RECORD: Darwin, C. R. Geological diary: Port Famine. (2.1834) CUL-DAR34.125-128 Transcribed by Kees Rookmaaker, edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)
REVISION HISTORY: Transcribed by Kees Rookmaaker, corrections and editing by John van Wyhe 3.2011. 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.
Port Famine Feb 3d  — Common rock. slate but little fissile on Port St Anna South side (slate 1790) in layers or beds
dipping running N. 71 (—23 V) W (=48°) & dip southerbly∠ 56°. — crossed by numerous other lines (forming rhomboids which run NE by E & SW by W (true). —
other N side of St Anna — exactly same dip
In the first & second little coves the direction is N. 68° W, but dip only 29°. — Here the slate is separated by many grey calcareo harder beds (1791). — I see slight flaws. here by the non-correspondence. of these beds. —
They are traversed by few narrow dykes of earthy fusible
matter. trap. (1792) — the sides of these are slightly tortuous. they cross at right angle both previous sorts of beds: in one case 2 more approximate 2 feet apart & enclosed slate — which was not altered. — they approached to each other, then separated & one died away. — In these beds there are nodules of dark calcareous rock. but they are more abundant further on & will be described. — I have shown the bed & side of creek ran about NW & SE. the creek ran about E by N & S by W — on the northern shore I was surprised to find slate, running. N 69° W but dipping to the NE at ∠ 15°. — therefore an anticlinal line runs obliquely across the creek. —
The dip continued to Rocky point, in one place traversed by vertical cleavage line running NE by E & SW by S. —
The former cleavage more resembles beds. The slate is
See Darwin's discussion of Port Famine in South America, pp. 151-2, 156, 265, 267.
here more compact & slightly calcareous (1789) it contains very numerous globular & shell shaped concretions of dark coloured limestone: in some of these impressions of siphon shaped [cornu-annonas]. — (1785—1788). —
One of these
I measured most perfect, measured in the centre. following the curvatures 21 inches short legs of siphon. 7 inches: head the of do. (& this lower limit was the rather broardest 2.7 inches. = Several of these impressions. =
Conglomerate at Cape. Remarkable;
many some blocks of do on beach here
on the salte veins ([illeg] with & across beds) of white carb of lime. — crystallized. — & nodules of iron pyrites
Feb. 7th  — The calcareous concretions are very curious shape sausage— cylinders, stalactiform. occur rather in layers.
At North side of Rocky Point, there is a coarse greenish slate (1811) passing into this greywacke (1812) with small angular fragment of green slate. — in the former there was the remains of some twelve shell.
I omitted to mention that in the slate I found a curious
thing organic remains the nature of which I am quite ignorant (1813). also saw a Nautilus such as will be mentioned at Mount Tarn. only three as large. —
If the slate is subject to stratification, we shall probably have the puzzle of long distance in direction of dip, with exact same points, high angle & no anticlinal line. —
2d the anticlinal line occurs in a valley. — hills on each side much higher. — It would however well explain form of land & hills: similarity of form of gneiss & slate. — But then it must be remembered we know there is such a thing as highly inclined original cleavage: it is strangely improbable that in the South there should be cleavage
running dipping to SSW & have stratification to SW.
Feb. 6th.  Between Port St Anna & rocky Point got following dips.
[the coastline is sketched on the left side of the page] L Rocky P. H G F E D C cx b a K St Anna P. Famine
|(d)||irregular no decided strata|
|(E)||dip NW ∠ 5. or horizontal|
|(K)||dip 78° to S or ┴ staying tortuous||78
|45 dip||North. dip 78° to S or ┴ staying tortuous|
I have only one remark to make. it is very extraordinary the anticline line being at the point where the line commences a mile or two to the mouth. Mt Phillip ([blank]) feet high. —
Mount Tarn Feb. 6th.  — The summit only shows rocks. Hence on the side of St: we have a precipitous escarpement — the rock is essentially compact coarse slate; generally blueish sometimes yellowish (1810); parting of seams ferruginous, also contains pyrites: the structure is curious, appearing generally like so many immense common balls of 3 or 4 feet diameter. round which the slate folds. — as is shown by its decomposition. — Some of the rock contains much iron. — I found in one bed not far from summit (height 2600 ft) a univalve shell & bivalve-like Terebratula which I lost. — Some of an Echinus; but these were uncommon there were however numerous fragments of impressions of a shell, somewhat resembling that found North of Pocky Point. — it was special. & flattened like a Nautilus & evidently very common. — 1809). —
It was very curious effect of snow in decomposing rock. — rubble & vegetation at foot. —
Stratification hard to be made out. The highest point dipped at ∠ 28
to a ran N & N. 62. W. — the whole ridge veined from this to 20° & more 23/39 degree less west.
I could see other escarpements to the western resembled this. Hill seemed to run NW by W & SE by E. (compass) But none of these are accentuated. —
NW by 1/2 W to NW by N
[Folio 127 missing from the original]
Feb 6th.  At foot of Mount Tarn. many boulders of western rocks at highest part of ordinary high water mark
the largest was of Hornblende rock. was a rough [illeg] with convex & rounded, mean height 4ft 6in feet. girth 24 ft. — Many were half this sum & quarter. common 2 in 3 or 2 times as large as the head. — [sketch]
In the sheltered rocks North of P. St Anna. blocks of that peculiar (NW arch of P. [Julian] an granite block girth 15 ft. mean length
2 3 ft 6 feet: [many] 2.6 feet. — Another of conglomerate nearly [illeg] size, generally very few in such these sites
Mem: Alluvial formation: Height?? Origin of Rock M. Philip
A couple of miles north of Rocky point slides nearly [vertical] (or dip northernly). (N. 65 W. comp). & nearer to same point N. 55 W. 23/32 comp. — 23/42 P. St Anna. — strata slightly [illeg]
Bivalve & shell. like a Turritella in a green [conglomerate] pebbles of quartz; blending with the slate: in [irregular] sort of masses or veins: perhaps slightly parallel to [illeg] but very obscure: (Mem argument from stones not [illeg] rounded & at high water mark must both be [illeg] on very limited sense). — Mem. Wickham [illeg]
Blocks of granite &c (2.10 1/2.1) & many other layers & [illeg] in [illeg] of hills 30 & 40 feet above sea. [illeg] Perhaps M. Phillip [illeg] (creek all run NW.) block but smally angular. — coarse hornblendic
128 verso [blank]
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