12-3/812.75x5/8" thick plate that contains a 9" long fossil specimen of Priscacara serrata, an extinct genus of perch from the Eocene (56 to 33.9 million years ago). Fossils of this fish are commonly found in the Green River Formation in Wyoming. Priscacara likely lived in freshwater streams and lakes, feeding on small creatures like snails, crabs, prawns, and tadpoles. The example we are offering is wonderfully preserved, w/individual vertebrae visible as well as well-defined tail and fins.