The Marnes d’Auzas Formation (Auzas Marls Formation) is a geological Formation in southwestern France (departments of Ariège and Haute-Garonne) whose strata date back to the Late Maastrichtian. It is about 100 metres thick and consists primarily of marls with some interbeds of sandstones. It corresponds to sediments whose depositional environment evolved from the paralic domain (coastal lagoons, tidal marsh, tidal muddy channel) at the base of the formation, towards a more continental domain (alluvial plain, fluvial channels) in its upper part. The Marnes d’Auzas Formation was deposited in the west coast of the former Ibero-Armorican Island, which included much of France and Spain.

Vertebrate paleofauna