Fossil Fish Pair (Knightia & Diplomystus) - Wyoming

This is a pair of fossil fish from the Green River Formation of Wyoming. The larger of the two fish is a 4.3" long Knightia eocaena and the smaller one is a Diplomystus dentatus. They are both presented on a solid, rectangularly cut piece of shale.

About Fossil Lake

50 million years ago, in the Eocene epoch, these fish thrived in Fossil Lake, which was fed by the Uinta and Rocky Mountain highlands. The anoxic conditions at the bottom of Fossil Lake slowed bacterial decomposition, prevented scavengers from disturbing corpses, and, most interestingly, suffocated creatures that ventured into the oxygen-starved aquatic layer. The result is a miraculous exhibition of Eocene biota: a subtropical aquatic community within sycamore forests, teeming with creatures such as freshwater stingrays, dog-sized horses, menacing alligators, early flying bats, and one of the first primates.

A view of one of the commercial quarries where fossils from the Green River Formation are collected.