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)
       1 (Series) †Pliocene (5.333 - 2.58 Ma)
       2 (Series) †Miocene (23.03 - 5.333 Ma)