Geologic Time Scale: Oligocene Epoch
(33.9 to 23 million years ago)
The Oligocene Epoch follows the Eocene Epoch and is followed by the Miocene Epoch of the Cenozoic Era. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich from his studies of marine beds in Belgium and Germany. The name comes from the Ancient Greek meaning “few” and “new”/”recent”, and refers to the sparsity of extant forms of mollusca.
The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the morn modern ecosystems of the Miocene. Major changes during the Oligocene included a global expansion of grasslands, and a regression of tropical broad leaf forest to the equatorial belt.