Of or of the geologic time, stone show, or sedimentary build up of 4th epoch of the Tertiary stage, described as the development of grasses and grazing mammals. See dining table at geologic time.
Of a geologic epoch inside the Neogene duration from about 23 to 5.3 million years ago; marked by the drift of continents for their present place.
Of or pertaining to the center division for the Tertiary.
How would you define Miocene?