This is a exquisitely preserved fossil “sand dollar” of the species Encope tamiamiensis. It comes from the Tamiami Formation of Southern Florida. This formation dates to the late Miocene through Pliocene periods. The fossil has been completely removed from the surrounding, limestone matrix.
The “sand Dollars” are flattened Sea Urchins. They are Echinoderms related to starfish and modern sea urchins. They lived in shallow water environments and lagoons below the tide line buried in the sand or mud. When alive they were covered by spines. They are basically circular in shape and various species could be very thick. This species is on the thin side only several millimeters thick.
They fed on algae and diatoms and small copepods living at the bottom of the shallow water beach areas.
You will receive one similar to the ones pictured. We will choose the best of the lot to send your way. They average 1 1/4 to 1 1/2 long.