The Ergilian age is a period of geologic time (37.2—33.9 Ma) within the Late Eocene epoch of the Paleogene

Paleogene

The Paleogene is a geologic period and system that began 65.5 ± 0.3 and ended 23.03 ± 0.05 million years ago and comprises the first part of the Cenozoic Era...

 used more specifically with Asian Land Mammal Ages

Asian land mammal ages

The Asian Land Mammal Ages establishes a geologic timescale for prehistoric Asian fauna beginning 58.7 Mya during the Paleogene and continuing through to the Middle Pleistocene...

. It follows the Ulangochuian

Ulangochuian

The Ulangochuian age is a period of geologic time within the Late Eocene epoch of the Paleogene used more specifically with Asian Land Mammal Ages. It follows the Sharamurunian and precedes the Ergilian age....

 and precedes the Houldjinian

Houldjinian

The Houldjinian age is a period of geologic time within the Late Eocene epoch of the Paleogene used more specifically with Asian Land Mammal Ages. It follows the Ergilian and precedes the Kekeamuan age....

 age.

The Ergilian's lower boundary is the approximate base of the Priabonian

Priabonian

The Priabonian is, in the ICS's geologic timescale, the latest age or the upper stage of the Eocene epoch or series. It spans the time between and...

 age and approximate upper base of the Rupelian

Rupelian

The Rupelian is, in the geologic timescale, the older of two ages or the lower of two stages of the Oligocene epoch/series. It spans the time between and . It is preceded by the Priabonian stage and is followed by the Chattian stage....

 age. The Ergilian age is named after the Ergilian-Dzo fossil formations in Mongolia

Mongolia

Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...

.