The Paleogene (also spelled Palaeogene or Palæogene; informally Lower Tertiary) is a geologic period that began 66 and ended 23.03 million years ago and comprises the first part of the Cenozoic Era.
Eocene 1
noundomain: time
Princeton WordNet [ver.3.1]
English
Definition
from 58 million to 40 million years ago; presence of modern mammals
The Paleogene (also spelled Palaeogene or Palæogene; informally Lower Tertiary) is a geologic period that began 66 and ended 23.03 million years ago and comprises the first part of the Cenozoic Era.