|   
                       White Rockian North American Stage
 
                          From 471.8 +/- 1.6 To 462 Ma
 
  Start Defined By:  Conodont, potentially lowest occurrence of Protoprioniodus 
     aranda or of Baltoniodus triangularis.
 
  Start Based On:  Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
 
 -- Overlaps With --
  ICS Stage:        Darriwilian (468.1 - 460.9)
  Australian Stage: Chewtonian  (473 - 471)
  General Stage:    Llandeilo   (464 - 460.9)
 
 -- A Substage of --
  Eon:    Phanerozoic       (542 - -5.5012e-005)
  Era:    Paleozoic         (542 - 251)
  Period: Ordovician        (488.3 - 443.7)
  Epoch:  Middle Ordovician (471.8 - 460.9)
 
 -- Preceeded By --
  Epoch:                Early Ordovician (488.3 - 471.8)
  ICS Stage:            Arenig           (478.6 - 471.8)
  Chinese Stage:        Dawanian         (472 - 471.8)
  European Stage:       Fennian          (473.5 - 471.8)
  North American Stage: Ibexian          (491 - 471.8)
  North American Stage: Cassinian        (473 - 471.8)
 
 -- Followed By --
  North American Stage: Mohawkian (462 - 451)
 
 -- Contains the Following Stages --
  ICS Stage:        Ordovician III (471.8 - 468.1)
  Australian Stage: Ypeenian       (470 - 468.1)
  Australian Stage: Castlemanian   (471 - 470)
  General Stage:    Llanvirn       (471.8 - 464)
 
 |