﻿492 
  W. 
  H. 
  TWELVETREES 
  ON 
  UPPER 
  PERMIAN 
  

  

  Schizodus 
  rossicus. 
  Feuestella 
  retiformis. 
  

  

  Cyatkocrinus 
  rauiosus. 
  Avicula 
  sericea. 
  

  

  Nautilus 
  Freieslebeni. 
  Stropkalosia 
  horrescens. 
  

  

  Olidophorus 
  Pallasi. 
  Murchisonia, 
  sp. 
  

  

  Avicula 
  speluncaria. 
  j 
  Area, 
  sp. 
  

  

  Spirifera 
  alata 
  ? 
  Terebratula 
  elongata. 
  

  

  Loxonerna, 
  sp. 
  Gervillia 
  ceratopliaga, 
  Schl. 
  

  

  Product-us 
  ? 
  I 
  

  

  A 
  thin 
  band 
  of 
  marl 
  lies 
  immediately 
  below 
  this 
  limestone 
  and 
  

   upon 
  barren 
  red 
  sandstone 
  of 
  the 
  Lower 
  Permian. 
  This 
  band 
  

   may 
  be 
  taken 
  as 
  the 
  equivalent 
  of 
  the 
  Kupferschiefer. 
  It 
  contains 
  

   a 
  few 
  fossils 
  undistinguishable 
  from 
  some 
  in 
  the 
  limestone, 
  viz. 
  

   Terebratula 
  elongata, 
  Schizodus 
  rossicus, 
  Clidopliorus 
  Pallasi, 
  Area, 
  

   and 
  a 
  few 
  obscure 
  vegetable 
  remains 
  ; 
  it 
  is 
  slightly 
  cupriferous. 
  

  

  The 
  limestone 
  again 
  appears 
  to 
  the 
  west 
  of 
  Orenburg. 
  The 
  Majak 
  

   quarries, 
  four 
  versts 
  N.W. 
  of 
  the 
  town, 
  show 
  it 
  dipping 
  at 
  a 
  gentle 
  

   angle, 
  and 
  appearing 
  to 
  pass 
  under 
  Orenburg, 
  which 
  would 
  then 
  be 
  

   on 
  Upper 
  Permian. 
  The 
  thick 
  terraces 
  of 
  red 
  sandstone 
  and 
  clay 
  

   exposed 
  on 
  the 
  high 
  bank 
  of 
  the 
  river 
  Ural, 
  upon 
  which 
  the 
  town 
  is 
  

   built, 
  are 
  unfossiliferous. 
  A- 
  boring 
  made 
  in 
  the 
  town 
  in 
  1841 
  

   registered 
  alternate 
  beds 
  of 
  red 
  and 
  grey 
  sandstones 
  and 
  red 
  clay 
  

   or 
  marl 
  to 
  a 
  depth 
  of 
  1366 
  feet. 
  It 
  is 
  difficult 
  to 
  explain 
  the 
  

   absence 
  of 
  the 
  Zechstein 
  limestone 
  in 
  this 
  boring 
  upon 
  any 
  other 
  

   hypothesis 
  than 
  that 
  of 
  its 
  inconstancy. 
  It 
  is 
  just 
  possible, 
  however, 
  

   that 
  the 
  whole 
  series 
  belongs 
  to 
  the 
  Lower 
  Permian. 
  

  

  Further 
  north 
  the 
  limestone 
  hills 
  appear 
  at 
  Bikoolova, 
  Kitayam, 
  

   &c. 
  At 
  Slonofka 
  and 
  Jemati 
  (near 
  Darghina) 
  its 
  bedding 
  is 
  nearly 
  

   horizontal. 
  It 
  runs 
  presumably 
  under 
  the 
  superincumbent 
  sands 
  

   as 
  far 
  west 
  as 
  Samara, 
  on 
  the 
  Volga, 
  where 
  it 
  forms 
  the 
  cliffs 
  of 
  

   that 
  river 
  and 
  of 
  the 
  Samara 
  stream. 
  From 
  these 
  cliffs 
  I 
  obtained 
  

   Loxonerna, 
  sp., 
  and 
  Pleurotomaria, 
  sp. 
  

  

  The 
  wide-spread 
  upper 
  sandstones 
  (fig. 
  2) 
  rest 
  in 
  apparent 
  con- 
  

   formhty 
  upon 
  the 
  Zechstein 
  limestone, 
  which 
  in 
  the 
  places 
  just 
  named, 
  

   and 
  at 
  other 
  spots 
  further 
  N.W., 
  is 
  revealed 
  by 
  upheaval 
  or 
  laid 
  bare 
  

   by 
  denudation. 
  Pig. 
  3 
  is 
  a 
  vertical 
  section, 
  taken 
  from 
  no 
  particular 
  

   spot, 
  but 
  typical 
  of 
  the 
  whole. 
  

  

  Although 
  the 
  reappearance 
  of 
  the 
  Zechstein 
  limestone 
  at 
  Samara 
  

   would 
  indicate 
  its 
  continuity 
  beneath 
  the 
  intermediate 
  part 
  of 
  the 
  

   basin, 
  yet 
  further 
  north 
  it 
  loses 
  its 
  monad 
  character, 
  and 
  alternates 
  

   with 
  marls, 
  which 
  are 
  variable 
  and 
  inconstant 
  on 
  the 
  same 
  horizon 
  

   and 
  in 
  the 
  same 
  district 
  ; 
  at 
  the 
  same 
  time 
  the 
  limestone 
  itself 
  

   assumes 
  a 
  less 
  calcareous 
  and 
  more 
  earthy 
  aspect. 
  Without 
  caution, 
  

   mistaken 
  opinions 
  may 
  be 
  formed 
  as 
  to 
  beds 
  being 
  above 
  or 
  below 
  

   the 
  limestone, 
  when 
  in 
  reality 
  they 
  may 
  be 
  intercalated 
  ; 
  but 
  at 
  

   Kargalinsk 
  there 
  is 
  more 
  uniformity 
  in 
  the 
  principal 
  divisions 
  of 
  

   the 
  system. 
  When 
  we 
  leave 
  the 
  limestone 
  behind 
  us 
  we 
  do 
  not 
  

   find 
  it 
  again. 
  

  

  The 
  preceding 
  remarks 
  are 
  not 
  intended 
  as 
  a 
  sketch 
  of 
  the 
  

   geology 
  of 
  the 
  country, 
  but 
  are 
  simply 
  such 
  preliminary 
  observations 
  

  

  