The Beaufort Series is a geological formation forming part of the Karoo System and is rich in synapsid, or "proto-mammal" fossils. The Karoo System comprises, from oldest to youngest, Dwyka, Ecca, Beaufort and Stormberg Series. The name is derived from the district of Beaufort West. The formation reaches a thickness of 6-7 km and extends from the latter half of the Permian to the early Triassic. It is customarily divided into zones named after prevalent fossil types. From oldest to youngest these are: Tapinocephalus, Endothiodon, Cistecephalus, Lystrosaurus, Procolophon and Cynognathus.
The Beaufort Series covers the entire Karoo, Transkei, Pondoland, eastern Free State and western KwaZulu-Natal, while the overlying Stormberg Series covers the entire Lesotho and surrounding areas.