Coral Reefs

Page 102

The northern NATUNAS and the ANAMBAS Islands are represented in the charts on a large scale, published in the "Atlas of the Voyage of the 'Favourite'," as fringed by reefs of coral, with very shoal water within them.--TUMBELAN and BUNOA Islands (1 deg N.) are represented in the English charts as surrounded by a very regular fringe.-- ST. BARBES (0 deg 15' N.) is said by Horsburgh (volume ii., page 279) to be fronted by a reef, over which boats can land only at high water.--The shore of BORNEO at TUNJONG APEE is also fronted by a reef, extending not far from the land (Horsburgh, volume ii., page 468). These places I have coloured red; although with some hesitation, as the water is shallow. I might perhaps have added PULO LEAT, in Gaspar Strait, LUCEPARA, and CARIMATA; but as the sea is confined and shallow, and the reefs not very regular, I have left them uncoloured.

The water shoals gradually towards the whole west coast of BORNEO: I cannot make out that it has any reefs of coral. The islands, however, off the northern extremity, and near the S.W. end of PALAWAN, are fringed by very distant coral-reefs; thus the reefs in the case of BALABAC are no less than five miles from the land; but the sea, in the whole of this district, is so shallow, that the reefs might be expected to extend very far from the land. I have not, therefore, thought myself authorised to colour them. The N.E. point of Borneo, where the water is very shoal, is connected with Magindanao by a chain of islands called the SOOLOO ARCHIPELAGO, about which I have been able to obtain very little information; PANGOOTARAN, although ten miles long, entirely consists of a bed of coral-rock ("Notices of E. Indian Arch." page 58): I believe from Horsburgh that the island is low; not coloured.--TAHOW BANK, in some old charts, appears like a submerged atoll; not coloured. Forrest ("Voyage," page 21) states that one of the islands near Sooloo is surrounded by coral-rocks; but there is no distant reef. Near the S. end of BASSELAN, some of the islets in the chart accompanying Forrest's "Voyage," appear fringed with reefs; hence I have coloured, though unwillingly, parts of the Sooloo group red. The sea between Sooloo and Palawan, near the shoal coast of Borneo, is interspersed with irregular reefs and shoal patches; not coloured: but in the northern part of this sea, there are two low islets, CAGAYANES and CAVILLI, surrounded by extensive coral-reefs; the breakers round the latter (Horsburgh, volume ii., page 513) extend five or six miles from a sandbank, which forms the only dry part; these breakers are steep to outside; there appears to be an opening through them on one side, with four or five fathoms within: from this description, I strongly suspect that Cavilli ought to be considered an atoll; but, as I have not seen any chart of it, on even a moderately large scale, I have not coloured it. The islets off the northern end of PALAWAN, are in the same case as those off the southern end, namely they are fringed by reefs, some way distant from the shore, but the water is exceedingly shallow; uncoloured. The western shore of Palawan will be treated of under the head of China Sea.


A chart on a large scale of APPOO SHOAL, which lies near the S.E. coast of Mindoro, has been executed by Captain D. Ross: it appears atoll-formed, but with rather an irregular outline; its diameter is about ten miles; there are two well-defined passages leading into the interior lagoon, which appears open; close outside the reef all round, there is no bottom with seventy fathoms; coloured blue.--MINDORO: the N.W. coast is represented in several charts, as fringed by a reef, and LUBAN Island is said, by Horsburgh (volume ii., page 436), to be "lined by a reef."--LUZON: Mr. Cuming, who has lately investigated with so much success the Natural History of the Philippines, informs me, that about three miles of the shore north of Point St. Jago, is fringed by a reef; as are (Horsburgh, volume ii., page 437) the Three Friars off Silanguin Bay.

Charles Darwin

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