Geology Site Account

The sea floor off Walton-on-the-Naze is rich in fossils. For over 200 years fishing and dredging operations have recovered many important finds from the London Clay, Red Crag, and more recent Ice Age sediments.

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Fossils from the London Clay

Fossils from the London Clay are found on the North Sea floor and the bones of several species of extinct mammals were obtained by dredging in the early nineteenth century. The most famous discovery was made off the Essex coast in 1844 when part of a lower jaw with teeth of a large but completely unknown mammal was found. The fossil was acquired by Essex amateur geologist John Brown who concluded that it was undoubtedly from the London Clay because it was a rich, deep brown colour, was heavily impregnated with minerals, and sparkling crystals of iron pyrite (fools gold) lined the pulp-cavity of the broken molar tooth. Brown passed it to his friend, the eminent palaeontologist Richard Owen, who, in 1845, described and named the beast Coryphodon and confidently stated, from the evidence of this single specimen, that it was a large, hoofed herbivore. Over thirty years later, in 1876, this description was vindicated when the great American dinosaur collector Othniel C. Marsh announced the discovery of a complete Coryphodon skeleton in the Rocky Mountains. It is now known that this animal must have weighed about 500 kilograms (half a ton), was about one metre (3 feet) high at the shoulder and 2.3 metres (76) long. It had a large skull with canine tusks and probably had a semi-aquatic life like todays hippopotamus. It lived about 50 million years ago and shared the coastal rainforest with crocodiles, turtles and horse-like mammals.

Fossils from the Red Crag

A number of bones from the Red Crag nodule bed have also been dredged up from the sea floor off Walton. Most impressive of these finds are three fossilised rostra or snouts from ziphoid whales. Related to sperm whales, ziphoid whales are a family of toothed whales that are 4 to 10 metres (12 to 30 feet) long and have the front of the head drawn out to suggest a beak. In the nineteenth century a well-preserved tooth of a mastodon, an extinct ancestor of the elephant was also found by dredging in this area. Mastodon teeth are known from the Red Crag of Suffolk but are rare in Essex. Like other teeth and bones from this bed these fossils have a beautiful natural polish that has not been satisfactorily explained.

Fossils dating from the Ice Age

The most common fossils on the floor of the North Sea are the bones and teeth of mammals that lived during the colder periods of the Ice Age when sea level was much lower and the land between Britain and Holland was low lying grassland and marsh. Tens of thousands of these fossils have been brought ashore by fishing boats working off the English coast, an example being the vertebra of a mammoth dredged up off Clacton and donated to Colchester Museum in 1923. Numerous teeth and bones of mammoth and other Ice Age mammals have been dredged off Walton and several outstanding mammoth teeth from here are in the Natural History Museum. These fossils are still being found today by local fisherman.

A 39 centimetre (15 inch) long fossilised rostrum or snout of a new species of ziphoid whale dredged up from off Walton-on-the-Naze in the early years of the twentieth century. The remarkable natural polish that Red Crag bones display can be clearly seen in this photograph. The fossil is at least five million years old and is on display in the Geology Gallery of Ipswich Museum. Photo © Essex Field Club