Bivalve shell

Why green?

The Upper Greensand gets its colour from a mineral, glauconite, which only forms in the sea. The glauconite and oyster shells tell us that this rock formed from sand deposited on a seabed. The glauconite rapidly oxidises on contact with the air and so the green colour is only visible in freshly-exposed rocks.

Find out more about bivalves on the molluscs pages.

Common name

Bivalve shell

Scientific name

Exogyra obliquata

Type

Molluscs > Bivalves


Strata

Upper Greensand

Time period

Lower Cretaceous

Age

105 million years

Where found

Up Sydling Farm

Found by

Unknown

Museum

Dorset County Museum, Dorchester

Accession number

DCM.G.08361