On Coral Reefs and Islands |
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accumulations action afford animal Apamama Archipelago Astræas atoll barrier reefs basaltic beach bottom breakers calcareous carbonate of lime cemented change of level channels character coast compact coral islands coral reefs coral rock coral zoophytes currents Darwin debris deep deposits depth detritus diameter distance east enclosed evidences of elevation extent facts Feejees feet high feet in height formation fragments fringing reef Group growing coral growth of coral harbor high islands high tide hundred feet inches inner reefs islets Kauai land latitude layers Lebu limestone low tide Maldives masses Metia Nairai nearly Oahu observed ocean outer reefs Pacific patches Paumotus polyps Porites Raraka reef-grounds reefs and islands remarkable Salomon Islands Samoa sand shallow shells shore platform side six feet slopes species square miles streams subsidence surface Tahiti Tarawan tion Tongatabu Upolu Vanua Levu vegetation volcanic waves wide zoophytes
Popular passages
Page 70 - And life, in rare and beautiful forms, Is sporting amid those bowers of stone, And is safe when the wrathful spirit of storms Has made the top of the wave his own...
Page 47 - ... talk of electrical forces, the first and last appeal of ignorance. Others call in the fishes of the seas, suggesting that they are the masons, and work with their teeth in the accumulation of the calcareous material. Very many of those who discourse quite learnedly on zoophytes and reefs, imagine that the polyps are mechanical workers, heaping up these piles of rock by their united labors ; and science still retains such terms as polypary, polypidom, as if each coral were the constructed hive...
Page 51 - The cactus, the lichen clinging to the rock, and the fungus in all its varieties, have their numerous representatives. Besides these forms imitating vegetation, there are gracefully modelled vases, some of which are three or four feet in diameter, made up of a network of branches and branchlets and sprigs of flowers. There are also solid coral hemispheres, like domes among the vases and shrubbery, occasionally ten, or even twenty feet in diameter, whose symmetrical surface is gorgeously decked with...
Page 45 - Perhaps the query might be best answered by another : How many of the various arts of civilized life could exist in a land where shells are the only cutting instruments — the plants in all but twenty-nine in number — but a single mineral...
Page 57 - The sea water and the ordinary food of the polyps are evidently the source from which the ingredients of coral are obtained. The same powers of elaboration which exist in other animals belong to polyps, for this function, as has been remarked, is the lowest attribute of vitality. Neither is it at all necessary to inquire whether the lime in sea water exists as carbonate or sulphate, or whether chloride of calcium takes the place of these.
Page 48 - Coral is never, therefore, an agglutination of grains made by the handywork of the manyarmed polyps: for it is no more an act of labor than bone-making in ourselves. And again, it is not a collection of cells into which the coral animals may withdraw for concealment, any more than the skeleton of a dog is its house or cell : for every part of the coral of a polyp in most reef-making species is enclosed within the polyp, where it was formed by the secreting process.* It is important that this point...
Page 60 - ... miles off its mouth to dip up fresh water alongside, there is a single porous species of Madrepora, (M. cribripora,) growing here and there in patches over a surface of dead coral rock or sand. In similar places about other regions, species of Porites are most common.
Page 71 - presents a scene of unequalled desolation. In stormy winters, huge blocks of stones are overturned or are removed from their native beds, and hurried up a slight acclivity to a distance almost incredible. In the winter of 1802, a tabular-shaped mass, eight feet two inches by seven feet, and five feet one inch thick, was dislodged from its bed, and removed to a distance of from eighty to ninety feet.
Page 51 - Trees of coral are well known ; and, although not emulating in size the oaks of our forests — for they do not exceed six or eight feet in height — they are gracefully branched, and the whole surface blooms with coral polypes in place of leaves and flowers.
Page 47 - It is not more surprising nor a matter of more difficult comprehension that the polyp should form coral, than that the quadruped should form its bones, or the mollusc its shell. The processes are similar, and so the result : in each case it is a simple animal secretion, a formation of stony matter from the aliment which the animal receives, produced by certain parts of the animal fitted for this secreting process. This power of secretion is the first and most common of those that belong to living...