Coral Reefs · Charles Darwin
APPENDIX.
_Beveridge Reef_, 20° S., 167° W., is described in the “Naut. Mag.” (May 1833, page 442) as ten miles long in a N. and S. line, and eight wide; “in the inside of the reef there appears deep water;” there is a passage near the S.W. corner: this therefore seems to be a submerged atoll, and is coloured blue. _Savage_ Island, 19° S., 170° W., has been described by Cook and Forster. The younger Forster (volume ii., page 163) says it is about forty feet high: he suspects that it contains a low plain, which formerly was the lagoon. The Rev. J. Williams informs me that the reef fringing its shores, resembles that round Mangaia; coloured red. FRIENDLY ARCHIPELAGO. _Pylstaart_ Island. Judging from the chart in Freycinet’s “Atlas,” I should have supposed that it had been regularly fringed; but as nothing is said in the “Hydrog. Memoir” (or in the “Voyage” of Tasman, the discoverer) about coral-reefs, I have left it uncoloured.—_Tongatabou:_ In the “Atlas of the Voyage of the ‘Astrolabe’,” the whole south side of the island is represented as narrowly fringed by the same reef which forms an extensive platform on the northern side. The origin of this latter reef, which might have been mistaken for a barrier-reef, has already been attempted to be explained, when giving the proofs of the recent elevation of this island.— In Cook’s charts the little outlying island also of _Eoaigee_, is represented as fringed; coloured red.—_Eoua_. I cannot make out from Captain Cook’s charts and descriptions, that this island has any reef, although the bottom of the neighbouring sea seems to be corally, and the island itself is formed of coral-rock. Forster, however, distinctly (“Observations,” page 14) classes it with high islands having reefs, but it certainly is not encircled by a barrier-reef and the younger Forster (“Voyage,” volume i., page 426) says, that “a bed of coral-rocks surrounded the coast towards the landing-place.” I have therefore classed it with the fringed islands and coloured it red.
The several islands lying N.W. of Tongatabou, namely _Anamouka_, _Komango_, _Kotou_, _Lefouga_, _Foa_, &c., are seen in Captain Cook’s chart to be fringed by reefs, in several of them are connected together. From the various statements in the first volume of Cook’s “Third Voyage,” and especially in the fourth and sixth chapters, it appears that these reefs are of coral-formation, and certainly do not belong to the barrier class; coloured red.—_Toufoua_ & _Kao_, forming the western part of the group, according to Forster have no reefs; the former is an active volcano.—_Vavao_. There is a chart of this singularly formed island, by Espinoza: according to Mr. Williams it consists of coral-rock: the Chevalier Dillon informs me that it is not fringed; not coloured. Nor are the islands of _Latte_ and _Amargura_, for I have not seen plans on a large scale of them, and do not know whether they are fringed. _Niouha_, 16° S., 174° W., or _Keppel_ Island of Wallis, or _Cocos_ Island. From a view and chart of this island given in Wallis’s “Voyage” (4to edition) it is evidently encircled by a reef; coloured blue: it is however remarkable that _Boscawen_ Island, immediately adjoining, has no reef of any kind; uncoloured. _Wallis Island_, 13° S., 176° W., a chart and view of this island in Wallis’s “Voyage” (4to edition) shows that it is encircled. A view of it in the “Naut. Mag.” July 1833, page 376, shows the same fact; blue.
_Alloufatou_, or _Horn_ Island, _Onouafu_, or _Proby_ Island, and _Hunter_ Islands, lie between the Navigator and Fidji groups. I can find no distinct accounts of them. FIDJI or VITI GROUP.—The best chart of the numerous islands of this group, will be found in the “Atlas of the ‘Astrolabe’s’ Voyage.” From this, and from the description given in the “Hydrog. Memoir,” accompanying it, it appears that many of these islands are bold and mountainous, rising to the height of between 3,000 and 4,000 feet. Most of the islands are surrounded by reefs, lying far from the land, and outside of which the ocean appears very deep. The “Astrolabe” sounded with ninety fathoms in several places about a mile from the reefs, and found no bottom. Although the depth within the reef is not laid down, it is evident from several expressions, that Captain D’Urville believes that ships could anchor within, if passages existed through the outer barriers. The Chevallier Dillon informs me that this is the case: hence I have coloured this group blue. In the S.E. part lies _Batoa_, or _Turtle_ Island of Cook (“Second Voyage,” volume ii., page 23, and chart, 4to edition) surrounded by a coral-reef, “which in some places extends two miles from the shore;” within the reef the water appears to be deep, and outside it is unfathomable; coloured pale blue. At the distance of a few miles, Captain Cook (Ibid., page 24) found a circular coral-reef, four or five leagues in circuit, with deep water within; “in short, the bank wants only a few little islets to make it exactly like one of the half-drowned isles so often mentioned,”—namely, atolls. South of Batoa, lies the high island of _Ono_, which appears in Bellinghausen’s “Atlas” to be encircled; as do some other small islands to the south; coloured pale blue; near Ono, there is an annular reef, quite similar to the one just described in the words of Captain Cook; coloured dark blue.
_Rotoumah_, 13° S., 179° E.—From the chart in Duperrey’s “Atlas,” I thought this island was encircled, and had coloured it blue, but the Chevallier Dillon assures me that the reef is only a shore or fringing one; red. _Independence_ Island, 10° S., 179° E., is described by Mr. G. Bennett, (“United Service Journal,” 1831, part ii., page 197) as a low island of coral-formation, it is small, and does not appear to contain a lagoon, although an opening through the reef is referred to. A lagoon probably once existed, and has since been filled up; left uncoloured. ELLICE GROUP.—_Oscar_, _Peyster_, and _Ellice_ Islands are figured in Arrowsmith’s “Chart of the Pacific” (corrected to 1832) as atolls, and are said to be very low; blue.—_Nederlandisch_ Island. I am greatly indebted to the kindness of Admiral Krusenstern, for sending me the original documents concerning this island. From the plans given by Captains Eeg and Khremtshenko, and from the detailed account given by the former, it appears that it is a narrow coral-island, about two miles long, containing a small lagoon. The sea is very deep close to the shore, which is fronted by sharp coral-rocks. Captain Eeg compares the lagoon with that of other coral-islands; and he distinctly says, the land is “very low.” I have therefore coloured it blue. Admiral Krusenstern (“Memoir on the Pacific,” Append., 1835) states that its shores are eighty feet high; this probably arose from the height of the cocoa-nut trees, with which it is covered, being mistaken for land. —_Gran Cocal_ is said in Krusenstern’s “Memoir,” to be low, and to be surrounded by a reef; it is small, and therefore probably once contained a lagoon; uncoloured.—_St. Augustin_. From a chart and view of it, given in the “Atlas of the ‘Coquille’s’ Voyage,” it appears to be a small atoll, with its lagoon partly filled up; coloured blue.
GILBERT GROUP.—The chart of this group, given in the “Atlas of the ‘Coquille’s’ Voyage,” at once shows that it is composed of ten well characterised atolls. In D’Urville and Lottin’s chart, _Sydenham_ is written with a capital letter, signifying that it is high; but this certainly is not the case, for it is a perfectly characterised atoll, and a sketch, showing how low it is, is given in the “‘Coquille’s’ Atlas.” Some narrow strip-like reefs project from the southern side of _Drummond_ atoll, and render it irregular. The southern island of the group is called _Chase_ (in some charts, _Rotches_); of this I can find no account, but Mr. F.D. Bennett discovered (“Geographical Journal”, volume vii., page 229), a low extensive island in nearly the same latitude, about three degrees westward of the longitude assigned to Rotches, but very probably it is the same island. Mr. Bennett informs me that the man at the masthead reported an appearance of lagoon-water in the centre; and, therefore, considering its position, I have coloured it blue. —_Pitt_ Island, at the extreme northern point of the group, is left uncoloured, as its exact position and nature is not known.—_Byron_ Island, which lies a little to the eastward, does not appear to have been visited since Commodore Byron’s voyage, and it was then seen only from a distance of eighteen miles; it is said to be low; uncoloured.
_Ocean_, _Pleasant_, and _Atlantic_ Islands all lie considerably to the west of the Gilbert group: I have been unable to find any distinct account of them. Ocean Island is written with small letters in the French chart, but in Krusenstern’s “Memoir” it is said to be high. MARSHALL GROUP.—We are well acquainted with this group from the excellent charts of the separate islands, made during the two voyages of Kotzebue: a reduced one of the whole group may be easily seen in Krusenstern’s “Atlas,” and in Kotzebue’s “Second Voyage.” The group consists (with the exception of two _little_ islands which probably have had their lagoon filled up) of a double row of twenty-three large and well-characterised atolls, from the examination of which Chamisso has given us his well-known account of coral-formations. I include _Gaspar-Rico_, or _Cornwallis_ Island in this group, which is described by Chamisso (Kotzebue’s “First Voyage,” volume iii., page 179) “as a low sickle-formed group, with mould only on the windward side.” Gaspard Island is considered by some geographers as a distinct island lying N.E. of the group, but it is not entered in the chart by Krusenstern; left uncoloured. In the S.W. part of this group lies _Baring_ Island, of which little is known (see Krusenstern’s “Appendix,” 1835, page 149). I have left it uncoloured; but _Boston_ Island I have coloured blue, as it is described (Ibid.) as consisting of fourteen small islands, which, no doubt, enclose a lagoon, as represented in a chart in the “‘Coquille’s’ Atlas.”—Two islands, _Aur Kawen_ and _Gaspar Rico_, are written in the French chart with capital letters; but this is an error, for from the account given by Chamisso in Kotzebue’s “First Voyage,” they are certainly low. The nature, position, and even existence, of the shoals and small islands north of the Marshall group, are doubtful.
NEW HEBRIDES.—Any chart, on even a small scale, of these islands, will show that their shores are almost without reefs, presenting a remarkable contrast with those of New Caledonia on the one hand, and the Fidji group on the other. Nevertheless, I have been assured by Mr. G. Bennett, that coral grows vigorously on their shores; as indeed, will be further shown in some of the following notices. As, therefore, these islands are not encircled, and as coral grows vigorously on their shores, we might almost conclude, without further evidence, that they were fringed, and hence I have applied the red colour with rather greater freedom than in other instances.—_Matthew’s Rock_, an active volcano, some way south of the group (of which a plan is given in the “Atlas of the ‘Astrolabe’s’ Voyage”) does not appear to have reefs of any kind about it.—_Annatom_, the southernmost of the Hebrides; from a rough woodcut given in the “United Service Journal” (1831, part iii., page 190), accompanying a paper by Mr. Bennett, it appears that the shore is fringed; coloured red.—_Tanna_.
Forster, in his “Observations” (page 22), says Tanna has on its shores coral-rock and madrepores; and the younger Forster, in his account (volume ii., page 269) speaking of the harbour says, the whole S.E. side consists of coral-reefs, which are overflowed at high-water; part of the southern shore in Cook’s chart is represented as fringed; coloured red.—_Immer_ is described (“United Service Journal,” 1831, part iii., page 192) by Mr. Bennett as being of moderate elevation, with cliffs appearing like sandstone: coral grows in patches on its shore, but I have not coloured it; and I mention these facts, because Immer might have been thought from Forster’s classification (“Observations,” page 14), to have been a low island or even an atoll.— _Erromango_ Island; Cook (“Second Voyage,” volume ii., page 45, 4to edition) speaks of rocks everywhere _lining_ the coast, and the natives offered to haul his boat over the breakers to the sandy beach: Mr. Bennett, in a letter to the Editor of the “Singapore Chron.,” alludes to the _reefs_ on its shores. It may, I think, be safely inferred from these passages that the shore is fringed in parts by coral-reefs; coloured red.—_Sandwich_ Island. The east coast is said (Cook’s “Second Voyage,” volume ii., page 41) to be low, and to be guarded by a chain of breakers.
In the accompanying chart it is seen to be fringed by a reef; coloured red.—_Mallicollo_; Forster speaks of the reef-bounded shore: the reef is about thirty yards wide, and so shallow that a boat cannot pass over it. Forster also (“Observations,” page 23) says, that the rocks of the sea-shore consist of madrepore. In the plan of Sandwich harbour, the headlands are represented as fringed; coloured red.—_Aurora_ and _Pentecost_ Islands, according to Bougainville, apparently have no reefs; nor has the large island of _S. Espiritu_, nor _Bligh_ Island or _Banks’_ Islands, which latter lie to the N.E. of the Hebrides. But in none of these cases, have I met with any detailed account of their shores, or seen plans on a large scale; and it will be evident, that a fringing-reef of only thirty or even a few hundred yards in width, is of so little importance to navigation, that it will seldom be noticed, excepting by chance; and hence I do not doubt that several of these islands, now left uncoloured, ought to be red.
SANTA-CRUZ GROUP.—_Vanikoro_ (Figure 1, Plate I.) offers a striking example of a barrier-reef: it was first described by the Chevalier Dillon, in his voyage, and was surveyed in the “Astrolabe”; coloured pale blue.—_Tikopia_ and _Fataka_ Islands appear, from the descriptions of Dillon and D’Urville, to have no reefs; _Anouda_ is a low, flat island, surrounded by cliffs (“‘Astrolabe’ Hydrog.” and Krusenstern, “Mem.” volume ii., page 432); these are uncoloured. _Toupoua_ (_Otooboa_ of Dillon) is stated by Captain Tromelin (“Annales Marit.” 1829, page 289) to be almost entirely included in a reef, lying at the distance of two miles from the shore. There is a space of three miles without any reef, which, although indented with bays, offers no anchorage from the extreme depth of the water close to the shore: Captain Dillon also speaks of the reefs fronting this island; coloured blue.— _Santa-Cruz_. I have carefully examined the works of Carteret, D’Entrecasteaux, Wilson, and Tromelin, and I cannot discover any mention of reefs on its shores; left uncoloured.—_Tinakoro_ is a constantly active volcano without reefs.—_Mendana Isles_ (mentioned by Dillon under the name of _Mammee_, etc.); said by Krusenstern to be low, and intertwined with reefs. I do not believe they include a lagoon; I have left them uncoloured.—_Duff’s_ Islands compose a small group directed in a N.W. and S.E. band; they are described by Wilson (page 296, “Miss. Voy.” 4to edition), as formed by bold-peaked land, with the islands surrounded by coral-reefs, extending about half a mile from the shore; at a distance of a mile from the reefs he found only seven fathoms. As I have no reason for supposing there is deep water within these reefs, I have coloured them red. _Kennedy_ Island, N.E. of Duff’s. I have been unable to find any account of it.
NEW CALEDONIA.—The great barrier-reefs on the shores of this island have already been described (Figure 5, Plate II.). They have been visited by Labillardière, Cook, and the northern point by D’Urville; this latter part so closely resembles an atoll that I have coloured it dark blue. The _Loyalty_ group is situated eastward of this island; from the chart and description given in the “Voyage of the ‘Astrolabe’,” they do not appear to have any reefs; north of this group, there are some extensive low reefs (called _Astrolabe_ and _Beaupré_,) which do not seem to be atoll-formed; these are left uncoloured. AUSTRALIAN BARRIER-REEF.—The limits of this great reef, which has already been described, have been coloured from the charts of Flinders and King. In the northern parts, an atoll-formed reef, lying outside the barrier, has been described by Bligh, and is coloured dark blue. In the space between Australia and New Caledonia, called by Flinders the Corallian Sea, there are numerous reefs. Of these, some are represented in Krusenstern’s “Atlas” as having an atoll-like structure; namely, _Bampton_ shoal, _Frederic_, _Vine_ or Horse-shoe, and _Alert_ reefs; these have been coloured dark blue.
LOUISIADE: the dangerous reefs which front and surround the western, southern, and northern coasts of this so-called peninsula and archipelago, seem evidently to belong to the barrier class. The land is lofty, with a low fringe on the coast; the reefs are distant, and the sea outside them profoundly deep. Nearly all that is known of this group is derived from the labours of D’Entrecasteaux and Bougainville: the latter has represented one continuous reef ninety miles long, parallel to the shore, and in places as much as ten miles from it; coloured pale blue. A little distance northward we have the _Laughlan_ Islands, the reefs round which are engraved in the “Atlas of the Voyage of the ‘Astrolabe’,” in the same manner as in the encircled islands of the Caroline Archipelago, the reef is, in parts, a mile and a half from the shore, to which it does not appear to be attached; coloured blue. At some little distance from the extremity of the Louisiade lies the _Wells_ reef, described in G. Hamilton’s “Voyage in H.M.S. ‘Pandora’” (page 100): it is said, “We found we had got embayed in a double reef, which will soon be an island.” As this statement is only intelligible on the supposition of the reef being crescent or horse-shoe formed, like so many other submerged annular reefs, I have ventured to colour it blue.
SALOMON ARCHIPELAGO: the chart in Krusenstern’s “Atlas” shows that these islands are not encircled, and as coral appears from the works of Surville, Bougainville, and Labillardière, to grow on their shores, this circumstance, as in the case of the New Hebrides, is a presumption that they are fringed. I cannot find out anything from D’Entrecasteaux’s “Voyage,” regarding the southern islands of the group, so have left them uncoloured.—_Malayta_ Island in a rough MS. chart in the Admiralty has its northern shore fringed.—_Ysabel_ Island, the N.E. part of this island, in the same chart, is also fringed: Mendana, speaking (Burney, volume i., page 280) of an islet adjoining the northern coast, says it is surrounded by reefs; the shores, also of Port Praslin appear regularly fringed.—_Choiseul_ Island. In Bougainville’s “Chart of Choiseul Bay,” parts of the shores are fringed by coral-reefs.— _Bougainville_ Island. According to D’Entrecasteaux the western shore abounds with coral-reefs, and the smaller islands are said to be attached to the larger ones by reefs; all the before-mentioned islands have been coloured red.—_Bouka_ Islands. Captain Duperrey has kindly informed me in a letter that he passed close round the northern side of this island (of which a plan is given in his “Atlas of the ‘Coquille’s’ Voyage”), and that it was “garnie d’une bande de récifs à fleur d’eau adherentes au rivage;” and he infers, from the abundance of coral on the islands north and south of Bouka, that the reef probably is of coral; coloured red.
Off the north coast of the Solomon Archipelago there are several small groups which are little known; they appear to be low, and of coral-formation; and some of them probably have an atoll-like structure; the Chevallier Dillon, however, informs me that this is not the case with the B. de _Candelaria_.—_Outong Java_, according to the Spanish navigator, Maurelle, is thus characterised; but this is the only one which I have ventured to colour blue. NEW IRELAND.—The shores of the S.W. point of this island and some adjoining islets, are fringed by reefs, as may be seen in the “Atlases of the Voyages of the ‘Coquille’ and ‘Astrolabe’.” M. Lesson observes that the reefs are open in front of each streamlet. The _Duke of York’s_ Island is also fringed; but with regard to the other parts of _New Ireland_, _New Hanover_, and the small islands lying northward, I have been unable to obtain any information. I will only add that no part of New Ireland appears to be fronted by distant reefs. I have coloured red only the above specified portions. NEW BRITAIN and the NORTHERN SHORE of NEW GUINEA.—From the charts in the “Voyage of the ‘Astrolabe’,” and from the “Hydrog. Memoir,” it appears that these coasts are entirely without reefs, as are the _Schouten Islands_, lying close to the northern shore of New Guinea. The western and south-western parts of New Guinea, will be treated of when we come to the islands of the East Indian Archipelago.
ADMIRALTY GROUP.—From the accounts by Bougainville, Maurelle, D’Entrecasteaux, and the scattered notices collected by Horsburgh, it appears, that some of the many islands composing it, are high, with a bold outline; and others are very low, small and interlaced with reefs. All the high islands appear to be fronted by distant reefs rising abruptly from the sea, and within some of which there is reason to believe that the water is deep. I have therefore little doubt they are of the barrier class.—In the southern part of the group we have _Elizabeth Island_, which is surrounded by a reef at the distance of a mile; and two miles eastward of it (Krusenstern, “Append.” 1835, page 42) there is a little island containing a lagoon.—Near here, also lies _Circular-reef_ (Horsburgh, “Direct.” volume i., page 691, 4th edition), “three or four miles in diameter having deep water inside with an opening at the N.N.W. part, and on the outside steep to.” I have from these data, coloured the group pale blue, and _circular-reef_ dark blue.—the _Anachorites_, _Echequier_, and _Hermites_, consist of innumerable low islands of coral-formation, which probably have atoll-like forms; but not being able to ascertain this, I have not coloured them, nor _Durour_ Island, which is described by Carteret as low.
The CAROLINE ARCHIPELAGO is now well-known, chiefly from the hydrographical labours of Lutké; it contains about forty groups of atolls, and three encircled islands, two of which are engraved in Figures 2 and 7, Plate I. Commencing with the eastern part; the encircling reef round _Ualen_ appears to be only about half a mile from the shore; but as the land is low and covered with mangroves (“Voyage autour du Monde,” par F. Lutké, volume i., page 339), the real margin has not probably been ascertained. The extreme depth in one of the harbours within the reef is thirty-three fathoms (see charts in “Atlas of ‘Coquille’s’ Voyage”), and outside at half a mile distant from the reef, no bottom was obtained with two hundred and fifty fathoms. The reef is surmounted by many islets, and the lagoon-like channel within is mostly shallow, and appears to have been much encroached on by the low land surrounding the central mountains; these facts show that time has allowed much detritus to accumulate; coloured pale blue.— _Pouynipète_, or _Seniavine_. In the greater part of the circumference of this island, the reef is about one mile and three quarters distant; on the north side it is five miles off the included high islets.
The reef is broken in several places; and just within it, the depth in one place is thirty fathoms, and in another, twenty-eight, beyond which, to all appearance, there was “un porte vaste et sur” (Lutké, volume ii., page 4); coloured pale blue.—_Hogoleu_ or _Roug_. This wonderful group contains at least sixty-two islands, and its reef is one hundred and thirty-five miles in circuit. Of the islands, only a few, about six or eight (see “Hydrog. Descrip.” page 428, of the “Voyage of the ‘Astrolabe’,” and the large accompanying chart taken chiefly from that given by Duperrey) are high, and the rest are all small, low, and formed on the reef. The depth of the great interior lake has not been ascertained; but Captain D’Urville appears to have entertained no doubt about the possibility of taking in a frigate. The reef lies no less than fourteen miles distant from the northern coasts of the interior high islands, seven from their western sides, and twenty from the southern; the sea is deep outside. This island is a likeness on a grand scale to the Gambier group in the Low Archipelago.
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