from The American Heritage® Dictionary of the English Language, 4th Edition
- 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.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Of a geologic epoch within the Paleogene period from about 34 to 23 million years ago; marked by the rapid evolution in a warm climate.
- proper n. The Oligocene epoch.
from the GNU version of the Collaborative International Dictionary of English
- adj. Of, pertaining to, or designating, certain strata which occupy an intermediate position between the Eocene and Miocene periods.
from The Century Dictionary and Cyclopedia
- In geology, a division of the Tertiary series, including groups formerly classed in part as Upper Eocene and in part as Lower Miocene.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. from 40 million to 25 million years ago; appearance of sabertoothed cats
This differs chiefly from Lyell's classification in the introduction of the term Oligocene for the upper part of the original Eocene, which was somewhat unwieldy.
The oldest of these formations dated from the geological time period known as the Oligocene, making them roughly thirty million years old.
But still later he repeats the assertion of the Eocene ( "Oligocene") age of the Santo Domingo beds in sueh a categorical manner as to demand an equally pointed refutation,! the more especially since Mr. Conrad is the oldest and best infonned of the authorities on the American Tertiaries.
Even the ants and bees have made no advance since the Oligocene.
The fine sandy and silty loams are formed from weathered Oligocene and Miocene sandstone (Ogallala and Arikaree Formations, and upper White River Groups).
More specifically, there are Triassic, Jurassic, Cretaceous, Eocene, and Miocene marine and Oligocene and Plio-Pleistocene nonmarine sedimentary rocks.
More specifically, there are Cretaceous, Eocene, Miocene, and Pliocene marine and Oligocene and Plio-Pleistocene nonmarine sedimentary rocks.
The Tertiary sedimentary rocks are Eocene, Oligocene, Miocene, and Pliocene.
Riversleigh's late Oligocene to early and middle Miocene (possibly 25-12 my) assemblages have been interpreted by Archer et al. (1989) and Archer et al., (1991) to represent rainforest communities.
It is underlain by Miocene, Oligocene, Eocene, and Paleocene sediments.
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