Species: agilis (MARSH, 1872) MARSH, 1890
Etymology: Latin, agilis, "agile, nimble."
= Hadrosaurus agilis MARSH, 1872
= Trachodon agilis (MARSH, 1872) KUHN, 1936

Holotype: YPM 1190

Locality: Near Smokey Hill River, SE. 29 or 29, T13S, R34W, 26 m E of Fort Wallace, Logan County, Kansas.

Horizon: Smoky Hill Chalk Member, Niobrara Formation.

Biostratigraphy:

Age: Santonian or Campanian Stage, Senonian Subepoch, Gulf Epoch, Late Cretaceous.

Material: Parts of maxillae and dentary, the vertebreal column practically complete, right scapula, both sternals, both humeri, both radii and ulnae, right ilium, both femora, 1 fibula and both feet.
Note: BROWN, 1907 reports 3 gastroliths found near the front legs, but he may be referring to an Edmontosaurus sp skeleton and not this specimen.