﻿S. 
  Welter 
  — 
  Succession 
  of 
  Fossil 
  Faunas 
  in 
  Missouri. 
  187 
  

  

  scattered 
  through 
  the 
  limestone. 
  Its 
  geological 
  position 
  is 
  

   immediately 
  above 
  the 
  yellow 
  Chouteau 
  limestone, 
  and 
  in 
  some 
  

   places 
  it 
  even 
  seems 
  to 
  be 
  a 
  continuation 
  of 
  the 
  Chouteau, 
  

   with 
  no 
  sharply 
  fixed 
  dividing 
  line 
  ; 
  the 
  yellow, 
  sandy 
  Chouteau 
  

   gradually 
  changing 
  in 
  color 
  and 
  texture 
  till 
  it 
  becomes 
  this 
  

   hard 
  gray 
  limestone. 
  Also 
  the 
  two 
  faunas 
  are 
  blended 
  so 
  that 
  

   the 
  association 
  of 
  organic 
  forms 
  occurring 
  here, 
  is 
  transitional 
  

   between 
  the 
  Chouteau 
  and 
  the 
  true 
  Burlington. 
  The 
  zone 
  is 
  

   characterized 
  by 
  a 
  brachiopod 
  fauna. 
  

  

  At 
  Spout 
  Spring 
  (Station 
  21), 
  the 
  following 
  fauna 
  was 
  col- 
  

   lected 
  a 
  few 
  feet 
  above 
  the 
  yellow 
  Chouteau.* 
  

  

  *Spirifer 
  biplicatus 
  Hall. 
  

   ■\Productus 
  loevicostus 
  White. 
  

  

  Productus 
  sp. 
  

   *Terebratula 
  burlingtonensis 
  White. 
  

   \Spirifer 
  lineata 
  Martin. 
  

   j-Spirifer 
  suborbicularis 
  Hall. 
  

   \Chonetes 
  illinoisensis 
  Worthen. 
  

   \Orthis 
  swallovi 
  Hall. 
  ? 
  

  

  Spiriferina 
  sp. 
  

   *Phanerotinns 
  paradoxus 
  Winchell. 
  

   *Entolium 
  circulus 
  Shurnard. 
  

  

  Productus 
  punctatus 
  Martin. 
  

  

  Productus 
  burlingtonensis 
  Hall. 
  

  

  Terebratula 
  cf. 
  hastata 
  Sowerby. 
  

  

  Loxonema 
  sp. 
  

  

  The 
  most 
  abundant 
  species, 
  S. 
  biplicatus, 
  is 
  described 
  from 
  

   the 
  Kinderhook. 
  The 
  remaining 
  forms 
  are 
  partly 
  Chouteau 
  

   and 
  partly 
  Burlington. 
  The 
  species 
  which 
  range 
  downward 
  are 
  

   comparatively 
  rare. 
  

  

  Collections 
  have 
  also 
  been 
  made 
  from 
  this 
  zone 
  near 
  Pierson 
  

   Creek, 
  east 
  of 
  Springfield 
  (Station 
  17). 
  Here 
  the 
  fossils 
  are 
  

   from 
  an 
  horizon 
  higher 
  above 
  the 
  Chouteau 
  than 
  at 
  Spout 
  

   Spring, 
  but 
  the 
  lithological 
  characters 
  are 
  similar, 
  except 
  that 
  

   the 
  limestone 
  contains 
  much 
  more 
  chert. 
  The 
  following 
  

   species 
  were 
  collected 
  at 
  this 
  locality. 
  

  

  \Chonetes 
  illinoisensis 
  Worthen. 
  

   •f 
  Orthis 
  burlingtonensis 
  Hall. 
  

  

  Spiriferina 
  sp. 
  

   \Spirifer 
  suborbicularis 
  Hall. 
  

   *Spirifer 
  biplicatus 
  Hall. 
  

  

  "Spirifer 
  marionensis 
  Shumard, 
  

   \Spirifer 
  grimesi 
  Hall. 
  

   \Athyris 
  lamellosa 
  L'Eveille. 
  

  

  Phillipsis 
  sp. 
  

   \Derbyia 
  keokuk 
  Hall. 
  ? 
  

  

  The 
  fauna 
  differs 
  in 
  some 
  respects 
  from 
  the 
  Spout 
  Spring 
  

   fauna, 
  aud 
  more 
  nearly 
  resembles 
  the 
  true 
  Burlington. 
  

  

  At 
  an 
  exposure 
  on 
  Sac 
  Creek 
  (Station 
  20), 
  other 
  collections 
  

   were 
  made 
  which 
  may 
  be 
  referred 
  to 
  this 
  zone. 
  The 
  beds 
  are 
  

   of 
  an 
  higher 
  horizon 
  than 
  either 
  of 
  the 
  preceding 
  localities, 
  

   being 
  up 
  very 
  close 
  to 
  the 
  crinoidal 
  limestone 
  of 
  the 
  Burling- 
  

   ton 
  beds 
  proper. 
  In 
  this 
  fauna 
  species 
  of 
  higher 
  range 
  are 
  

   more 
  common 
  but 
  lower 
  forms 
  are 
  still 
  present. 
  The 
  fol- 
  

   lowing 
  species 
  were 
  collected. 
  

  

  * 
  Species 
  marked 
  * 
  are 
  forms 
  having 
  a 
  downward 
  range, 
  and 
  those 
  marked 
  \ 
  

   range 
  upward. 
  In 
  all 
  the 
  lists 
  the 
  species 
  are 
  arranged 
  according 
  to 
  their 
  rela- 
  

   tive 
  abundance, 
  the 
  most 
  abundant 
  being 
  placed 
  at 
  the 
  beginning 
  of 
  the 
  list. 
  

  

  