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                         Mayan Russian-Kazakhian Stage
                                   (Menevian)
 
                            From 502 To 501 +/- 2 Ma
 
  End Defined By:  Trilobite, lowest occurrence of agnostoid Glyptagnostus 
     reticulatus.  Coincides with base of large positive carbon-isotope 
     excursion.
 
  End Based On:  Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
 
 -- A Substage of --
  Eon:                  Phanerozoic     (542 - -5.5012e-005)
  Era:                  Paleozoic       (542 - 251)
  Period:               Cambrian        (542 - 488.3)
  Epoch:                Middle Cambrian (513 - 501)
  Australian Stage:     Boomerangian    (504 - 501)
  Chinese Stage:        Zhungxian       (505 - 501)
  North American Stage: Marjuman        (504 - 494.5)
 
 -- Preceeded By --
  Russian-Kazakhian Stage: Amgan (513 - 502)
 
 -- Followed By --
  Epoch:                   Late Cambrian (501 - 488.3)
  ICS Stage:               Paibian       (501 - 496)
  Australian Stage:        Mindyallan    (501 - 497)
  Regional Stage:          Maentwrogian  (501 - 496.8)
  Russian-Kazakhian Stage: Ayusokkanian  (501 - 494.5)
 
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