The South Coast Region - Southern England - page 111

FIG 108. Looking southeastwards along Chesil Beach (Fig. 99, h2 ) to the Isle of Portland
( h3 ). (Copyright Dae Sasitorn & Adrian Warren/www.lastrefuge.co.uk)
The Isle of Portland is connected to the mainland by Chesil Beach ( h2 ), a remark-
able coastal feature (Fig. 108). It is a coast-parallel gravel barrier some 28 km long,
and for most of its length it is separated from the mainland by the tidal lagoon known
as the Fleet. The pebbles are roughly pea-sized at the northwestern end of the beach at
West Bay, and potato-sized at the Portland end. The larger pebbles are thought to be
transported the longest distances along the beach because of the impact of the prevail-
ing storm waves on their larger surface area. Local folklore has it that smugglers could
tell exactly where along the beach they had landed just by looking at the size of the
pebbles.
Chesil Beach is one of several large gravel landforms that occur along the South
Coast. During the last (Ipswichian) interglacial, about 125,000 years ago, sea level was
slightly higher than now, and the coastal slope was eroded by storms and landslips just
as today. During the subsequent cold phases of the Ice Age, the former coastal debris
would have been spread widely by river action over the areas now covered by the sea,
and was then transported inland again by the rising sea during the most recent (Flandri-
an) sea-level rise. Chesil Beach was formed about 10,000 years ago, but is constantly
being reshaped by the waves. It seems that the beach is currently moving inland over
the tidal muds of the Fleet, as its outer face often reveals peats that appear to have
formed in the Fleet and then been over-run by the gravel ridge migrating landwards.