from 25 million to 13 million years ago; appearance of grazing mammals

An epoch of the early Tertiary period, found in-between the Oligocene and the Pliocene eras.

The period of geologic time between 5 and 24 million years before the present, when Columbia River basalt* was extruded into the Pasco Basin.

The period of geologic time that extends from 24 million years to 5 million years before the present.

The Miocene epoch was a geologic time span that lasted from 24 million to 5 million years ago. During the Miocene, modern birds and many mammals evolved (including the horses, dogs, bears, South American monkeys, and apes in southern Europe). Ramapithecus appeared; this primate was pehaps an ancestor of man. The climate was relatively warm (as compared to the earlier Oligocene or the later Pliocene). There were extensive grasslands (and grasses diversified), and the interior of the continents were relatively dry; northern coniferous forests expanded. Kelp forests appeared in the seas. In North America, the Sierra Nevada Mountains and the Cascade Mountains were formed; in the South America, the Andes Mountains arose. The Bering land bridge formed during the Miocene, connecting Russia and Alaska, allowing many animals to migrat across continents. The Isthmus of Panama also formed during this time. Australia became very dry (but went through wet and dry periods). In Europe, the Mediterranean Sea and Indian Ocean were separated (they had been connected by the Tethys Sea).