GOLDEN VALLEY COUNTY
FT. UNION GP.
SENTINEL BUTTE FORMATION
LATE PALEOCENE EPOCH
EARLY PALEOGENE
STEM: TETRAPODA GOODRICH, 1930
____________________________________________________________________________________SUPERCLASS: AMNIOTA HAECKEL, 1866
CLASS: REPTILIA LAURENTI, 1768
SUBCLASS: DIAPSIDA OSBORN, 1904
SUPERLEGION: NEODIAPSIDA BENTON, 1985
LEGION: ARCHOSAUROMORPHA HUENE, 1946
SUPERCOHORT CHORISTODERA NOVA
ORDER: CHORISTODERA COPE, 1876
Family: CHAMPSOSAURIDAE Cope, 1884
*Champsosaurus gigas