RECORD: Darwin, C. R. Geological diary: King George's Sound. (3.1836) CUL-DAR38.864-881 Transcribed by Kees Rookmaaker, edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Kees Rookmaaker, corrections by John van Wyhe 9.2009, corrections and editing by van Wyhe 9.2010. RN2

NOTE: This document, part of the largest scientific document composed by Darwin during the voyage of the Beagle, is written mostly in ink. Where pencil was used instead this is noted in the textual notes. Marginal notes are here integrated into the text. The paper size is uniform, 20 x 25.5 cm.

Editorial symbols used in the transcription:
[some text] 'some text' is an editorial insertion
[some text] 'some text' is the conjectured reading of an ambiguous word or passage
[some text] 'some text' is a description of a word or passage that cannot be transcribed
< > word(s) destroyed
<some text> 'some text' is a description of a destroyed word or passage
Text in small red font is a hyperlink or notes added by the editors.

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.


864

1

March 1836

King George's Sound

The basal rock in the whole of this neighbourhead is Granite. It varies exceedingly in its nature: the most ordinary varieties are a common grey kind, a ferruginous slightly quartzose one, & a Granite handsome stone composed of very large oblong Crystals of Feldspar, little quartz, black mica, which latter not infrequently is replaced by Hornblende. — In several places the crystals of Mica & Hornblende are very obscurely arranged in vertical planes. — sometimes the arrangement is sufficiently developed to cause the rock to wear away into coarse thick plates. — generally however the lines can only just be perceived. — I could not observe any determinate direction in the planes, & not unfrequently they were irregular & curved. — Where this structure occurs, the rock would be denominated according to Humboldt a gneiss-granite. — Indeed, when on entering the Sound in the vessel, I saw that peculiar form, of bare, smooth conical hills, appearing to be composed of great folding layers, which is found in Brazil & in the mountains of Venezuela. I at once suspected, that

865

2

K. Georges Sound

the observation by Humboldt of the frequency of this form, in hills of Gneiss-Granite, would be verifyed in this part of Australia.

The granitic rocks in parts are traversed by a multitude of veins of different varieties, some of which appear contemporaneous & others injected. There are also a great many dikes, each from 3 to 4 ft thick & composed of the same kind of a bright green greenstone, containing rather large Crystals of feldspar. (3548) Some of the dikes terminate in wedge shaped points & others send off their veins. In one point they were in such close proximity, that the Greenstone in quantity exceeded the partitions of Granite. The dikes are nearly parallel & run about E & W; this is the line direction of the point & of some small outlying rocks & islands. — This line is likewise common to several of hills & Islands

866

3

K. George's Sound

near the Sound. — Near to the settlement in Princess Royal harbor, there is another system of 6 or 8 dikes; these are about a foot wide, with a structure slightly prismatic, & are composed of a black base porphyritic with very numerous small crystals of glittering Feldspar, & some Iron pyrites. 3551 — They occur within a space of a hundred yards & run about N by E & S by W; — a direction at right angles to the last system. — Besides these I noticed several scattered dikes; also some masses of pale, colored, Porphyritic Greenstone (3552, 3553) which, I am ignorant whether they belong to the age of the dikes or of the Granites. From their containing however very heavy grains of quartz, I should suppose the latter. —

Viewing the country from an eminence, the [word deleted] hills of Granite are seen abruptly to rise out of a plain. Although the country is strictly a plain, yet from the many small valleys of excavation, it is far from level. The granitic formation is every where in the low country smoothed over by sedimentary deposits. The most abundant

867

4

K: George's Sound

kind, is of a highly ferruginous nature & finely grained; it not uncommonly contains small angular concretionary fragments of hard ferruginous sandstone; perhaps from this structure & the action of the weather the stone is sometimes honeycombed 3554 3555 (b). (b) Small quartz pebbles are here frequently imbedded in the ferruginous stones, & sometimes in numbers sufficient to make a conglomerate. In other parts, there are patches of ordinary soft sandstones, some ferruginous, others calcareous. On the South side of P. Royal Harbor soft calcareous beds are worked for Lime. —

Having given this slight sketch of the Geology of the neighbourhead, I will now particularly describe Bald Head. — This spot has long been known from the visits of the distinguished navigators (a) Vancouver, D'Entrecasteaux, Freycinet, Flinders, & King, who have all mentioned with various opinions the singularly formed calcareous bodies lying on the surface of the ground. I went in company with Capt. Fitz Roy & as we perfectly coincided in opinion

867 verso

(a) These, & all other references, are at present entirely drawn from Dr Fittons appendix to Kings Australia. —

(b) Dr Fitton discussing the calcareous Breccia of New Holland, states "that the stone of the fragments is very nearly the same with that of the cement by which they are united, — the difference consisting only in the greater proportion of sand which the fragments contain." This is precisely what has happened in this case, only that here the fragments are from a 1/4 to 1/8 in size, instead of from 1/2 to 2 inches. Dr Fitton attributes the origin of the structure to mechanical violence, during the time of deposition; he explains however the nodular forms, which are shown in Dirk Hartogs Isd to be closely connected with the occur in the same rock; are common in Bernard Isd by a sort of chemical action, which is exemplified in the preparation of the compound, of which ordinary Earthenware is manufactured. — I am strongly inclined to believe, that this latter explanation applies to both cases, when the nature of the fragments & matrix are precisely similar. the introduction of violence is perhaps necessary. — I have shown in the sandstone of New S. Wales, that ferruginous sandstone veins, which appear to be veins of segregation, like the agate was in sandstone of Chiloe, become in parts so abundant as to leave the ordinary sandstone, nearlyin the small [intestinal] spaces: a modification of some such action might produce a few separating the angular fragments from the, perhaps produce the angular brecciated structure. —

868

5

K: George's Sound

the following. may be considered our joint observations on this disputed subject. which is also the same as that arrived at by Peron — The point not visited by Peron. As it appears to me, that there is sufficient evidence to prove the origin of the strata, in which the calcareous bodies are imbedded without at first in any way noticing their presence, I shall proceed on this plan: afterwards any arguments adduced from the nature of the bodies themselves will solely come in not as the foundation but as a support of such views. —

Bald Head is a narrow steep sided ridge about 600 (?) ft high. — (a) The fundamental rock is Granite in its usual form of smooth obtuse cones. These are encased to a considerable thickness by layers of calcareous matter either pure or mixed with sandstone. Strata accumulated over narrow ridges & points must necessarily be extremely irregular in form & thickness; I was however surprised to find some inclined, with an even surface at an angle of exactly 30 degrees. In many parts scarcely any stratification could be perceived, in others seams (oblique to true strata)

which is also...by Peron.] added pencil.

but as a support of such views] 'but' in pencil.

but as a support of such views. —] added pencil.

868 verso

(a) The highest part is 700 ft. angular. measurement.

869

6

K: George's Sound

were inclined towards the hill. Degradation has in places worn the slope, even steeper, than the angle of original deposition, hence the surface shows a few irregular zigzag or waving, white line, which mark the position of the mantle shaped strata. The lowest rock, I could see, was a very compact fine grained grey or cream coloured sandstone 3533, where minute particles of transparent quartz are embedded by cemented a calcareous matter rock. From what I have said of the stratification, it is manifest that any order of superposition could be scarcely be observed. 3534 ... 3538 I believe such sandstones, others softer, yellow, & more calcareous, & yellow slightly agglutinated calcareous sand, & white calcareous, friable stone possessing an earthy fracture & layers of a hard stalactiform limestone, all alternate without any determinate order. — In one spot there was a red Calcareous sandstone. — Generally, [words deleted] whenever the white earthy calcareous rock formed the superficial stratum, its upper layer to the thickness of an inch or two gradually passed into a very solid pale brown calcareous rock 3535 3536, possessing somewhat of the

870

7

K. Georges Sound

nature of the stalactite. It may be remembered that I have made the same observation when observing the "Tosca" rock in the Provinces of La Plata, in Northern Patagonia, in the planes of St Jago & Coquimbo in Chili: there is no way of understanding this fact, observed in such large & distant countries, excepting by subsequent alteration from atmospheric causes. So general why not chalk all these constr. dry Dr Paris (Trans: Geolog: Soc: Cornwall) is stated said by Dr Fitton "to ascribe this concretion (of a calcareous sand) not to the agency of the sea, nor to an excess of Carbonic acid, but to the solution of Carbonate of Lime itself in water & subsequent percolation through calcareous sand; the great hardness of the stone arising from the very sparing solubility of this Carbonate, & the consequently very gradual foundation of the deposit."1 Explain surface cooled by [illeg] In my case the slow percolation takes place in a friable calcareous matter instead of in sand: hence the result of a solid limestone instead of a calcareous sandstone. — In the above described varieties of rock, over the whole summit of the promontory, vast numbers of Bulimi are imbedded.

1 This quote is from Fitton, William Henry. 1827. An account of some geological specimens, collected by Captain P.P. King, in his survey of the coasts of Australia, and by Robert Brown, Esq., on the shores of the Gulf of Carpentaria, during the voyage of Captain Flinders. Appendix C (pp. 566-605) in King, Phillip P., Narrative of a survey of the intertropical and western coasts of Australia, performed between the tears 1818 and 1822. London: John Murray, vol. 2, p. 596. The reference is to a paper by John Ayrton Paris. 1818. On a recent formation of sandstone, occurring in various parts of the northern coast of Cornwall. Transactions of the Royal Geological Society of Cornwall 1: 1-19. (Rookmaaker)

So general why not chalk all these constr. dry] added pencil.

Explain surface cooled by

871

8

K: George's Sound

The shells are [fiom] in texture, but bleached white 3538; they are of the same species, as recent ones living in the same locality. With the Bulimi Capt. Fitz Roy discovered a species of Helix 3549 & the case of an Oniscus. There was no trace of the remains of any marine animals. At one spot I obtained a section of about 15 ft perpendicular; the strata were inclined at about an angle of 12˚. — In the whole thickness the land shells are common. The lowest bed was a yellow slightly agglutinated calcareous sand 3538, in which especially a vast number of Bulimi, were enveloped. This was traversed by a broad plate (or fissure filled up) of calcareous matter, its nature intermediate betweenbetween the more friable & the compact kinds 3534: above this came was placed some of the white calcareous stone, its upper layer being converted into the compact stalactiform substance: on this, but not over a greater space, than 20 ft, there was blended a layer, a few inches thick, of a breccia, of which the fragments & matrix were composed of the same stalactiform Limestone. Again we had calcareous Sandstone, the friable calcareous white matter, with some

came was placed] added pencil.

872

9

K: George's Sound

shells firmly imbedded in it, & as before capped with the hard solid layer. Any person, who should examine the compact nature of these rocks, their alternate & nearly distinct strata, would feel convinced that they had been deposited in the ordinary subaqueous manner. But taking into consideration the necessary circumstances connected with their present position & origin, & their imbedded organic remains, a different opinion would will probably be formed. — We must imagine, that at a former period, where the land stood at a lower level, that ferruginous & calcareous matter & minute particles of quartz, was spread abroad over the bottom of the sea. These substances smoothed over the general level of the country & encased the submarine hills & ridges of Granite. At such points, during the earlier stages of the general elevation, we must believe, that small Is.ds would be formed composed solely of the calcareous rocks & Sandstones. Eventually, these Islands, by such exertions of the subterranean forces, might be

873

10

K: George's Sound

converted into promontories & parts of the mainland. Bearing in mind that Bald Head, as now situated, by a depression of the land, would form an Island; (larger, but similar in nature to Michaelmus Isd. which, according to Flinders is Granite capped with the calcareous layers) there can be no doubt that the progressive changes pointed out, did originally there take place. — The question then immediately arises, how happened it, that the first elevated strata, lying on the little Island & situated in the open sea should contain hundreds of thousands of land shells & not one marine one. shell. — The difficulty, supposing the formation to be submarine, appears to me invincible: it is likewise futile to say that strata were deposited in a lake, for on that supposition the whole surface of the little Isd. must have been covered with a pool of fresh water, divided by an invisible barrier from the ocean. Now let us imagine, what the simple fact of the enormous quantity of land shells seems to point out, namely that on a small Island, composed of calcareous

874

11

K: George's Sound

Sandstone & exposed to a violent surf, that soon sand dunes had accumulated; & that amongst them the Bulimi lived, died & were imbedded. I may mention, that I observed in Patagonia & the arid Traversias in Northern Chili, that a calcareous, rocky, & extremely dry soil, was favourable to an extraordinary degree, to the production of land shells. — In the fifteen feet section mentioned above, we must believe that the winds, after having accumulated the lower inclined strata, & the rain having converted the superficial layer, into a hard limestone, again carried, in the manner that daily may be seen on any sandy coast, a fresh mass of calcareous sand, the upper layer of which again undergoing the same change. The partial layer of brecciated rock may easily be accounted for, by a part of a sand dune, having subsided (from heavy rains, or other causes) during the progress of superficial consolidation. In support of this view, I must mention

875

12

K. George's Sound

a not unfrequent appearance of the softer Sandstone strata, namely that peculiar, lined surface, which may always be seen in sand drifted by the wind over minute inequalities, such as bits of sticks or stones, or over a large surface. — To call solid strata, subaerial formations, may, at first appear bold & startling; but such, I cannot doubt, is the correct view of their origin. — I was at this time not [illeg] Having arrived at the foregoing conclusion, I will now describe, those peculiar calcareous cylindrical projections, which originally were mistaken for coral, still remaining in the position in which it grew. These bodies occur all over the promontory of Bald head; they are found in the greatest profusion in the same strata with the shells Bulimi & to the same depth. I will only attempt to describe their figure & appearance; by stating that on Capt. FitzRoy, pointing out certain ones lying on the ground, I was quite unable, before touching them, to say, whether they were actual roots of bushes, or broken parts of their branches, or calcareous models imitating such forms. Their general diameter is from

I was at this time not [illeg]] added pencil.

876

13

K. George's Sound

that of a finger to the wrist, some few considerably larger, & very many much smaller, than these dimensions. — The most common position is vertical; many however are inclined & some horizontal; the greater number, branch downwards, like roots. — I saw, on the side of a little cliff, one very tortuous one, which extended in a perpendicular direction upwards of 3 ft in the ground; others again were suddenly bent into a horizontal line, like after the manner of a root, when it meets with an obstacle to its course. mineralogical nature ∴ project In one great bare spot, where the decomposed sandstone, had been removed by the wind, these bodies, generally of small diameter, projected upward to the height of a foot. They were so close together, that in walking, it was impossible to avoid cracking & breaking many at each step. The resemblance in parts, to the roots, of bushes growing in sand dunes, which had been exposed by the removal of the sand; & in other parts, to a shrubbery nearly burnt to the ground, was more strikingly exact, than any description will render intelligible.

mineralogical nature ∴ project] added pencil.

877

14

King George's Sound

These cylindrical models are generally composed of either the white friable calcareous rock, or the stalactiform kind 3539 ... 3547; this latter frequently only forms the axis; sometimes the axis is of the friable sort & the outer parts sandstone. Land shells are not unfrequently attached to the outer coating. — In very many the central axis, even when most compact, is penetrated by hair-formed or linear cavities, & these are partially filled up with much a lot decomposed woody fibres. (My specimens (excepting partially 3547) unfortunately do not show this fact well). Independent of all these facts, the mere evidence of external form, would have convinced me that the calcareous matter has filled up, the cavity left by the a decayed root or branch. In a time petrifaction, every particle of organic matter is separately replaced by one of stone; but in this case the whole, or nearly such, has been removed before the stony matter was washed in by the action of the rains. It will be observed, that this view strictly agrees with the idea of the strata, being the consolidated matter of sand dunes. —

a lot] added pencil.

877 verso

Particles of shells
brown, purple
black in blowpipe
number of rocks counted like Ascension
[Meagry]
superior centered layer pure over silicen
surface weathered
dry climate round of changes

though stalactites, not crystal as compact as any of the oldest foundation

page written in pencil

878

15

K. George's Sound

M. Peron, from his more extended observations appears to have drawn similar conclusions. Dr Fitton, examining only the specimens, brought taken to England, by Capt. King, considered these bodies to be calcareous concretions of a stalactitic form. He compares them, to some brought from Madeira & other localities, & probably like those probably described by me in the superficial covering of Banda Oriental. — They sorting may yet perhaps be At first, when I examined the structure of the smaller, root-like bodies, I was perplexed concerning their origin; I observed that frequently, the smaller roots, which branched downwards, from different main stems, would unite & blend into plates or veins, running in various directions. The explanation of this fact is obvious; the smaller roots, from surrounding plants will always be found filling up cracks formed in any solid or resisting soil, such as the calcareous sand must have been in the earliest periods of its solidification. Subsequently, these cracks, filled with radicles, & the roots themselves, would, upon the decay of the vegetable matter, be filled with the same matter, &

probably] added pencil.

879

16

K. George's Sound

so create the deceptive appearance. As the land rose, during the periods of its elevation, sand dunes would accumulate lower & lower, as the flanks of the hills; in them bushes would grow & land shells abound. By degrees, the sand becoming solidified, the shells would be imbedded, & the bushes would perish; their decayed roots & branches would then become so many casts from to be occupied by the calcareous matter. Hence not only the summit, but the sides of the hills, for someway downwards, are encased with this formation. I do not believe, but am far from feeling sure, that this process is not going on at this present day: but as a proof that such could happen, I may mention, that the fragments of the solid state, thrown up on the sea beach by the heavier gales are cemented into a firm Breccia. As an objection to the opinion, which I have formed of the origin of the calcareous strata, it may be asked, where will a sea coast be found, near which pure calcareous powder is drifted about, in a like manner as sand in ordinary sand dunes? (a) I can give no answer to this; excepting that

879 verso

(a) April 1835
the sand on the shore of the Lagoon Isd of Keeling, is entirely calcareous. — I could not discover in the sand, a particle otherwise constituted. But there was this difference that all the Particles had served at one time to form parts of living animals, whereas here the matter must have been a calcareous powder like at St Jago

880

17

K. George's Sound

it would appear probable, that in such cases, as where the calcareous stratum at St Jago (C. de Verd's) was deposited, that the beach was was also purely calcareous. — Respecting the origin of so much calcareous matter, M. Peron attributes it to the presence of comminuted shells. Of such fragments, I could perceive, at this place, no vestiges: indeed it appears to me, only removing the difficulty one step further back. I incline to go directly to a period of volcanic agency in this SW extremity of Australia; this such a period is perhaps also pointed by the numbers of Trappean dikes, which traverse the Granite rocks. It will be seen in Dr Fittons appendix, that the formation, to which the strata of K. George's Sound belong, to is an immensely extended one: It covers on the West coast, a space of 25 degrees in Latitude & the same in Longitude, & is even found in the gulf of Carpentaria. From imbedded shells, examined by the French naturalists, it appears certain, that the formation & the rise of the land, all belong to a very recent date. The calcareous parts, as has

881

18

King. George's Sound

already been mentioned, strictly resembles, a similar great formation in S. America; it will hence be seen, that such rocks, although not very abundant in Europe, in the geology of Globe, hold a conspicuous place. I have described in detail all the circumstances at Bald Head, both from the interest attached to any disputed point, but chiefly because the existence of alternating strata of solid rock, formed out of water, was to me a novel & interesting fact. —

881 verso

Peron gives exactly same account as mine of Petrified trees, but not so strictly geological. — He never visited Bald Head & ∴ think it different from rest of coast. — Incrustation over 25˚ of Lat & about same of Longitude. S & W: & NW of North of New Holland

Vol II p 168, account of incrustation in detail

Maccullock on Arenaceous-calcareous strata Royal Institut: Vol XVI. p 79

R.N. p. 12

Daubusson on angular concretions in Limestone, Vol II p 345 347

On recent formations of [Hydrate] of iron p. 454, & 476


This document has been accessed 4927 times

Return to homepage

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

File last updated 2 July, 2012