"global chronostratigraphic units"
   (Eon) Phanerozoic Eon (541.0 Ma - present)
     (Era) †Paleozoic Era (541.0 - 251.902 Ma)
       (Period) †Devonian Period (419.2 - 358.9 Ma)
         (Epoch) †Mid Devonian Epoch (393.3 - 382.7 Ma)
           1 (Stage) †Eifelian Stage (393.3 - 387.7 Ma)
           2 (Stage) †Givetian Stage (387.7 - 382.7 Ma)