Fossil Fish Knightia

A fossil fish Knightia sp. about 55 million years old from the Green River Formation, Wyoming, U.S.A. Knightia were Herring like fish living in large shoals in freshwater lakes. The Wyoming lakes were regularly subjected to some local events which killed  the fish in large numbers and provided the right conditions for their preservation. The limestone containing the fossil naturally splits into thin plates, revealing the fish inside. The fish measures about 85mm from lip to fin tip.