"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)
         1 (Epoch) †Early Devonian Epoch (419.2 - 393.3 Ma)
         2 (Epoch) †Mid Devonian Epoch (393.3 - 382.7 Ma)
         3 (Epoch) †Late Devonian Epoch (382.7 - 358.9 Ma)