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The Parks / Prince Edward Island / Prince Edward Island National Park

The gradual rising of sea levels as the last Pleistocene ice sheet retreated northward cut off the low-lying island from the larger landmass. The estuaries of four main watersheds have cut shallow valleys into the 200 million-year-old rock to drain into coastal bays. The soft sand stone coastline is still being worn off by wind and water erosion at the rate of .5 to 1.0 metres annually. As far as 20 kilometres out, the water is no more than 15 metres deep. The general landscape features within the park boundaries include beaches and dunes comprising 37%, forested till uplands making up 39%, salt and fresh water wetlands totaling 15%, and non-forested fields and headlands accounting for 8%. Roads and other disturbed areas have affected about 16% of the park. The dune and beach system is varied; dunes back most of the beaches, but sandstone and siltstone cliffs border some. Beach sand has come primarily from the erosion of the shallow sea bottom, the cliffs and glacial debris - crystal, quartz, magnetite, and mica - carried along the coast by wind and currents to be deposited on shore. Usually sand bars move shoreward and build up the beaches, but during severe storms this process is reversed and dunes are undercut by washovers which drag sand back to the sea. The wind sweeping down from the north creates the small freshwater ponds or barachois where sand builds up and chokes off the open end of an inlet keeping out the salt water. Fresh water from rain, a stream or spring then creates a little land-locked lagoon that evolves into a pond habitat. Over the last 100 years offshore islands have been pushed landward by storms and currents to become a protective barrier. Cavendish Sandspit and Blooming Point, examples of this shifting landscape, may eventually be closed off creating barachois ponds.