Huajiying Formation

The Huajiying Formation is a geological formation in Hebei, People's Republic of China. Known for its fossils including primitive birds, the age of the formation is uncertain. It may represent an early portion of the Jehol Biota, dating to somewhere in the early Cretaceous or late Jurassic periods. It may correlate with the early Cretaceous Dadianzi Formation and parts of the Yixian Formation, with an age range between 140 and 122 Ma ago. It contains the Qiaotou Member, sometimes treated as a distinct formation.

Huajiying Formation

The Huajiying Formation is a geological formation in Hebei, People's Republic of China. Known for its fossils including primitive birds, the age of the formation is uncertain. It may represent an early portion of the Jehol Biota, dating to somewhere in the early Cretaceous or late Jurassic periods. It may correlate with the early Cretaceous Dadianzi Formation and parts of the Yixian Formation, with an age range between 140 and 122 Ma ago. It contains the Qiaotou Member, sometimes treated as a distinct formation.