Placopecten clintonius pelecypod from the Yorktown formation of Virginia

This shell was among a number of Chesapectin jeffersonius specimens and it caught my eye due to the difference. A little research leads me to believe that this is a Placopecten clintonius pelecypod as it exists within the Yorktown formation at the same horizon as C. jeffersonius. The shell is smaller than C. jeffersonius and the radial ribs are both more numerous and finer.

This specimen came from the Yorktown Formation, which is Neogene in age (Pliocene epoch, Zanclean stage), along the James River in Virginia.

Chesapectin jeffersonius pelecypod from the Yorktown formation of Virginia

I acquired this shell at a rock/fossil/mineral show this past spring from someone who collected it themselves. It's a Chesapectin jeffersonius pelecypod from the Yorktown formation (Neogene, Pliocene epoch, Zanclean stage) of Virginia and was found along the James River.  The shell is enormous and I can just imagine what the scallops would have tasted like! It's only a single valve, I'm not sure if it is the left or the right but was a host to some epibionts. There are large barnacles (Balanus concavus), barnacles spats and some corals (Septastrea marylandica). All in all it's a terrific specimen that gives evidence of the environment that it lived in.

Shell exterior

Shell interior

I think these small holes are the traces from the boring sponge Cliona sp.

A better view of the huge barnacles

and some shots of the corals.

Corals with Cliona sp. boring sponge traces