Bivalve oyster shell

Devil’s Toe Nail

This is a ‘classic’ bivalve shell from the Blue Lias around Lyme Regis. This is not, as folklore might have it, the gnarled toe nail from some long lost monster! It is a humble and common oyster that sat on the sea bed with the larger heavier shell acting as an anchor. It filtered sea water for food. Look carefully and you’ll see occasional growth rings that are slightly stronger than the others – these may in fact be annual growth lines. They suggest that these animals were about five to six years in age when they died.

Find out more about bivalves on the molluscs pages.

Common name

Bivalve oyster shell

Scientific name

Gryphaea arcuata


Molluscs > Bivalves


Blue Lias

Time period

Lower Jurassic


200 million years

Where found

Lyme Regis

Found by



Lyme Regis Museum

Accession number