Animonoid, conodont, fusulinid, ostracod and radiolarian
  biozonations and their assumed mutual correlations are presented
  in five figures.  The Standard, Tethyan and Russian (Cis-Urals,
  Russian Platforrn) stages and their mutual correlation are shown.
  The numerical age of most of the stage boundaries in the Permian
  must be interpolated from the few reliable radiometric dates (inter-
  polated numerical ages are shown in italics) using such data as the
  thickness of Panthalassa radiolarites with assumed uniform depo-
  sitional rate in the different stages, number of comparable biozones
  of different biozonations within one stage, evaluation of
  Milankovitch cyclicity.  Few radiometric data are known from the
  Permian (indicated in normal numbers).
       Zonations throughout the Permian exist for ammonoids, con-
  odonts, fusulinids and radiolarians, but the uppermost Permian
  Pleuronodoceras occidentale und Hypophiceras changxingense
  ammonoid zones just below the boundary clay up to the Permian-
  Triassic boundary have not yielded any fusulinids and radiolar-
  ians.  An ostracod zonation on the base of phylomorphogenetic
  lineages is only known for the Tethyan Upper Permian (Kozur,
  1985).  Ostracod zonations for the Cis-Uralian Lower Permian, es-
  pecially for the Kungurian, are mainly based on facies-related fau-
  nistic changes of smooth bairdiids and other predominantly smooth
  facies dependent forms, and have therefore only a restricted re-
  gional importance in the Cis-Uralian area. lt is not clear whether
  the zones are synchronous throughout the Cis-Urals without in-
  dependent stratigraphic control.  Therefore, these zones are not
  shown.