Hotspots: The Jurassic Sea and Fossils, Sunstones, Ammonite Graveyard, Devil's Pavement, Giant Ammonites
The Graveyard of Ammonites
One layer of rock along Monmouth Beach at Seven Rock Point has so many ammonites in it hat it has become known as the “Graveyard of Ammonites”. No one really knows why so many ammonite carcasses have accumulated here, but it could have been the result of the animals dying on mass after breeding, or perhaps they were suffocated by sediment pouring into the sea from rivers after a deluge.
Giant Ammonites litter Monmouth Beach. These are not collectable as they have formed part of the rock, the original shell being transformed into crystals of calcite, formed from Calcium Carbonate. Many show the chambers making up the ammonites coil. If you’re lucky, you may find one that has filled with smaller ammonites before it became fossilised.
A type of Jurassic oyster can be found in a layer of rock on the shore at Seven Rock Point. When worn away they look like toenail clippings and have earned themselves the name, the “Devils Toenail”. The ledge in which they are found has become known as the “Devils Pavement”.
Some rocks on the beach at Seven Rock Point have a layer of Jurassic Beef coating them (so called as to look as though it has the texture of beef). In a few unique cases the Beef has formed unique characteristics. These often look like medusa heads earning themselves the name “Sun Stones”.
The Jurassic Sea and Fossils
The Jurassic clays around this area formed in a deep tropical sea, the soft muddy bottom of which was often stagnant, creating a sulphurous and anoxic environment, the best conditions for preserving the shells, bones and even soft tissue of dead prehistoric creatures.
It is these stagnant seabed conditions which have given the cliffs around Lyme Regis and Charmouth their dark colour, and it explains why the sediments found here are some of the richest fossil bearing deposits to be found anywhere along the Jurassic Coast.
Coastal Features: The Great Unconformity and The Cretaceous Blanket, Cow Stones
The Great Unconformity and The Cretaceous Blanket
The sediments which make up the Jurassic Coastline were deposited in the following order, Triassic, Jurassic and Cretaceous, with the oldest rock, the Triassic sitting at the at the bottom of the pile.
The large fallen rocks on the shore were often mistaken by sailors from their ships as looking like cows, earning then the name, Cow Stones. These are in fact large sandy concretions derived from the Greensand, part of the Cretaceous layer of rocks forming the “Cretaceous Blanket” along this part of the Jurassic Coastline. Cow Stones often contain trace fossils from the burrows and tracks left behind by marine sea creatures around 100 million years ago.
Coastal Visitor Centre
Charmouth Heritage Coast Centre
Town/Village or Area:
Tourist Info Centres
in this Area: Undercliff Nature Reserve
Undercliff Nature Reserve
The 5 miles (8 km) of undercliff between Seaton and Lyme Regis provides a natural oasis for wildlife. The area supports Britain’s largest self-sown Ash forest and is one of the most remote parts of the South West Coast Path, providing a challenging walk through a wilderness like landscape. The microclimate offered by the shelter from the cliffs, land-slipped gullies and trees provides a refuge for all manner of plants and animals.