Coral Reefs

Page 88

They consist of five very low islands of coral-formation, two of which are connected by a reef, with deep water close to it. They do not surround a lagoon, but are so placed that a line drawn through them includes an oval space, part of which is shallow; these islets, therefore, probably once (as is the case with some of the islands in the Caroline Archipelago) formed a single atoll; but I have not coloured them.--DANGER Island (10 deg S., 166 deg W.); described as low by Commodore Byron, and more lately surveyed by Bellinghausen; it is a small atoll with three islets on it; blue.--CLARENCE Island (9 deg S., 172 deg W.); discovered in the "Pandora" (G. Hamilton's "Voyage," page 75): it is said, "in running along the land, we saw several canoes crossing the LAGOONS;" as this island is in the close vicinity of other low islands, and as it is said, that the natives make reservoirs of water in old cocoa-nut trees (which shows the nature of the land), I have no doubt it is an atoll, and have coloured it blue. YORK Island (8 deg S., 172 deg W.) is described by Commodore Byron (chapter x. of his "Voyage") as an atoll; blue.--SYDNEY Island (4 deg S., 172 deg W.) is about three miles in diameter, with its interior occupied by a lagoon (Captain Tromelin, "Annal. Marit." 1829, page 297); blue.--PHOENIX Island (4 deg S., 171 deg W.) is nearly circular, low, sandy, not more than two miles in diameter, and very steep outside (Tromelin, "Annal. Marit." 1829, page 297); it may be inferred that this island originally contained a lagoon, but I have not coloured it.--NEW NANTUCKET (0 deg 15' N., 174 deg W.). From the French chart it must be a low island; I can find nothing more about it or about MARY Island; both uncoloured.--GARDNER Island (5 deg S., 174 deg W.) from its position is certainly the same as KEMIN Island described (Krusenstern, page 435, Appen. to Mem., published 1827) as having a lagoon in its centre; blue.


CHRISTMAS Island (2 deg N., 157 deg W.). Captain Cook, in his "Third Voyage" (Volume ii., chapter x.), has given a detailed account of this atoll. The breadth of the islets on the reef is unusually great, and the sea near it does not deepen so suddenly as is generally the case. It has more lately been visited by Mr. F.D. Bennett ("Geographical Journal," volume vii., page 226); and he assures me that it is low and of coral-formation: I particularly mention this, because it is engraved with a capital letter, signifying a high island, in D'Urville and Lottin's chart. Mr. Couthouy, also, has given some account of it ("Remarks," page 46) from the Hawaiian "Spectator"; he believes it has lately undergone a small elevation, but his evidence does not appear to me satisfactory; the deepest part of the lagoon is said to be only ten feet; nevertheless, I have coloured it blue.--FANNING Island (4 deg N., 158 deg W.) according to Captain Tromelin ("Ann. Maritim." 1829, page 283), is an atoll: his account as observed by Krusenstern, differs from that given in Fanning's "Voyage" (page 224), which, however, is far from clear; coloured blue.-- WASHINGTON Island (4 deg N., 159 deg W.) is engraved as a low island in D'Urville's chart, but is described by Fanning (page 226) as having a much greater elevation than Fanning Island, and hence I presume it is not an atoll; not coloured.--PALMYRA Island (6 deg N., 162 deg W.) is an atoll divided into two parts (Krusenstern's "Mem. Suppl." page 50, also Fanning's "Voyage," page 233); blue.--SMYTH'S or Johnston's Islands (17 deg N., 170 deg W.). Captain Smyth, R.N., has had the kindness to inform me that they consist of two very low, small islands, with a dangerous reef off the east end of them. Captain Smyth does not recollect whether these islets, together with the reef, surrounded a lagoon; uncoloured.


HAWAII; in the chart in Freycinet's "Atlas," small portions of the coast are fringed by reefs; and in the accompanying "Hydrog. Memoir," reefs are mentioned in several places, and the coral is said to injure the cables. On one side of the islet of Kohaihai there is a bank of sand and coral with five feet water on it, running parallel to the shore, and leaving a channel of about fifteen feet deep within.

Charles Darwin

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