The Tertiary is a an out-of-date term for a geologic period 65 million to 1.8 million years ago. The Tertiary covered the time span between the superseded Secondary period and an out-of-date definition of the Quaternary period.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.