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Updated: June 24, 2025
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.
Hence it seems that along this coast, as at Bermuda and at Keeling Atoll, submarine and subaerial deposits are contemporaneously in process of formation, from the disintegration of marine organic bodies. The extent of these deposits, considering their origin, is very striking; and they can be compared in this respect only with the great coral-reefs of the Indian and Pacific Oceans.
But how did the coral-reefs rise till they became cliffs at Bristol and mountains in Yorkshire? The earthquake steam, I suppose, raised them.
More reliable information is, however, needed concerning these volcanoes. It is a remarkable circumstance that all the oceanic islands which are not coral-reefs are composed of volcanic rocks; and many of these oceanic islands, as well as others lying near the shores of the continents, contain active volcanoes.
When the "norte" blows fiercely you can hardly keep your feet in the streets of Vera Cruz, and vessels drag their anchors or break from their moorings in the ill-protected harbour, and are blown out to sea lucky if they escape the ugly coral-reefs and sand-banks that fringe the coast.
Such a contribution to the story of the "making of science" may be furnished in respect to Darwin's famous theory of coral-reefs, and the clearly reasoned treatise in which it was first fully set forth. The subject of corals and coral-reefs is one concerning which much popular misconception has always prevailed.
In the Southern Pacific there are only a few reefs beyond the line of the tropics, but Houtmans Abrolhos, on the western shores of Australia in latitude 29 deg S., are of coral formation. The proximity of volcanic land, owing to the lime generally evolved from it, has been thought to be favourable to the increase of coral-reefs.
There are many such lagoons, and this one, called by the fish-world, "Coral-Land," because of the beautiful coral within its depths, was only one of many coral-lands, for coral-islands, and coral-reefs are found everywhere in tropical seas. Sometimes these coral-reefs are found near the shores of large islands, or continents, and then they are called Shore-Reefs.
Allan, it appears that the greater number, namely PLATTE, ALPHONSE, COETIVI, GALEGA, PROVIDENCE, ST. PIERRE, ASTOVA, ASSOMPTION, and GLORIOSO, are low, formed of sand or coral-rock, and irregularly shaped; they are situated on very extensive banks, and are connected with great coral-reefs. Galega is said by Dr. Allan, to be rather higher than the other islands; and St.
These nulliporae, which are hard, very simply-organized sea-plants, play an analogous and important part in protecting the upper surfaces of coral-reefs, behind and within the breakers, where the true corals, during the outward growth of the mass, become killed by exposure to the sun and air.
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