This lower Pleistocene Bivalve has survived extinction and is today called the Southern Quahog. It belongs to the Family Veneridae and to the Genus and species Mercenaria campechiensis. Growth lines are continuous and the inner edge of the shall has fine, uniform crenulations. This was found by and is part of the collection of PMNS Curator T. W. Proctor, J.D. The quarter is to allow you to compare the size.