ISLAND, a body of land entirely sur rounded by water. Islands are of very differ ent extent and surface, and some are so large that physical geographers have doubted whether they should be called continents; this, however, is a mere matter of definition. The great masses of land forming the Eastern and West ern Continents are in reality islands. A con venient distinction is established by restricting the application of the noun, continent to North, Central and South America, Europe, Asia and Africa; designating Australia as a continental island; and classing Greenland (estimated area 826,000 square miles) as simply the largest of the islands, strictly so called. The following table shows the relative areas of other large islands: A cluster of several islands is called an archipelago. The principal clusters in the At lantic are the West Indies, the Azores, the Canaries, the Hebrides, Orkneys, Shetlands, etc. But the great world of islands is in the Pacific, and some modern writers consider them as forming a fifth division of the world, includ ing the Eastern Archipelago, Polynesia and Australia, to which they have given the name of Oceania. A large island is a continent in
miniature, with its chains of mountains, its rivers, lakes, and is often surrounded by a train of islets. The rivers of islands are in general little more than streams or torrents, and the smaller islands are often uninhabitable from want of water; but they serve as haunts and breeding-places of innumerable sea4birds. There are islands in rivers and lakes as well as in the sea. In rivers they are often formed by the division of the stream into various branches, and often by accumulations of earth brought down and deposited around a rocky base. Ex amples are not wanting of floating islands, which are formed by the roots of plants and trees in terlacing with each other, and thus constituting a support for deposits of successive layers of earth. The Pacific contains a great number of low islands having their basis formed of coral reefs, these reefs being produced by the labors of innumerable coral-animals or zoophytes.
See CORAL AND CORAL ISLANDS.