Oligocene
Geologic period
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The Oligocene is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present. As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates... Wikipedia
Period: Paleogene
Occurred: 33.9 million years ago - 23.03 million years ago
Chronological unit: Epoch
Lower boundary definition: LAD of Planktonic Foraminifers Hantkenina and Cribrohantkenina
Lower boundary GSSP: Massignano quarry section, Massignano, Ancona, Italy; 43°31′58″N 13°36′04″E / 43.5328°N 13.6011°E
Organisms: Pilchenia, Ilex mormonica, Quercus shangcunensis, and more
Oligocene Birds
