greenstone show that since the SSW elevation there has been grand disturbance

The islands in [illeg] bay greenstone (?)

T. del Fuego. —

T. del Fuego. —] written perpendicular to other entries on the page, as a heading or title to these notes.

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