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[sketch of a reef and island in profile] E P D H C B A Islands L

generally much smaller More more

Beginning with the Lagoon: the shores are formed of fine Calcareous sand with a few fragments of Coral which more frequently is of the delicate branched kinds.

The shore has either an entirely uniform slope or has a small beach which latter circumstance generally occurs at points where the tide sweeps round or where to leeward. the waters of the Lagoon have some power— So gradual is the slope, that generally when wells have been dug within a hundred yards of the beach at spring tides, the fresh water rises within 18 or 12 inches of the general level: the water ebbs & flows in these wells. about 4 ft. in which thickness the whole is Calcareous sand. partly slightly consolidated agglutinated. This formation appears to extend some way inland: & walking across these strips of land. (which appear only a few hundred yards wide) first we meet on the surface branched & lighter Coral caused by such always been thrown as the beach advances, furthest back, & close to the outer beach the solid Astreas. — The level of the strip appears perfect but as the external beach is 5 or 6 feet above the wash of high water in ordinary weather & the lagoon side has its edge on a level with the high water there: there must be the rise in the island, equal to the height of the heavy weather beach. This few number of ft is of course quite imperceptible:

On the lagoon side inland in parts a beach of sand may be discovered which of course has been formed as beaches sometimes are now formed on that coast. —

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The stratification in whole mass of Lagoon rocks on the main horizontal, in detail very irregular.

Bones of collar of Huthuriae¹ ought to be found. — & adhaering oysters; in outer reefs

All Lamelliform Corals.²

Astrea does grow in the Lagoon

Young Islands. appear always to assume a convex side to seaward:

Some of the included fragments are 1-2 ft in diameter

The series of specimens is very interesting.

¹ Possibly Holuthuriae.

² written at the point of a bracket encompassing "far prevalent genus...these (3575)." on CUL-DAR41.41.

The stratification ... irregular] pencil.

Bones of collar ... oysters] pencil.

All Lamelliform ... on p.2] pencil.

[2]

on the corner of the Islands. bordering the passages between the reefs, there sometimes is a hillock, which appears composed of blown up sand.

(1) (probably frequently possibly in some cases consolidated as at K.G.s Sound).

The beach A is composed of well rounded fragments of solid Coral. — These are generally about 1 to 2 ft in diameter & rather thinner in depth: the far prevalent genus is Astrea: perhaps more than one species. (but species 3568 ... 72) is the common one. — The next kind in abundance is (3573 3574 3585) & then (3575). — all these are either in a tolerably perfect state or much petrified by Carb of Lime & fragments of this Breccia. — The smaller fragments are the same or a few branched kinds & milliporæ — This

A succession of beaches have formed all the outer parts of the strips of land: The sun & atmosphere acting on the larger blocks causes them to split & their angular fragments fill up the inequalities: the branched kinds are abundant on the surface because being lighter they are thrown further inland, as the beach progresses outwards. — This beach is thrown up by gales of wind, a heavy surf & spring tides. — Beneath this beach, there is an extent (at this particular section) of only 10 yards. (generally more?) of a breccia. the rock is very solid. white coloured & sonorous beneath the hammer: this breccia consist of Calcareous sand. cemented & the fragments blending into each other: generally it contains or

2v

NB The action of gales on the outer parts must be to grind & form Calcareous powder. —

recoil carry it to Seaward

N.B. Several Earthquakes & the Greenstone Rocks on the Northern Islands in the Breccia – it is sand

several small pebbles have been found of the same rock.

NB. Greenstone Rock brought by roots of trees

direction of longer axis? breadth of strips of land; line of Northern Isle = Has before been a lagoon. =

One single tree of a particular sort on one old Isd close to the Beach

The most surprising thing is the quantity of Lime! in the whole intertropical seas!

We know that sediment at K. Georges Sound will accumulate at ∠ (30°?). —

V. Humboldt¹ for inclination of Mountains.

The number of worms tend to destroy the Corallina living

Limestone strata, if formed as reefs ought to perforated with Cylindrical holes.

N.B. Crystal like pieces. broken spines of Echinus

¹ Humboldt 1819-1829. JvW

of] pencil.

recoil carry it to Seaward] pencil.

N.B. Several ... Echinus] pencil.

V. Humboldt for inclination of Mountains.] lightly marked out in pencil.

The number of worms tend to destroy the Corallina living] lightly marked out in pencil.

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is composed of any fragments of all sizes of the Corals. which are nearly perfectly petrified: there are large masses in which scarcely a trace of Organic structures can be discovered ∴ the rock would be described as a yellowish or white, Calcareous rock, with an almost Crystalline fracture: containing a few minute cavities. — The horizontal extent of this varies much, in thickness it can rarely exceed. 3 ft. — it is a very curious & interesting rock. — It is generally covered by near the limits at of high water. — this mass. is irregularly stratified & slopes, just perceptibly to seaward, owes its origin clearly the fragments heaped up & cemented by the action of atmosphere & tides:

Its quantity is constantly varying, as shown by the water worn state of the ledges: the tides sometimes heaviest gales heap it up & consolidated it─ & sometimes common action of tides remove it remove them: & gales tear off fragments to help to form the high beach. — To seaward of the Breccia

There is a flat. which in common language would be called absolutely level. but certainly in most places there is a trifling slope to seawards. — About 60 yards is quite smooth (These numbers are all small) especially as compared to West side, then it becomes traversed by shallow channels & holes. NB Sulivan¹ would include all this in reef. — which over a space of 30-40 yards increase in width & depth. It being low water & spring tides. & extraordinary smooth water by the aid of a leaping pole. we reached very far into the breakers. — Here we found great masses. rounded with a curvilinear outline, up to 8 ft in diameter

¹ Bartholemew James Sulivan (1810-1890), second Lieutenant on the Beagle. JvW

page is lightly crossed out in pencil.

seaward of the Breccia] pencil line separates the previous writing from the following.

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N.B. the greater less slope of bottom to windward owing to greater accumulation of Detritus: if such is the case? —

It is certain that the kind sub-branched. of which there are so many fragments: must grow at a little depth in greater quantity. — For structure of reef outside V. soundings.

N.B. the greater ... detritus] pencil.

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living Astrea. This species ([blank space]) formed the chief masses. — There was also of a yellowish green Millipora. which grows in thick vertical plates.. which intersect each other at various angles & form an exceedingly strong net work. V. note Book for species: the branched Millipora: &c &c In the interstices flourish strong branching Corals. —

The central dead parts of the masses of of the Millipora net work & the towers masses of Astrea are coated & raised by a Corallina. — The channels are coated with the same substance & have a little sand, at the bottom, to seaward. similar lumps for a distance of 10-20 yards might be seen beneath the water. beyond this for another 20 yards there was green water no wall & then came the Blue. —Where we stood. the masses of Astrea were from 4-8 ft in diameter, but irregular in figure. & the channels about 6 ft deep: The Astrea, was on its surface to a depth of 3 or 4 inches was dead. further inland a greater depth was dead. to seaward. without doubt the whole surface. was living. – It is a beautiful instance how short a time is sufficient to kill them: at this time under such favourable circumstances the dead parts were awash. The Astrea. extends laterally & must soon fill up the channels. — Specimens. ([blank space]) will show. a layer. additional on the sides as compared to the top. — The Millipora

entire page is lightly crossed out in pencil.

no wall] pencil.

Where we stood ... to the top] text lightly crossed out.

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NB. absence of Coral Isd^s in the Atlantic. — Coast of Peru. which perhaps are exceptions to the whole rest of the Intertropical world. —

NB. Absence ... of Peru] pencil.

All writing on the page lightly crossed out in pencil.

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equally requires constant immersion. — The interstices must are be soon to be filled up & form solid masses. — I was most surprised to see. the enormous quantity of matter. which the successive paper like layers of Corallina have accumulated, instantly the This substance evidently bears exposure. for some time to the air yet. which is very curious. must require a breaking sea: — instantly the surface of the Astrea dies. it is occupied by Corallina — The summit & sides of the dead Millipora. appear to offer most favourable situations to its growth. as do the sides & bottoms of the channels. This Corallina raised lumps 8 & 10 ft long about two feet above the level. the living solid Corals. — The absence of all points of resistance must allow this substance to flourish in the break of the sea There is another species of Corallina. [sketch] V. Specimen, although firm it is not hard. — (V 3580 specimen) — Further from the lowest break of the sea. the channels. becomes shallow & narrower; The Astrea, when it grows. is in the form of thin plates, with curvilinear edges — Here a great number of species of Algonium flourish & some stony branching Corals. — In one part, over the extent of a mile an enormous quantity of a Clam Holuthuriæ lived. partly sunk in the Coral. — NB. These are placed vertically might afford useful indication. — Worms were in Milliporæ. —

page except for bottom lines (from "a Clam" onwards) lightly crossed out in pencil; a pen line separates "...level. the living solid Corals. –" from the section starting "The absence of all points of resistance..." and they were marked over by different pencil deletions.

have accumulated ... Milliporae] pencil, with insertions in ink.

[5v blank]

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In this part Corallina likewise flourishes, but does not form elevated knobs. — In this part, they would remain long without water, although the same height. from being further from the break of the sea. — When dead probably the perhaps they would exfoliate & their fragments would help to fill up the smaller channels. — Perhaps Flinders Negro heads are of this formation. color pinkish, Flinders black. —

When we reach, the level floor. we find it quite smooth, & covered with very minute Fuci.—

The channels have been entirely filled up. & being long exposed no Corals lives there (I exclude a few hollows). — The whole is composed of a very hard solid rock. – which is petrified Coral & hard Calcareous sandstone (3578 & 3579) — It is manifest, that the few remaining channels between the living Coral. have gradually been filled with detritus the whole petrified & smoothed by the action of the tides. —

This flat slopes at a very trifling angle to the Breccia. — On its surface are scattered a few blocks (but not very large) 1 to 2. & sometimes 3 ft: which evidently have remained there sometime. & are waiting till an unusually heavy gale shall carry them to compose a Breccia or high beach — where a few channels yet remain, if a

oage in pencil; whole page is lightly crossed out in pencil. Insertions and underlining in pen.

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NB. Alcyonium includes Sigillina &c &c

Cocos Isd. connected with volcanic force of Sumatra. that rises, this falls.

page in pencil; writing is also crossed out lightly in pencil.

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a fragments of Astrea is cast, the into a cavity the lower parts of still living, it adheres & so fills up the Cavity. —

This section I understand, gives a good * general idea of the reef, the proportionate width constantly vary, the breakers being either much near close to Beach or four (?) times as far as I have stated — the inclination of the bottom & other local causes probably determines this. I cannot find out any certain relation to Windward or Leeward sides —This is a section of a reef forming on to land; on the reefs which connect the Islands. are very broard, are nearly low dry at dead low water. are intersected with numerous channels they are nearly level or rather slope to lagoon, cause as described at Tahiti their outer parts are as described & within these whole is not part quite so smooth as "the flat." probably because not [sketch] so high, the sand & other loose materials constantly being removed & carried into the lagoon. — From the width of this reef it is manifest, that such is the base of all the Islands. — Where a Minute Island was formed on the reef. the whole process was evident: — (Omitted, slope imperceptibly universally this structure to lagoon, resembles Tahiti. hence have no doubt description is right); there can be no doubt the Coral extends along outwards to sea, fragments broken off & falling on the sloping

page] pencil: top is lightly crossed out in pencil. insertions in ink.

This is a section of a reef forming on to land... sloping] each line is lightly crossed out in pencil.

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Section of Island

[sketch]¹ Sea 3 ft 3 or 4 fm
Soil
Loose fragments
Breccia
Sand on Lagoon side branching Coral Fragments & Sand
Corals in situ interstices filled up

[sketch]
Sand
Breccia Coral Breccia Coral &c
Fragments. sand —
Branched growing coral
1000 fathoms
line of possible degardation if upraised into dry land

The period of time between each elevation depression 2 would determine how far the slope, extends outside?

NB. If tides had been very small. when such a mass had accumulated, there would be very little Breccia & [illeg]

¹ This diagram is discussed in Stoddart, David R., 1995. Darwin and the seeing eye: iconography and meaning in the Beagle years. Earth Sciences History, v. 14, p. 3-22.

² Note this slip.

Section of Island] pencil.

diagrams and text] pencil.

The period of time ... slope extends outside] pencil.

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talus of sand would form foundation, as the rounded lumps of Astrea & network of Millipora extended to Seaward, the broad channels between constant break of the sea, would be lessened behind, the surface of the Astrea would die, laterally they would extend & fill up the channels — & Corallina would form projecting lumps — During the times as the front extended to seaward, so would the channels contract, the upper parts of Coral would all die further down, the lumps of Corallines crumble down & sl but the branching Corals may still flourish more. (There in front of this & sand would fill up all the remaining channels & the Coral be petrified — as soon as this was effected & the break of the sea still further removed. no Corallines or Corals would grow. & the weaning of the sea.) In this state if, the cross action of the tides & gales of wind in unusual direction (or other causes would should accumulate on the less exposed parts of the reef a heap of fragments there might be cemented; Then & form a barrier. Then the remaining channels & holes would be filled up with sand & fragments, be petrified & the surface worn smooth by the tides, & we should have the "solid field" — Upon the Breccia in the little Isd. loose (because dry) fragments would be thrown; which extending outwards would form the island, & on the inside would from same process the sand of lagoon.

& sand would fill up all ... weaning of the sea.)] crossed out.

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Small Pumice pebbles abundant on beach of Lagoon – from Sumatra, like the seeds

Small Pumice ... seeds] pencil.

abundant] ink.

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Wednesday [6 April 1836]

Visited the SE Isd. — By an old chart said to consist of several Isds the junctions are still visible by being narrower, lower & even the trees younger. — In a well near the houses. we found strata 3-4 ft thick either of slightly indurated not very hard Calcareous sandstone, a breccia of rounded fragments, which in one part was excessively compact. — At spring tides, the water within well rises within 2 ft. of general surface, & probably this height does not equal the rise in the lagoon. therefore the land is so much less higher than the 2 ft. —

Whole surface of Islands strewed over with the (2d common kind) & some Astrea, well rounded. & some shells which Mr Lesk¹ says only are found outside — the cause must lie in these being always tossed farthest as the coast travels seaward This quite agrees with reef being covered from seaward. = On the sea-beach, the reef from Breakers to coast about 200 yd.; of this the structure is identical with what has been described. excepting that the Breccia was in larger proportion. — The beach was here about 9 ft above spring tides. & therefore the land at this spot & there are hillocks of blown up sand about 14 ft: It is close to the beach where this 9 ft is found: which must make the land 8 ft higher than at the wells. — Making allowances – for the wear & tear splitting & settling of the fragments. & some of the sand being blown away. Yet, the 9 ft land would probably. always remain higher than that near the lagoon, which has been accumulated in a similar manner. This may be owing possibly to the inclination of the land, at an earlier period, causing the sea to break further off than at present, & so to heap the fragments less high. — If however, this outward increased

¹ William C. Liesk (sometimes spelled Leisk), an English resident on Keeling. See Armstrong 1991. JvW

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X. Considering the breadth of reef between the 2 this must always happen. —

As the reef is broarder at SE. point, than behind Houses = How are the soundings. =

NB. Yet Sulivan makes the reef. very narrow. on some of the point on SE part (owing to greater accumulation?)

The four Bulwark agents

1 Astrea
2 [sketch]¹ }
3 Millepora } ? which most effective
4 Corallina

The width of B discoloured water beyond the Breakers varys much. — I could discover no law. – V. chart excepting on West Isd. where the narrower the reef. the wider the pale water & V. & Versâ. Sulivan.

¹ Little diagram, as on p. 5, of unnamed species of "corallina".

X. Considering ... always happen. —] pencil.

As the reef ... soundings. =] pencil.

The four Bulwark agents ... Corallina] pencil.

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height was general – I should suspect. that at the violent Earthquakes, the land may subside a trifle, as it rises at Chiloe, without being noticed; the outer parts near the Beach would constantly be repaired, but not so the interior. —

The upper parts of the Lagoon are much filled up with Coral. extensive flats are nearly awash at low water, & only here & there a circular hole of 10 or 12 fathoms deep is left, & these are daily being filled up. The more common depth is about 6 fathoms, so that this is a shallow lagoon. & here perhaps we may infer that all subsiding movements on any great scale here has long been quiet.

The commonest species are the (Seriatopora. .. Crown Coral, (a yellow sort [blank]), ([blank]) Fungia. Escara Chama:– Meandrina in great loose balls. — Astrea, (the bulwark species) infrequent. as are the two other kinds which are found outside & Corallina not abundant. – These Corals are brittle & soft, & on standing on them a person breaks through them to some depth. —

For a space of some miles, near the head of Bay, there are extensive flats of dead Corals, such as are found a mile further down alive, these are remain in their proper position, but are quite rotten & old, so that a person sinks as in walking through straw. — I was much puzzled. what could have killed them, without a general change of level. — I look at the cause. as owing to the strong wind causing very low tides, which before the SE Island was united would not happen, but rather. as happens.

& Corallina not abundant] pencil.

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All the Sand is purely Calcareous

All the Sand ... Calcareous] pencil.

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in the Pacifick, a strong breeze would pump in quantities of water. — From this change of circumstances. the part which might be exposed for an hour to the sun, might well be 2 — or even 3 ft lower than formerly & this would quite suffice to kill a Coral flat, which had attained its extreme height. —

I observed this dead brittle Coral, showed no signs of adhering & forming as rocks. but rather of wasting —

The shores at the head of the lagoon, have a different character from any other part; here is an extensive bed of mud which reaches far into the bay, at a very small angle. — Here flourishes the Turtle grass – This mud is entirely Calcareous. — I can only account for its presence by the trade wind drifting across the finer particles of sand which is accumulating on the Weather coast.

If we imagine the future state of the Lagoon. we shall see a perfect ring of land formed. & with. new tidal opening complete excepting by one orifice. — The Corals will have grown up over whole extent. to their highest limits that is to lowest low water & will exist in the state, in which they occur at head of bay. that; their comminuted fragments will form a fine bed, on which Turtle grass will grow. — Which will be left nearly dry at low water. — hence the opening will be merely tidal. — This is the present state of Keeling Isds —

If we except the fine sand, which (where many trees were not present) might be drifted from the one or windward side. It is difficult to imagine how it would

[11v]

Cocoa nut trees & old store encroached on by the lagoon.

There are on Water Isd. several. stores & other buildings. built. 6- to 8 years ago. which were built on the beach. above above common highest water mark: now these are surrounded by water, during every tide: fact agrees with cocoa nut trees

Well in nearer to the lagoon. than outside centre of Isd. sand to high water mark. beneath which loose (outer — fragments well rounded [ )?   ]

therefore here there must have been considerable increase from Lagoon side +++

Depression corresponds to Sumatra line of Elevation as Pacifick to Cordilleras.

+++. It is remarkable. that at high water mark in the well (therefore certainly a little below same in Lagoon) that there should be loose small pebbles from outside (NB since seeing spit in leeward part of lagoon. I can distinguish the two): at same height outside. there would be Breccia or base of high beach of large fragments. This explicable from extreme width of reef. before land: but it is one out of many arguments helped by small depression.=

Cocoa nut trees & old store encroached on by the lagoon.] pencil overwritten in ink.

Well in] pencil.

entre of Isd. sand ... rounded] pencil.

Depression corresponds ... Cordilleras.] pencil.

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& in proportion as Lagoon nearly filled up, fresh water & impurities would be more ingenious

ever entirely be silted up. — We must not allow false appearances to misguide & to compare a lagoon with a lake surrounded by higher land. from which detritus might be carried. — These facts may account for infrequency of Lagoons, being converted into absolutely dry land ++ — moreover. when the lagoon was nearly filled up the impurity of the water might add. much to the slow growth of the Corals —

++ Independent of repeated depressions. —

[small diagram of two reef lines] 1 2

These two kinds of reef are equally common: even perhaps. (2) is most common:

These two kinds. although at first appearing. very different. then are the same: the lumps & long continued smooth breakwater very curious are raised about 2 ft above the level of the flat: they are each composed of superficial Corallina. — We might suppose in number one. if the lateral & outward growth of was checked: the Astreas &c would close up the channels & the Corallina knobs unite into a breakwater. Perhaps. the species may [be] slightly different in the two cases?? not essentially: yet in the one case Petrifaction appears to take place & not in the other. — I could pick the knobs. but not the Breakwater. —

It is hard to believe that the solid breakwater is cut down. as the breakers recede outwards. yet such almost must be the case: as soon as the Corallina dies, wear & tear commences. & we know in solid rock. the upper part of tidal surface. suffers most degradation. — If the breakwater is not cut smooth the reef cannot increase laterally for if so such mounds would appear on the flat. —

& in proportion as Lagoon ... repeated depressions. —] pencil.

[12v]

The Windward side with respect to land thought oldest. most perfect

Mem. Keeling Isd. opens to windward

Mr. Sulivan states that the SE decidedly in the windward side & SW leeward — Curious facts of blocks thrown up, – doubtless when on outlying Islet; sand dunes protected by Vegetation: no ridge on strips of land; ∴ not essential to a perfect lagoon Isd.– no ledges in lagoon: —

I believe the stone crops out in several places on sides of Lagoon, which looks like a trifling subsidence —

[7-11 April 1836] Horsburgh Isd. on the Lagoon side in one spot has accidentally fine calcareous sand is turned into hard rock is stratified [small sketch] (a) (a) i.e., much smaller are like Coquimbo — it must be the lower part of sand, hardened intermed[obscured] beds happening to be softer. — The Island. being to leeward appears to have increased largely on lagoon side by sand heaped up hence low. levels — In the Breccia outside. rounded pieces of Breccia again become cemented. — Certainly the lowest parts of the coarse beach: = (NB a note has been entered in Coquimbo paper)

The Breccia. beach being much nearer to Breakers than on Leeward may be owing to surf — & not to comparative growth of Corals — The strips of land. may be owing to increase from Lagoon side. — It is hard to judge from their compounded causes

The Windward side] pencil.

thought oldest. most perfect] pencil.

M^r. Sulivan states ... strips of land;] pencil.

no ledges in lagoon: —] pencil.

I believe ... subsidence — ] pencil.

Horsburgh Is^d. on ... increase from Lagoon side] pencil.