These 50 million year old, Eocene-Era fossil fish come from one of the world's famous Laggerstatten, the Green River Formation in Wyoming. These particular fish are Knightia eocaena, the State Fossil of Wyoming. In FossilLake, these fish reach their maximum size of 25 cm. This fossil measures approximately 1-7/8in. Knightia was a schooling fish that is sometimes found in mass mortality layers confined to a single plane. A plastic easel display stand is included.