Invertebrate Fossils OF NJ

Exogyra sp. (Say)

   The oysters Exogyra and Pycnodonte were the most common bivalves of the Cretaceous period. Lying on the seabed floor with the convex side in the mud and the flat side position at the seafloor surface for camouflage. Exogyra first appeared in the lower Cretaceous and had disappeared by the upper Cretaceous. These fossil remains can be found in abundance at numerous locations in Monmouth County.
Five species of Exogyra that have been reported from New Jersey;

Exogyra cancellata (Stephenson)
Exogyra costata (Say)
Exogyra erraticostata (Stephenson)
Exogyra spinifera (Stephenson)
Exogyra ponderosa (Roemer)
 

Exogyra costata from Monmouth County, NJ

 

Characteristic spiral coil of Exogyra.
 

Exogyra sp. in real life position.
 

Exogyra spinifera at over 5 inches across.
This shell is over 1 inch thick in places.
Monmouth County, NJ.
 

Upper valve from an unknown species.