5,000 years old, 28 kilometres long and made of 180 billion pebbles – meet the finest barrier beach in Europe.
Chesil is one of our most eye-catching landforms, a long curving strip of pebbles 160 metres wide. Connecting the island of Portland to the mainland Dorset coast at Abbotsbury, and extending to West Bay, it separates the sea from the tranquil Fleet Lagoon behind. Its peacefulness and isolation belies a stormy past linked to shipwrecks and massive rises in sea level.
Around 25,000 years ago, at the peak of the last icy ‘glacial’ phase, the sea was about 120 metres below its present level and the shoreline was miles further out. As the seas warmed and the ice melted, sea levels rose rapidly, eroding the loose sand and gravel deposits in its path.
This created a ridge of sands and shingle, washed over from time to time by larger pebbles. This barrier ridge was steadily pushed onshore by the rising waters until it eventually reached its present position approximately 5,000 years ago.
Visitors today will spot that the beach pebbles gradually change size from east to west. The change comes from different strength tidal currents along the shore, which gradually move the smaller pebbles westwards.
The coastline along Chesil Beach can be treacherous, a fact reflected in the local name ‘Deadman’s Bay’. In November 1872, the Royal Adelaide, an iron sailing ship bound for Australia, misjudged its course in a storm and was washed ashore on Chesil. In dramatic scenes most of the passengers were rescued by a fragile ship-to-shore line. The cargo attracted looters from nearby towns and soon found its way into local houses.