The Ulansuhai Formation is a geological formation in Inner Mongolia, north China. Dinosaur remains are among the fossils that have been recovered from the formation. The Ulansuhai Formation has traditionally been considered to date to the Aptian-Albian stages of the Lower Cretaceous, due to similarities between the Ulansuhai fauna and known Aptian formations. However, radiometric dating done on underlying formations has shown this to be incorrect. Due to the age of underlying rocks, the Ulansuhai Formation cannot be older than the Turonian stage of the Late Cretaceous, about 92 Ma.

Fossil content

Dinosaurs

The carcharodontosaurid Shaochilong and ankylosaurid Gobisaurus were initially reported from this formation, but actually derive from the Miaogou Formation, which has outcrops nearby.

Testudines

Ostracods