"global chronostratigraphic units"
   (Eon) Phanerozoic Eon (541.0 Ma - present)
     (Era) †Paleozoic Era (541.0 - 251.902 Ma)
       (Period) †Cambrian Period (541.0 - 485.4 Ma)
         (Epoch) †Caerfai Epoch
           1 (Stage) †Tommotian Stage
           2 (Stage) †Atdabanian Stage
           3 (Stage) †Lenian Stage