ISLAND (AS. igiond, Fglond, Icel. ryland, Ger. Eiland, from AS. ig? ig, Icel. cy, 1111G.
•a, Ger. A u, island ; connected with AS. Goths aLuu, IIIIG. cilia. Lat. aqua, water + Icel. land, OHO. hunt, Ger. Land, land ; connected with Ir. lain, land, Welsh llan, land, OChureh Slay. frrdnnm. waste land. OPruss. lindan, valley; intlueneed by popular etymology with the unre lated isle). A relatively small holy of land en tirely surrounded by water. Primarily it differs from a continent only in size, although continents have a physical and biological individuality which islands do not possess. shl MIS are formed in •arions ways. Those of continental character are separated by short stretches of usually shallow water from the mainland with which they have a geological similarity. They may be formed either by marine erosion. or by subsidence of the coast beneath ocean level. The small islands off Norway, Scotland, Maine, and Patagonia are to be regarded as the remnants of hills and mountains, of which the basal portions and inter vening valleys have been 'drowned' by a general subsidence. The British Isles, Sicily. and Japan represent larger land masses. Whose former union with the mainland is indicated by submarine banks; Madagascar, on the other hand, is sepa rated by a deep channel from the African coast. Another type of continental islands Owes its origin to the constructive work of rivers, such as the islands at the mouth of the Nile and the Mississippi (see DELTA), or to ocean currents, such as the sandbars along the Atlantic coast of the United States. Islands of coral formation are usually low and limited to the warmer re gions of the oceans. (See CORAL ISLAND AND
CORAL REEF.) Volcanic islands, consisting of active or extinct lava-cones, occur in great num bers in the Pacific and Indian oceans, while in the Atlantic they are represented by Saint Helena, Ascension, and the Azores. Submarine eruptions to the construction of cones above sea-level have taken place in recent times. The island of Johanna Bogoslava, in Alaska, ap peared in 1796, and four years later had grown to a height of 3000 feet. Another noted in stance is Graham Island (F•rdinandea) in the Mediterranean. ieb was thrown up in 1831, reaching a height of 200 feet, and with a cir cumference of three miles. This island soon dis appeared. Oceanie islands—i.e. those situated far front continental lands—with but few excep tions, are of vol•anie or coral growth.
Islands are subject to changes of form and contour by various physical agencies. They may be gradually consumed, owing to the erosive ac tion of waves and currents, until their former existence is made known only by a submarine platform. Helgoland, in the North Sea, has suffered thus for many centuries; and the eastern coast of England is wasting at a rapid rate. Volcanic islands are liable to destruetion by violent explosions. such as that occurring at Krakatoa in 18g3. Under certain conditions, islands lying near the coasts of continents may he united to the latter; the peninsula of Shan tung, once insulated. has been connected with the mainland by the growth of the IToanglio delta.