Genus: Purgatorius VAN VALEN & SLOAN, 1965
Etymology: In reference to Purgatory Hill, McCone County, Montana.

Species: ceratops VAN VALEN & SLOAN, 1965
Etymology: Greek, ceratops, "horned face."

Holotype: UM VP1547

Locality: Harbicht Hill local fauna, McCone County, Montana.

Horizon: Hell Creek Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material: Right M2.