The Jurassic Coast World Heritage Site comprises 95 miles of southern England's most dramatic coastline. It stretches from Studland Bay, opposite Poole Harbour, to Exmouth in East Devon. This length encompasses a generous collection of famous seaside landmarks including Old Harry Rocks, Durdle Door, Portland, Chesil Beach and Lulworth Cove.
The area has the status of a UNESCO World Heritage Site because it is recognised is having physical significance at a global level. There are less than 200 such sites across the world, and they include the Grand Canyon and the Great Barrier Reef.
The coast is unique because it displays geology from the Triassic, Jurassic and Cretaceous periods - spanning 185 million years of history in less than 100 miles of seashore.
A Geological Treasure Trove
Geology - the study of rocks - might not sound a very exciting subject. But on the Jurassic Coast the Earth's natural processes of rock formation are vividly displayed in cliff faces and rocky outcrops. For example, the cliffs at Peveril Point near Swanage clearly display the different layers of rock, laid down over hundreds of thousands of years.
Lulworth Cove is an excellent example of how a hard cliffs of Portland limestone have been penetrated by the sea. Having a created a narrow gap in the resistant rock, the powerful waters have carved a cove out of the softer clays behind. The result is beautiful natural harbour with a narrow entrance. It is one of the finest examples of such a landform in the world.
Chesil Beach is a very different landform. It is an 18 mile long barrier beach made of shingle. Over time it has grown eastwards, following the line of the coast until reaching the Isle of Portland. Behind it is the shallow Fleet, a tidal lagoon. A particular feature of this massive formation is the distribution of pebbles, which are evenly sorted by size along its length.
A Rich Source of Fossils
185 millions years of history are also represented by a rich fossil record. The cliffs along the coast have been mined for fossils for over two hundred years. The early British paleontologist Mary Anning (1799-1847) found the first complete ichthysaur ever discovered, near the seaside resort of Lyme Regis, after the skull was exposed by erosion.
There is a constant supply of new fossils being released onto the beaches of of the Jurassic Coast. Every year the sea batters the cliffs, particularly the soft rocks of Dorset, uncovering more and more remains of ancient creatures. At several places on the coast it is possible to see huge fossil ammonites, over 12 inches in diameter, still in situ in the rock.
Fossil collectors from the across the world flock to the Jurassic Coast, looking for opportunities to extend their collection by picking up fossils directly from the beach.
Continuing Erosion
The natural wonders of the Jurassic Coast have been formed by the force of the wind and the waves. These sames powers are still operating and the erosion continues. Old Harry Rocks, a series of natural stacks off Studland, were once connected to the land. Their soft chalk cliffs still retreat year after year and eventually the stacks will fall into the sea, to be replaced by newly created ones.
The strength of the sea is also demonstrated elsewhere. Peveril Point, near Swanage, is a rocky headland of Purbeck limestone. It's a natural defensive position and various military structures have been build upon in. A Second World War observation point, less than seventy years old, is now collapsing into the sea as the cliffs are undermined by the waves.
The National Trust and other other bodies who manage the coastline are working with nature, rather than against it. Erosion can be slowed but rarely stopped, and these agencies accept that change will eventually happen.
The Jurassic Coast of Dorset and Devon is a jewel in England's crown of natural beauty. It is a popular holiday destination, with visitors from all over the world. But it is more than just a museum of geology - it is a living coastline, changing with the seasons and with the years.
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