Locality: “Sandy Quarry”, near Buffalo, Harding County, South Dakota.
Horizon: Hell Creek Formation.
Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.
Note: 6 varieties of small ornithischians, based on caudal vertebrae.
Taxon with flattened hexagonal caudals.
Taxon with elevated hexagonal caudals.
Taxon with hexagonal caudals, ridge on dorsolateral prism.
Taxon with broad, elevated (but not vertical) caudal neural spines, transverse processes low and bladelike on centrum.
Taxon with square centrum, high transverse processes and Thesceolosaurus-like spines.
Taxon with transverse process and spine situated near the back of a “U” shaped