Bivalve oyster shell

Additional images

Evolving oysters

Oyster shells changed through time as the animals evolved. Gryphaea shapes differ in Lower and Upper Jurassic rocks, becoming noticably larger or dilated (hence the species name dilatata). 

Oysters are bivalves, of which there are two different kinds. Mussels, scallops and clams have a solid, hard shell, whereas the shell of the oyster is made of many fine layers.

Find out more about bivalves on the molluscs pages.

Common name

Bivalve oyster shell

Scientific name

Gryphaea [Bilobissa] dilatata

Type

Molluscs > Bivalves


Strata

Oxford Clay

Time period

Upper Jurassic

Age

160 million years

Where found

Jordan's Cliff, near Weymouth

Found by

Unknown

Museum

Dorset County Museum, Dorchester

Accession number

DCM.G.02799