Problems of Coral Reefs

Abstract

RECENT work on coral reefs has established firmly the part played by submergence in the production of encircling and barrier reefs. At the same time, such reefs are shown to be based on extensive platforms, from which there is a further descent to oceanic waters. Mr. T. W. Vaughan points out (Amer. Journ. of Science, vol. xli., 1916, p. 134) that the banks off Newfoundland, Nova Scotia, and Cape Cod “would furnish proper habitats for reef-building corals did they not lie outside the life-zone of such organisms,” while the corresponding plateaus of Florida and the Central American coast support many reefs. He attributes the general overflowing of the marginal land areas in recent geological time to “some diastrophic change in the earth,” and is unwilling to accept Glacial control as accounting for all the facts. His paper is an introduction to one on the “Relations of Coral Reefs to Crust Movements in the Fiji Islands,” by E. C. Andrews, of Sydney (ibid., p. 135), in which submergence is regarded as essential to the formation of the Great Barrier Reef of Queensland, while the barrier reefs of the Fijis are reviewed as narrow growths rising from land areas that hase been recently submerged. Prof. R. A. Daly follows (ibid., p. 153) with a paper on “Problems of the Pacific Islands,” and emphasises, the presence of platforms one or two miles to one hundred miles in width as bases for the growth of reefs. He also considers the case of Queensland, and the numerous sections given, drawn to scale, are an important contribution to geography. “The problem of the coral reef,” he concludes, “is, in essence, the problem of the platform.” Mr. T. W. Vaughan, in the Journal of the Washington Academy of Sciences, vol. vi., 1916, p. 53, describes the association of platforms and reefs in the Virgin and Leeward Islands, where the platforms were moulded by marine erosion during Pleistocene time and then submerged, the changes of sea-level thus according with Daly's theory of Glacial control. Readers of NATURE will remember a recent consideration of this theory (vol. xcvii., p. igi).