stratigraphic intervals
   (System) †Cretaceous (145.0 - 66.0 Ma)
     (Series) †Upper (100.5 - 66.0 Ma)
       (Subseries) †Senonian
         1 (Stage) †Maastrichtian (72.1 - 66.0 Ma)
         2 (Stage) †Campanian (83.6 - 72.1 Ma)
         3 (Stage) †Santonian (86.3 - 83.6 Ma)
         4 (Stage) †Coniacian (89.8 - 86.3 Ma)