FIJI. 9 Shore or attached reefs, sea or barrier reefs, beds, patches, or knolls of reef, with sunken rocks and sand-banks, so abound in Fiji and its neighbourhood as to make it an ocean labyrinth of unusual intricacy, and difficult of navigation. The coral formation found here to so vast an extent has long fur- nished an interesting subject for scientific research, and proved a plentiful source of ingenious conjecture; while the notion has found general fa- vour, that these vast reefs and islands owe their structure chiefly to a microscopic zoophyte, — the coral insect. Whether by the accumulated deposit of their exuvise, or by the lime-secretion of their gelatinous bodies, or the decomposition of those bodies when dead, these minute polypes, we are told, are the actual builders of islands and reefs ; the lapse of ages being required to raise the edifice to the level of the highest tide ; after which, the formation of a soil by drifting substances, the planting of the island with seeds borne by birds or washed up by the waves, and, lastly, the arrival of inhabitants, are all set forth in due order with the exactness of a formula based upon the simplest observation. A theory so pretty as this could not fail to become popular, while men of note have strengthened it by the authority of their names. Close and con- stant inspection, however, on the part of those who have had the fullest opportunity for research, is altogether opposed to this pleasingly in- teresting and plausible scheme. Wasting and not growth, ruining and not building up, characterize the lands and rock-beds of the southern seas. Neither does the ingenious hypothesis of Darwin, that equal gain and loss — rising in one part, and depression in another — are taking place, seem to be supported by the best ascertained facts ; for the annular con- figuration of reef which this theory pre-supposes, is by no means the most general. " In all the reefs and islands of coral that I have ex- amined," writes Commodore Wilkes, " there are unequivocal signs that they are undergoing dissolution ; " * a conclusion in which my own ob- servation leads me entirely to concur. The operation of the polyps is undoubtedly seen in the beautiful mad- repores, brain-corals, and other similar structures, which, still living, cover and adorn the surface ; " but a few inches beneath, the reef is in- variably a collection of loose materials, and shows no regular coralline structure, as would have been the case if it had been the work of the lithophyte." f These corals rarely reach the height of three feet, while many never exceed so many inches. The theory stated above assumes that the polyps work up to the height of a full tide. Such is not the
- " United States Exploring Expedition," vol. Iv., chap. "viii. t Ibid.
