POWDER RIVER COUNTY
EAST SIDE ALONG POWDER RIVER DRAINAGE
24 KM SOUTH OF POWDERVILLE
HELL CREEK FORMATION
LANCIAN AGE
UPPER MAASTRICHTIAN STAGE
UPPERMOST SENONIAN SUBEPOCH
UPPER UPPER GULF EPOCH
LATE CRETACEOUS
STEM: TETRAPODA GOODRICH, 1930
SUPERCLASS: AMNIOTA HAECKEL, 1866
CLASS: REPTILIA LAURENTI, 1768
SUBCLASS: DIAPSIDA OSBORN, 1904
SUPERLEGION: NEODIAPSIDA BENTON, 1985
LEGION: ARCHOSAUROMORPHA HUENE, 1946
SUBLEGION: DINOSAUROMORPHA BENTON & NORMAN IN BENTON, 1985
INFRALEGION: DINOSAURIFORMES NOVAS, 1992
SUPERCOHORT: DINOSAURIA OWEN, 1842
COHORT: ORNITHISCHIFORMES COOPER, 1985
MAGNORDER: ORNITHISCHIA SEELEY, 1888
SUPERORDER: EURYOPDA SERENO, 1986
GRANDORDER: ARMATOSAURIA ZHAO, 1983 (emend)
ORDER: ANKYLOSAURIA OSBORN, 1923
SUBORDER: SCELIDOSAURIA COOPER, 1985
INFRAORDER: ANKYLOSAURA OSBORN, 1923
Family: ANKYLOSAURIDAE Brown, 1908
Subfamily: ANKYLOSAURINAE Brown, 1908
Ankylosaurus magniventris