stratigraphic intervals
   (System) †Cretaceous (145.0 - 66.0 Ma)
     (Series) †Lower (145.0 - 100.5 Ma)
       (Stage) †Albian (113.0 - 100.5 Ma)
         1 (Substage) †upper
         2 (Substage) †middle
         3 (Substage) †lower