It is of an uncertain Early Cretaceous age, probably dating between the Berriasian and the Barremian.

It is the oldest unit of the 1,500 metres (4,900 ft) thick Sangar Series within the Vilyuy syneclise.

The mudstones, sandstones and shales of the formation were deposited in a fluvial to lacustrine environment.

The formation is best known for the Teete locality, which has revealed remains of numerous vertebrates, including dinosaurs and mammals.

Fossils recovered from the formation include:[1]