Bivalve oyster shell
Oyster shells are distinctive in that they are built up of many fine layers. This specimen is unusual because it appears to have some of the soft tissue preserved in the hinge (the tip of the shell). Phosphorus is an essential element in animals’ diets – when it was released as this oyster decayed, it may have contributed to the mineral that replaced soft tissue.
Find out more about bivalves on the molluscs pages.