Khuren Dukh Formation

The Khuren Dukh Formation, also known as the Khukhtyk Formation, Khukhteeg Formation, or Hühteeg Svita, (Хөхтээг формаци, Khökhteeg Formatsi), is a geological formation in Mongolia whose strata date back to the Aptian–Albian ages of the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.

Dinosaurs
The earliest record of Pachycephalosauria.