| 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 |
|||