Chesapectin nefrens

Collected loose on the beach in St. Leonard, Maryland

middle Miocene

Choptank Formation

Drum Cliff Member

Chesapectin nefrens is an index fossil for the Drum Cliff Member of the Choptank Formation, meaning that whatever chunk of matrix one may find fallen out of the cliffs, the precise layer is known so that other fossils in the same block can be identified.

These are a very common find at St. Leonard and other places, but I particularly liked the coloration on this one!