Lt.Island frames the South Eastern entrance to Wellfleet Harbour which includes salt marsh, fresh water creeks and shifting islands of land. During the New and Full Moon at High Tide the rising water from the Bay cuts off s the Island from the mainland of Cape Cod. The rising and receding tides of up to 13 feet are the central element of the harbour bringing seawater rich in nutrients to the creatures that live in the varied habitats of the harbour,