Oligocene

Ol·i·go·cene  (l-g-sn, l-)

adj.

Of or belonging to the geologic time, rock series, or sedimentary deposits of the third epoch of the Tertiary Period, characterized by futher development of modern mammalian fauna, including the rise of the true carnivores and their gradual replacement of the creodonts. See Table at geologic time.

n.

The Oligocene Epoch or its system of deposits.

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Oligocene [ol-lig-go-seen]

Adjective

Geol of the epoch of geological time about 35 million years ago [Greek oligos little + kainos new]

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Oligocene  (l-g-sn)

The third epoch of the Tertiary Period, from about 37 to 24 million years ago. During this time there was an increase in volcanic activity, and Australia and South America separated from Antarctica. The climate started to cool and a glacier started to form in Antarctica. Modern mammalian groups continued to develop, and the first cats, dogs, horses, and related mammals appeared. Artiodactyls (even-toed ungulates) took over from the perissodactyls (uneven-toed ungulates) as the dominant medium-sized herbivores. Many types of grass also first appeared at this time. See Chart at geologic time.

Thesaurus

Noun

1.

Oligocene - from 40 million to 25 million years ago; appearance of sabertoothed cats Oligocene epoch Tertiary, Tertiary period - from 63 million to 2 million years ago