stratigraphic intervals
   (System) †Jurassic (201.3 - 145.0 Ma)
     (Series) †Upper (163.5 - 145.0 Ma)
       1 (Stage) †Tithonian (152.1 - 145.0 Ma)
       2 (Stage) †Kimmeridgian (157.3 - 152.1 Ma)
       3 (Stage) †Oxfordian (163.5 - 157.3 Ma)