SOUTH DAKOTA

CUSTER COUNTY

FAIRBURN

SECOND CALCARENITE FROM BASE

ORMAN LAKE MEMBER

GREENHORN FORMATION

DUNVEGANOCERAS PONDI ZONE

EARLY UPPER CENOMANIAN STAGE

UPPER MIDDLE GALLIC SUBEPOCH

LOWERMOST EARLY CRETACEOUS EPOCH

MIDDLE CRETACEOUS

STEM: TETRAPODA GOODRICH, 1930

SUPERCLASS: AMNIOTA HAECKEL, 1866

CLASS: REPTILIA LAURENTI, 1768

SUBCLASS: DIAPSIDA OSBORN, 1904

INFRACLASS: EURYAPSIDA COLBERT, 1945

SUPERORDER: SAUROPTERYGIA OWEN, 1860

GRANDORDER: EOSAUROPTERYGIA emend RIEPPEL, 1994

ORDER: PLESIOSAURIA OWEN, 1840 NON BLAINVILLE, 1835

SUBORDER: PLESIOSAURIA OWEN, 1840 NON BLAINVILLE, 1835

INFRAORDER: PLIOSAUROMORPHA NOVA

Superfamily: PLIOSAUROIDEA Seeley, 1874

Family: PLIOSAURIDAE Seeley, 1874

Polyptychodon interruptus