Bivalve shell and wood

Floating to freedom…for a while

These bivalve mussels were attached to the wood by ‘byssi’ (strong threads). However, sooner or later the wood became waterlogged or the colony of bivalves grew too heavy for it, and the whole lot sank to the sea bed. The sea bed was a stagnant and anoxic (low oxygen) place, so the bivalves would have perished quickly. The upside is that, as a result, the bivalves and log became very well-preserved.

Find out more about bivalves on the molluscs pages.

Common name

Bivalve shell and wood

Scientific name



Molluscs > Bivalves


Black Ven Marls

Time period

Lower Jurassic


190 million years

Where found

Black Ven, Charmouth

Found by

Found by Paul C Ensom in 1982


Dorset County Museum, Dorchester

Accession number