LOUISIADE ARCHIPELAGO, a chain of islands in the Pacific Ocean, extending south-eastward from the easternmost promontory of New Guinea, and included in the Australian territory of Papua (British New Guinea). The islands number over eighty, and are interspersed with reefs. They are rich in tropical forest products, and gold has been discovered on the chief island, Tagula or South-east (area 380 sq. m.) and on Misima or St Aignan. The natives are of Papuan type, and practise cannibalism. The islands were probably observed by Torres in 1606, but were named by L. A. de Bougainville in 1768 after Louis XV. LOUISIANA, one of the Southern States of the United States of America, lying on the N. coast of the Gulf of Mexico. Beginning on the N., its boundary follows eastward the parallel of 33° N., separating Louisiana from Arkansas; then descends the Mississippi river, separating it from the state of Mississippi, southward to 31°; passes eastward on this parallel to the Pearl river, still with the state of Mississippi on the E.; and descends this river to the Gulf. On the W. the Sabine river, from the Gulf to 32° N., and, thence to the parallel of 33°, a line a little W. of (and parallel to) the meridian of 94° W., separate Louisiana from Texas. Including islands in the Gulf, the stretch of latitude is approximately 4° and of longitude 5°. The total area is 48,506 sq. m., of which 3097 sq. m. are water surface (including 1060 sq. m. of landlocked coastal bays called "lakes"). The coast line is about 1500 m. _Physical Features._--Geologically Louisiana is a very recent creation, and belongs to the "Coastal Plain Province." Most of the rocks or soils composing its surface were formed as submarine deposits; the easternmost and southernmost parts are true river deposits. These facts are the key to the state's chorography. The average elevation of the state above the sea is only about 75 ft., and practically the only parts more than 400 ft. high are hills in Sabine, Claiborne and Vernon parishes. The physiographic features are few and very simple. The essential elements are five[1]: diluvial plains, coast marshes, prairies, "bluffs" and "pine-hills" (to use the local nomenclature). These were successive stages in the geologic process which has created, and is still actively modifying, the state. They are all seen, spread from N. to S., west of the Mississippi, and also, save only the prairies, in the so-called "Florida parishes" E. of the Mississippi.