An illustration of a Club-shell fossil from the Tertiary period. The Tertiary is a an out-of-date term for a geologic period 65 million to 1.8 million years ago. The Tertiary covered the time span between the superseded Secondary period and an out-of-date definition of the Quaternary period. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Tertiary extinction event, at start of the Cenozoic era, spanning to beginning of the most recent Ice Age, at the end of the Pliocene epoch.

Shell Fossil

An illustration of a Club-shell fossil from the Tertiary period. The Tertiary is a an out-of-date term…