Green River Wyoming Cockerellites Fossil Fish Plate (Large
The Green River Formation of Colorado, Utah, and Wyoming is
one of the world's best locations for finding fossil fish. These Eocene
fossils were preserved in intermountain lake basins while the Rocky
Mountains were still growing! These fossils are over 50 million years
old. Cockerellites liops (formerly Prisca Cara liops) occurs in at
least one mass-mortality layer, indicating it was a schooling fish. It
closely resembles a modern sunfish.