Givetian ICS Stage
                     (Tioughniogan, Taghanican, Geneseean)
 
                     From 391.8 +/- 2.7 To 385.3 +/- 2.6 Ma
 
  Start Defined By:  Conodont, lowest occurrence of Polygnathus hemiansatus, 
     near base of goniatite Maenioceras Stufe.
  End Defined By:  Conodont, lowest occurrence of Ancyrodella rotundiloba 
     (defines base of Lower Polygnathus asymmetricus conodont Zone).
 
  Start Based On:  Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
  End Based On:  Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
 
  Global Stratotype Section and Point:  Jebel Mech Irdane ridge, Tafilalt, 
     Morocco
 
 -- Overlaps With --
  Chinese Stage:        Yingtangian (397.5 - 391.4)
  North American Stage: Senecan     (388 - 370)
 
 -- A Substage of --
  Eon:    Phanerozoic     (542 - -5.5012e-005)
  Era:    Paleozoic       (542 - 251)
  Period: Devonian        (416 - 359.2)
  Epoch:  Middle Devonian (397.5 - 385.3)
 
 -- Preceeded By --
  ICS Stage:            Eifelian  (397.5 - 391.8)
  North American Stage: Ulsterian (416 - 391.8)
 
 -- Followed By --
  Epoch:     Late Devonian (385.3 - 359.2)
  ICS Stage: Frasnian      (385.3 - 374.5)
 
 -- Contains the Following Stages --
  Chinese Stage:        Dongganglingian (391.4 - 385.3)
  North American Stage: Erian           (391.8 - 388)
 
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