System |
Series |
Stage |
Western
Interior US Biozone |
Cretaceous |
Upper Cretaceous | Maastrichtian |
|
Campanian (part) |
Scaphites
hippocrepis I-III |
||
Scaphites
leei III |
|||
Santonian |
Desmoscaphites
bassleri |
||
Desmoscaphites erdmanni |
|||
Clioscaphites choteauensis |
|||
Clioscaphites
vermiformis |
|||
Clioscaphites
saxitonianus |
|||
Coniacian | Scaphites depressus |
||
Scaphites
ventricosus |
|||
Forresteria alluaudi |
|||
Forresteria
peruana |
|||
Turonian |
Prionocyclus
germari |
||
Prionocyclus
quadratus |
|||
Prionocyclus
novimexicanus |
|||
Prionocyclus wyomingensis | |||
Prionocyclus macombi |
|||
Prionocyclus hyatti |
|||
Collignoniceras
praecox |
|||
Collignoniceras woollgari |
|||
Mammites
nodosoides |
|||
Vascoceras
birchbyi |
|||
Pseudaspidoceras
flexuosum |
|||
Watinoceras
devonense |
|||
Cenomanian (part) |
Nigericeras
scotti |
||
Neocardioceras
juddii |
|||
Burroceras
clydense |
|||
Euomphaloceras
septemseriatum |
|||
Vascoceras
diartianum |
|||
Dunveganoceras
conditum |
|||
Dunveganoceras
albertense |
|||
Lower
Cretaceous |