Multiple Specimen Mortality PlateThe 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