"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) †Early Devonian Epoch (419.2 - 393.3 Ma)
           1 (Stage) †Lochkovian Stage (419.2 - 410.8 Ma)
           2 (Stage) †Pragian Stage (410.8 - 407.6 Ma)
           3 (Stage) †Emsian Stage (407.6 - 393.3 Ma)