Another group of pictures from my folder clean up feature this Chesapecten nefrens pelecypod from the Calvert formation of Maryland. I collected this 25 years ago while on a trip to Calvert Cliffs in Maryland. It was found in the Choptank formation while staying at Matoaka Cottages.
Interior of both valves. The white paint and ink lettering were a short lived attempt by my younger self to catalog my fossil collection at the time. In this case the "CC" stood for Calvert Cliffs and the number indicates that this was the first numbered specimen (but not necessarily the first specimen I found).
The Choptank formation dates to the Miocene epoch (Langhian to Serravallian stages) of the Neogene period.