Bivalve oyster shell
Lots of oysters
Gryphaea is an oyster – you can tell that by the fact that the shell is made up of many fine layers one upon the other. This specimen also has many younger oysters growing on it. During the time when these animals were alive, the sea bed was soft and muddy but oysters like something firm to attach to when they first start to grow. Later, when they become large enough, they can drop off this surface and live on the sea bed filtering the water for food. In doing so, they form the hard surface for a new generation of oysters to grow.
Find out more about bivalves on the molluscs pages.