Our Fossils The fossils found on Charmouth Beach are the remains of sea creatures that lived 185 million years ago in the Jurassic period. The Jurassic ecosystem would have followed the same basic rules as modern ecosystems. Large predators like ichthyosaurs would have been at the top of the food chain feeding on the smaller and more commonly found ammonites and belemnites. The lower end of the food chain included creatures like Gryphaea and Crinoids that fed on tiny plankton. Visit us at the centre to learn more. Below is a selection of the most popular and common fossils from Charmouth. These are the sorts of things you might find if you come fossil hunting with us.
Ammonites Ammonites were free swimming creatures related to squid and octopuses. Like these modern relatives they would have been predators, catching prey with long tentacles. Their shell was divided up into chambers filled with liquid and gas, which kept them buoyant.
Belemnite Belemnites were squid-like creatures that first appeared in our oceans over 300 million years ago. They became extinct about 65 million years ago, at the same time the dinosaurs died out. They were carnivorous and free swimming. They had a long bullet shaped body with a hard internal skeleton called a guard. The guard was situated towards the tail end of the creature and acted as a counterbalance for the head and tentacles. This part of the belemnite is what we commonly find on the beach as a fossil.
Crinoids ‘Pentacrinities fossilis’ The body consists of a long stem or stalk with the mouth, organs and five branching arms at the top. The arms are covered with small, sticky tube feet that the animal uses to catch tiny plants and animals (plankton) that drift along in the sea. (right: present day feather star)
Gryphaea ‘The Devils toenails’ The large curved bottom shell of Gryphaea is often found on its own because bivalve shells tend to separate after the animals die. Before they were identified as fossils of seashells the large half of Gryphaea were known in folklore as the “Devil’s Toenails” because they resemble old and overgrown nail clippings !
Fossil wood
Giant Marine Reptiles
Some fossils of marine reptiles include their stomach contents, revealing to scientists what they ate. Plesiosaurs mostly ate fish while ichthyosaurs preferred Ammonites and Belemnites.
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Ammonites are a well known fossil and easily recognised by their coiled shell. They first appeared around 400 million years ago and became a very successful group of animals. They died out around the same time as the dinosaurs about 65 million years ago.
Pentacrinites is a type of crinoid or ‘sea lily’. These creatures were not plants as their name suggests, but animals related to star fish and sea urchins. 
They have lived in our oceans for millions of years and can still be found today. They lived attached to the sea bed or to the underside of drift wood.
Gryphaea had two shells, very similar to their distant relatives the present day oysters. They rested on the sea bed on top of the muddy sediment. The larger, curved part of the shell would rest on the bottom with the small lid on top. When feeding the creature would open its shell and let sea water flow in and out. Any plankton (tiny plants and animals) that were in the sea water would have been filtered out and eaten.
In the Lower Jurassic the nearest land to what would become Charmouth would have been South Wales, London or possibly Dartmoor. Rivers would have washed logs from dead trees out to sea, and these would have eventually sunk and become fossilised with the sea creatures. The land environment would have looked quite barren, covered in hard ferns the size of trees, cycads and conifers. There were no flowering plants or grasses because they had not yet evolved. 
Giant marine reptiles such as Ichthyosaurs and Plesiosaurs were the dominant predators in the Lower Jurassic oceans. They were cousins of the dinosaurs but were adapted for living in the sea. Marine reptiles would have had to surface to breathe just like marine mammals. Plesiosaurs are thought to have returned to land to lay eggs but there is evidence to suggest that Ichthyosaurs were so well adapted for life in the sea that they gave birth to live young! This is strange when compared to the egg laying reptiles we live alongside today!
Ichthyosaurs are famous for looking just like sharks or dolphins and Plesiosaurs became well known when it was suggested one was living in Loch Ness.
