Clams and Their Relatives Gallery

Fossil bivalves come in many different shapes and sizes. The largest, the extinct inoceramid clams, were as much as 6 feet in diameter and lived in colonies on the floor of a shallow ocean that covered the interior of North America during the Cretaceous Period. They are preserved in great numbers in the rocks of the Niobrara Chalk in western Kansas.
Pennyslvanian bivalves

Pennsylvanian Bivalves

Pennsylvanian bivalves in limestone, collected near Bonner Springs.

Volviceramus fossil

Volviceramus — Interior View of Valve

This fossil of Inoceramus (Volviceramus) grandis shows the larger size of some of the inoceramid clams from the Cretaceous (note penny for scale). Interior view of valve. Specimen from the Smoky Hill Chalk Member, Niobrara Chalk, Trego County.

Volviceramus fossil

Volviceramus — Exterior View of Valve

Exterior of fossil of Inoceramus (Volviceramus) grandis valve covered with fossils of encrusting oysters. Specimen from the Smoky Hill Chalk Member, Niobrara Chalk, Trego County.