stratigraphic intervals
   (System) †Tertiary (66.0 - 2.58 Ma)
     (Subsystem) †Neogene (23.03 - 2.58 Ma) see System Neogene System (23.03 - 2.58 Ma)
       (Series) †Miocene (23.03 - 5.333 Ma)
         (Subseries) †Middle
           (Stage) †Serravallian (13.82 - 11.63 Ma)