Oligocene

Part of speech: noun

Definitions

1. A geological epoch within the Cenozoic Era known for distinct fossil records and climate changes that influenced animal and plant life
2. The earlier segment of the Cenozoic Era defined by unique rock layers and the evolution of mammals into modern forms and ecosystems
3. A division of geological time in the Paleogene Period marked by significant climatic shifts and mammal diversification

Etymology: The name "Oligocene" was coined in 1854 by the German palaeontologist Heinrich Ernst Beyrich, who needed a label for a set of rock layers in northern Germany that held relatively few fossils of living species compared with the younger strata above them. The Greek "oligos" means "few" or "little," and "kainos" means "new" or "recent," the same root that gives the Miocene and Pliocene their names. Beyrich's term was built from "oligo-" plus "-cene," so it literally means "few-recent" or "little-new." The name is a little misleading, and that is part of its story. Most of the Oligocene strata that Beyrich named contained fewer modern-looking species than the epochs after them, which is why "few" was the feature that stood out. The label was not meant to describe the epoch's general character, and the time span it later came to cover was defined around those German rock sequences.