Guyana has no well-defined shoreline or sandy beaches. Approaching the ocean, the land gradually loses elevation until it includes many areas of marsh and swamp. Seaward from the vegetation line is a region of mud flats, shallow brown water, and sandbars. Off New Amsterdam, these mud flats extend almost . The sandbars and shallow water are a major impediment to shipping, and incoming vessels must partially unload their cargoes offshore in order to reach the docks at Georgetown and New Amsterdam.