Coral Reefs

SOLOMON 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 Labillardiere, 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 recifs a 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 Lutke; 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. Lutke, 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. – POUYNIPETE, 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" (Lutke, 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. Of the groups of low (In D'Urville and Lottin's chart, Peserare is written with capital letters; but this evidently is an error, for it is one of the low islets on the reef of Namonouyto (see Lutke's charts) – a regular atoll.) islands forming the chief part of the Caroline Archipelago, all those of larger size, have the true atoll-structure (as may be seen in the "Atlas" by Captain Lutke), and some even of the very small ones, as MACASKILL and DUPERREY, of which plans are given in the "Atlas of the 'Coquille's' Voyage." There are, however, some low small islands of coral-formation, namely OLLAP, TAMATAM, BIGALI, SATAHOUAL, which do not contain lagoons; but it is probable that lagoons originally existed, but have since filled up: Lutke (volume ii., page 304) seems to have thought that all the low islands, with only one exception, contained lagoons. From the sketches, and from the manner in which the margins of these islands are engraved in the "Atlas of the Voyage of the 'Coquille'," it might have been thought that they were not low; but by a comparison with the remarks of Lutke (volume ii., page 107, regarding Bigali) and of Freycinet ("Hydrog. Memoir 'L'Uranie' Voyage," page 188, regarding Tamatam, Ollap, etc.), it will be seen that the artist must have represented the land incorrectly. The most southern island in the group, namely PIGUIRAM, is not coloured, because I have found no account of it. NOUGOUOR, or MONTE VERDISON, which was not visited by Lutke, is described and figured by Mr. Bennett ("United Service Journal," January 1832) as an atoll. All the above-mentioned islands have been coloured blue.

WESTERN PART OF THE CAROLINE ARCHIPELAGO.

FAIS Island is ninety feet high, and is surrounded, as I have been informed by Admiral Lutke, by a narrow reef of living coral, of which the broadest part, as represented in the charts, is only 150 yards; coloured red. – PHILIP Island., I believe, is low; but Hunter, in his "Historical Journal," gives no clear account of it; uncoloured. – ELIVI; from the manner in which the islets on the reefs are engraved, in the "Atlas of the 'Astrolabe's' Voyage," I should have thought they were above the ordinary height, but Admiral Lutke assures me this is not the case: they form a regular atoll; coloured blue. – GOUAP (EAP of Chamisso), is a high island with a reef (see chart in "Voyage of the 'Astrolabe'"), more than a mile distant in most parts from the shore, and two miles in one part. Captain D'Urville thinks that there would be anchorage ("Hydrog. Descript. 'Astrolabe' Voyage," page 436) for ships within the reef, if a passage could be found; coloured pale blue. – GOULOU, from the chart in the "'Astrolabe's' Atlas," appears to be an atoll. D'Urville ("Hydrog. Descript." page 437) speaks of the low islets on the reef; coloured dark blue.

PELEW ISLANDS.

Krusenstern speaks of some of the islands being mountainous; the reefs are distant from the shore, and there are spaces within them, and not opposite valleys, with from ten to fifteen fathoms. According to a MS. chart of the group by Lieutenant Elmer in the Admiralty, there is a large space within the reef with deepish water; although the high land does not hold a central position with respect to the reefs, as is generally the case, I have little doubt that the reefs of the Pelew Islands ought to be ranked with the barrier class, and I have coloured them pale blue. In Lieutenant Elmer's chart there is a horseshoe-formed shoal, laid down thirteen miles N.W. of Pelew, with fifteen fathoms within the reef, and some dry banks on it; coloured dark blue. – SPANISH, MARTIRES, SANSEROT, PULO ANNA and MARIERE Islands are not coloured, because I know nothing about them, excepting that according to Krusenstern, the second, third, and fourth mentioned, are low, placed on coral-reefs, and therefore, perhaps, contain lagoons; but Pulo Mariere is a little higher.

MARIANA ARCHIPELAGO, or LADRONES.

GUAHAN. Almost the whole of this island is fringed by reefs, which extend in most parts about a third of a mile from the land. Even where the reefs are most extensive, the water within them is shallow. In several parts there is a navigable channel for boats and canoes within the reefs. In Freycinet's "Hydrog. Mem." there is an account of these reefs, and in the "Atlas," a map on a large scale; coloured red. – ROTA. "L'ile est presque entierement entouree des recifs" (page 212, Freycinet's "Hydrog. Mem."). These reefs project about a quarter of a mile from the shore; coloured red. – TINIAN. THE EASTERN coast is precipitous, and is without reefs; but the western side is fringed like the last island; coloured red. – SAYPAN. The N.E. coast, and likewise the western shores appear to be fringed; but there is a great, irregular, horn-like reef projecting far from this side; coloured red. – FARALLON DE MEDINILLA, appears so regularly and closely fringed in Freycinet's charts, that I have ventured to colour it red, although nothing is said about reefs in the "Hydrographical Memoir." The several islands which form the northern part of the group are volcanic (with the exception perhaps of Torres, which resembles in form the madreporitic island of Medinilla), and appear to be without reefs. – MANGS, however, is described (by Freycinet, page 219, "Hydrog.") from some Spanish charts, as formed of small islands placed "au milieu des nombreux recifs;" and as these reefs in the general chart of the group do not project so much as a mile; and as there is no appearance from a double line, of the existence of deep water within, I have ventured, although with much hesitation, to colour them red. Respecting FOLGER and MARSHALL Islands which lie some way east of the Marianas, I can find out nothing, excepting that they are probably low. Krusenstern says this of Marshall Island; and Folger Island is written with small letters in D'Urville's chart; uncoloured.

BONIN OR ARZOBISPO GROUP.

PEEL Island has been examined by Captain Beechey, to whose kindness I am much indebted for giving me information regarding it: "At Port Lloyd there is a great deal of coral; and the inner harbour is entirely formed by coral-reefs, which extend outside the port along the coast." Captain Beechey, in another part of his letter to me, alludes to the reefs fringing the island in all directions; but at the same time it must be observed that the surf washes the volcanic rocks of the coast in the greater part of its circumference. I do not know whether the other islands of the Archipelago are fringed; I have coloured Peel Island red. – GRAMPUS Island to the eastward, does not appear (Meare's "Voyage," page 95) to have any reefs, nor does ROSARIO Island (from Lutke's chart), which lies to the westward. Respecting the few other islands in this part of the sea, namely the SULPHUR Islands, with an active volcano, and those lying between Bonin and Japan (which are situated near the extreme limit in latitude, at which reefs are formed), I have not been able to find any clear account.

WEST END OF NEW GUINEA.

PORT DORY. From the charts in the "Voyage of the 'Coquille'," it would appear that the coast in this part is fringed by coral-reefs; M. Lesson, however, remarks that the coral is sickly; coloured red. – WAIGIOU. A considerable portion of the northern shores of these islands is seen in the charts (on a large scale) in Freycinet's "Atlas" to be fringed by coral-reefs. Forrest (page 21, "Voyage to New Guinea") alludes to the coral-reefs lining the heads of Piapis Bay; and Horsburgh (volume ii., page 599, 4th edition), speaking of the islands in Dampier Strait, says "sharp coral-rocks line their shores;" coloured red. – In the sea north of these islands, we have GUEDES (or FREEWILL, or ST. DAVID'S), which from the chart given in the 4to edition of Carteret's "Voyage," must be an atoll. Krusenstern says the islets are very low; coloured blue. – CARTERET'S SHOALS, in 2 deg 53' N., are described as circular, with stony points showing all round, with deeper water in the middle; coloured blue. – AIOU; the plan of this group, given in the "Atlas of the Voyage of the 'Astrolabe'," shows that it is an atoll; and, from a chart in Forrest's "Voyage," it appears that there is twelve fathoms within the circular reef; coloured blue. – The S.W. coast of New Guinea appears to be low, muddy, and devoid of reefs. The ARRU, TIMOR-LAUT, and TENIMBER groups have lately been examined by Captain Kolff, the MS. translation of which, by Mr. W. Earl, I have been permitted to read, through the kindness of Captain Washington, R.N. These islands are mostly rather low, and are surrounded by distant reefs (the Ki Islands, however, are lofty, and, from Mr. Stanley's survey, appear without reefs); the sea in some parts is shallow, in others profoundly deep (as near Larrat). From the imperfection of the published charts, I have been unable to decide to which class these reefs belong. From the distance to which they extend from the land, where the sea is very deep, I am strongly inclined to believe they ought to come within the barrier class, and be coloured blue; but I have been forced to leave them uncoloured. – The last-mentioned groups are connected with the east end of Ceram by a chain of small islands, of which the small groups of CERAM-LAUT, GORAM and KEFFING are surrounded by very extensive reefs, projecting into deep water, which, as in the last case, I strongly suspect belong to the barrier class; but I have not coloured them. From the south side of Keffing, the reefs project five miles (Windsor Earl's "Sailing Direct. for the Arafura Sea," page 9).

CERAM.

In various charts which I have examined, several parts of the coast are represented as fringed by reefs. – MANIPA Island, between Ceram and Bourou, in an old MS. chart in the Admiralty, is fringed by a very irregular reef, partly dry at low water, which I do not doubt is of coral-formation; both islands coloured red. – BOUROU; parts of this island appear fringed by coral-reefs, namely, the eastern coast, as seen in Freycinet's chart; and CAJELI BAY, which is said by Horsburgh (volume ii., page 630) to be lined by coral-reefs, that stretch out a little way, and have only a few feet water on them. In several charts, portions of the islands forming the AMBOINA GROUP are fringed by reefs; for instance, NOESSA, HARENCA, and UCASTER, in Freycinet's charts. The above-mentioned islands have been coloured red, although the evidence is not very satisfactory. – North of Bourou the parallel line of the XULLA Isles extends: I have not been able to find out anything about them, excepting that Horsburgh (volume ii., page 543) says that the northern shore is surrounded by a reef at the distance of two or three miles; uncoloured. – MYSOL GROUP; the Kanary Islands are said by Forrest ("Voyage," page 130) to be divided from each other by deep straits, and are lined with coral-rocks; coloured red. – GUEBE, lying between Waigiou and Gilolo, is engraved as if fringed; and it is said by Freycinet, that all the soundings under five fathoms were on coral; coloured red. – GILOLO. In a chart published by Dalrymple, the numerous islands on the western, southern (BATCHIAN and the STRAIT OF PATIENTIA), and eastern sides appear fringed by narrow reefs; these reefs, I suppose, are of coral, for it is said in "Malte Brun" (volume xii., page 156), "Sur les cotes (of Batchian) comme DANS LES PLUPART des iles de cet archipel, il y a de rocs de medrepores d'une beaute et d'une variete infimies." Forrest, also (page 50), says Seland, near Batchian, is a little island with reefs of coral; coloured red. – MORTY Island (north of Gilolo). Horsburgh (volume ii., page 506) says the northern coast is lined by reefs, projecting one or two miles, and having no soundings close to them; I have left it uncoloured, although, as in some former cases, it ought probably to be pale blue. – CELEBES. The western and northern coasts appear in the charts to be bold and without reefs. Near the extreme northern point, however, an islet in the STRAITS OF LIMBE, and parts of the adjoining shore, appear to be fringed: the east side of the bay of MANADO, has deep water, and is fringed by sand and coral ("'Astrol.' Voyage," Hydrog. Part, pages 453-4); this extreme point, therefore, I have coloured red. – Of the islands leading from this point to Magindanao, I have not been able to find any account, except of SERANGANI, which appears surrounded by narrow reefs; and Forrest ("Voyage," page 164) speaks of coral on its shores; I have, therefore, coloured this island red. To the eastward of this chain lie several islands; of which I cannot find any account, except of KARKALANG, which is said by Horsburgh (volume ii., page 504) to be lined by a dangerous reef, projecting several miles from the northern shore; not coloured.

ISLANDS NEAR TIMOR.

The account of the following islands is taken from Captain D. Kolff's "Voyage," in 1825, translated by Mr. W. Earl, from the Dutch. – LETTE has "reefs extending along shore at the distance of half a mile from the land." – MOA has reefs on the S.W. part. – LAKOR has a reef lining its shore; these islands are coloured red. – Still more eastward, LUAN has, differently from the last-mentioned islands, an extensive reef; it is steep outside, and within there is a depth of twelve feet; from these facts, it is impossible to decide to which class this island belongs. – KISSA, off the point of Timor, has its "shore fronted by a reef, steep too on the outer side, over which small proahs can go at the time of high water;" coloured red. – TIMOR; most of the points, and some considerable spaces of the northern shore, are seen in Freycinet's chart to be fringed by coral-reefs; and mention is made of them in the accompanying "Hydrog. Memoir;" coloured red. – SAVU, S.E. of Timor, appears in Flinders' chart to be fringed; but I have not coloured it, as I do not know that the reefs are of coral. – SANDALWOOD Island has, according to Horsburgh (volume ii., page 607), a reef on its southern shore, four miles distant from the land; as the neighbouring sea is deep, and generally bold, this probably is a barrier- reef, but I have not ventured to colour it.

N.W. COAST OF AUSTRALIA.

It appears, in Captain King's Sailing Directions ("Narrative of Survey," volume ii, pages 325-369), that there are many extensive coral-reefs skirting, often at considerable distances, the N.W. shores, and encompassing the small adjoining islets. Deep water, in no instance, is represented in the charts between these reefs and the land; and, therefore, they probably belong to the fringing class. But as they extend far into the sea, which is generally shallow, even in places where the land seems to be somewhat precipitous; I have not coloured them. Houtman's Abrolhos (latitude 28 deg S. on west coast) have lately been surveyed by Captain Wickham (as described in "Naut. Mag." 1841, page 511): they lie on the edge of a steeply shelving bank, which extends about thirty miles seaward, along the whole line of coast. The two southern reefs, or islands, enclose a lagoon-like space of water, varying in depth from five to fifteen fathoms, and in one spot with twenty-three fathoms. The greater part of the island has been formed on their inland sides, by the accumulation of fragments of coral; the seaward face consisting of nearly bare ledges of rock. Some of the specimens, brought home by Captain Wickham, contained fragments of marine shells, but others did not; and these closely resembled a formation at King George's Sound, principally due to the action of the wind on calcareous dust, which I shall describe in a forthcoming part. From the extreme irregularity of these reefs with their lagoons, and from their position on a bank, the usual depth of which is only thirty fathoms, I have not ventured to class them with atolls, and hence have left them uncoloured. – ROWLEY SHOALS. These lie some way from the N.W. coast of Australia: according to Captain King ("Narrative of Survey," volume i., page 60), they are of coral-formation. They rise abruptly from the sea, and Captain King had no bottom with 170 fathoms close to them. Three of them are crescent-shaped; they are mentioned by Mr. Lyell, on the authority of Captain King, with reference to the direction of their open sides. "A third oval reef of the same group is entirely submerged" ("Principles of Geology," book iii. chapter xviii.); coloured blue. – SCOTT'S REEFS, lying north of Rowley Shoals, are briefly described by Captain Wickham ("Naut. Mag." 1841, page 440): they appear to be of great size, of a circular form, and "with smooth water within, forming probably a lagoon of great extent." There is a break on the western side, where there probably is an entrance: the water is very deep off these reefs; coloured blue.

Proceeding westward along the great volcanic chain of the East Indian Archipelago, SOLOR STRAIT is represented in a chart published by Dalrymple from a Dutch MS., as fringed; as are parts of FLORES, of ADENARA, and of SOLOR. Horsburgh speaks of coral growing on these shores; and therefore I have no doubt that the reefs are of coral, and accordingly have coloured them red. We hear from Horsburgh (volume ii., page 602) that a coral-flat bounds the shores of SAPY Bay. From the same authority it appears (page 610) that reefs fringe the island of TIMOR-YOUNG, on the N. shore of Sumbawa; and, likewise (page 600), that BALLY town in LOMBOCK, is fronted by a reef, stretching along the shore at a distance of a hundred fathoms, with channels through it for boats; these places, therefore, have been coloured red. – BALLY Island. In a Dutch MS. chart on a large scale of Java, which was brought from that island by Dr. Horsfield, who had the kindness to show it me at the India House, its western, northern, and southern shores appear very regularly fringed by a reef (see also Horsburgh, volume ii., page 593); and as coral is found abundantly there, I have not the least doubt that the reef is of coral, and therefore have coloured it red.