Almost the whole circumference of Sri Lanka is fringed by wide sandy beaches. Between Galle Point and Arugam Bay, a distance of 200 km, the ocean has regularized the southern coast: the result of coastal drift, influenced by the powerful current which flows, according to season, from the north-east or the south-west. Everywhere else the low-lying coastal areas are in process of change. The rivers carry down a mass of alluvial soil to the estuaries, and this is then swirled about by the currents and deposited in the form of sand-spits and offshore bars, or piled up into dunes which are stabilized by a rapid growth of vegetation. Here the geographer can recognized, at various stages of development, all the different forms of coastal deposition described in the textbooks. Sometimes an offshore bar will completely enclose a lagoon, which in time will degenerate into a swamp; but as a rule openings remain for the passage of the tides. In thinly populated areas the lagoons become a paradise for brilliantly coloured waders and web-footed birds, as in the Chundikkulam and Kokkilai National Parks. Apart from a few points on the coast where mangrove swamps have developed (Jaffna, Negombo and Ambalangoda lagoons) the coasts of Sri Lanka are almost entirely edged by immense palm-groves, with areca palms, talipots, coconut palms, palmyras and all the other species of these miraculous providers of man’s needs. In the north-east the jungle and scrub reach down almost to the edge of the deserted beaches.