Plate Measurements: ~8" long x 6" tall x 1/4" thick
Specimen Measurements: ~6-3/4" long
Location: Green River Formation, Wyoming
Time Period: Eocene ~50 Million Years Old
The Green River Formation in the USA covers an area over 25,000 square miles and is more than 2,000 feet thick. This formation, dates back more than 50 million years. It is one of the largest documented accumulations of sedimentary rock in the world. At the time, the area was sub-tropical and many different species flourished. Today, the majority of Fossil Fish taken out of this limestone formation are from two separate layers. "The 18" layer and the split fish layer". The 18" layer is composed of laminated sheets of limestone, allowing for fossil fish specimens to be extracted whole.
Diplomystus dentatus was one of those Green River fish and was related to today's herring. They were surface feeders, with their diet consisting of smaller fish, such as Knightia