BARREN ISLAND, a volcanic island in the Bay of Bengal. It has an irregularly circular form of about 2 m. in diameter, composed of an outer rim rising to a height of from 700 to 1000 ft., with a central cone the altitude of which is 1015 ft. This cone rises from a depth of 800 fathoms below the sea. It was active between 1789 and 1832, but has since been dormant.