Cardita is a genus of marine bivalves with both living species and extinct ones that are known as fossils. This is the case of specimen in the images from Vallhonesta (Sant Vicenç de Castellet) in Eocene terrain.
Cardita has medium to large size, round shape, wide and well-defined radial ribs, and umbos -the roughly conical initial part of each valve- that protrude from the hinge and separate each other.
[photos Jordi Badia, identification Josep Biosca]