Cenozoic

The Cenozoic is the geological era extending from 65 million years ago to the present day; it includes the tertiary and quaternary periods. During this era, mammals spread over all the continents and in all environments. The Atlantic continued to open out. The Thetys ocean gradually shrank to finally disappear in the Alpine orogenesis. The climate became increasingly unstable and reached a paroxysm in the four great quaternary ice ages.