Chesil Beach (sometimes called Chesil Bank) is a 18 mile (29km) long, 200 metre wide and 18 metre high shingle tombolo in Dorset, southern England. The beach is part of the Jurassic Coast World Heritage Site. This tombolo connects the Isle of Portland, a limestone island in the English channel to Abbotsbury, though it continues eastwards to West Bay near Bridport, and it is the largest tombolo in the world. The beach is steep showing a clear storm beach (see: beach). Pebbles on the beach are graded, getting courser nearer Portland, and fishermen familiar with the beach claim to be able to tell their location from pebble size alone. The pebbles are mainly flint and chert from the Cretaceous rocks which make up this stretch of the Heritage Coast.
The origin of the beach has been argued over for some time, originally believed to be from the Budleigh Salterton pebble beds to the west and later from Portland to the south east. The differenced between the pebbles on the beach and nearby sources is now put down to the Flandrian isotactic sea level rise.
The beach provides shelter from the prevailing winds and waves for the towns of Weymouth and Fortuneswell, which otherwise would probably not exist.
From West Bay to Cliff End the beach is piled up against the cliff. At Cliff End a hollow forms behind the beach and at Abbotsbury a stretch of muddy saline (or brackish) water called The Fleet, which is often referred to as a lagoon, begins. The fleet is home to many wading birds and Abbotsbury Swannery, and fossils can be found in the mud.
The beach and the fleet, because of their proximity to the naval base on Portland, and the low population density of nearby areas was used for machine gun training and bouncing bomb testing in World War II.
