Species: occidentalis LEIDY, 1856 (nomen dubium)
Etymology: Latin, occidentalis, "western."
= Hadrosaurus occidentalis (LEIDY, 1856) (nomen dubium)
= Trachodon occidentalis (LEIDY, 1856) KUHN, 1936 (nomen dubium)

Cotypes: USNM 219, 220, 221

Locality: Grand River, South Dakota.

Horizon: Lance Formation.

Biostratigraphy:

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

Material:

USNM 219: Posterior caudal vertebra (A).

USNM 220: Proximal median phalanx of pes (B).

USNM 221: Anterior caudal vertebra (C).

Referred material:

= Agathaumas milo COPE, 1874 (nomen dubium)
Etymology:
= Hadrosaurus milo (COPE, 1874) HAY, 1901 (nomen dubium)
= Agathaumus milo HAY, 1901 (sic)

Holotype: USNM 244537

Locality: Laramie beds, South Platte River, Colorado.

Horizon: Denver Formation.

Biostratigraphy:

Age: Lancian age, Late Maastrichtian Stage, Upper Senonian Subepoch, Upper Gulf Epoch, Late Cretaceous.

Material: Sacral centrum and a proximal end of tibia.