Examples from the Web for oligocene
It is these latter forms which come nearest to modern Carnivora, most of them being of Oligocene age.
The genus Mesohippus, of the middle Oligocene, may be selected as a kind of half-way stage in the long progression.Darwin and Modern Science|A.C. Seward and Others
The genus began in the Oligocene and continued down to the Pliocene.The Cambridge Natural History, Vol X., Mammalia|Frank Evers Beddard
Its fauna is incompletely known; probably it is of Miocene or Oligocene origin.
Both lineages likely had an earlier history extending back to their divergence in the Oligocene.
British Dictionary definitions for oligocene
Word Origin for Oligocene
Word Origin and History for oligocene
1856, "pertaining to the Tertiary period between the Eocene and the Miocene," coined in German (1854) by Heinrich Ernst von Beyrich, from oligo- "small, little, few" + -cene. So called because few modern fossils were found in Oligocene rocks.