﻿S. 
  Welle?' 
  — 
  Succession 
  of 
  Fossil 
  Faunas 
  in 
  Missouri. 
  193 
  

  

  Orthis 
  sivallovi 
  Hall. 
  

  

  Derbyia 
  keokuk 
  Hall. 
  

  

  Productus 
  sp. 
  

  

  Agaricocrinus 
  americanus 
  Eoemer. 
  

  

  Batocrinus 
  trochiscus 
  Meek 
  and 
  Wor- 
  

  

  then. 
  

   Spirifer 
  suborbicularis 
  Hall. 
  

  

  Spirifer 
  grimesi-logani 
  Hall. 
  

  

  Zaphrentis 
  varsoviensis 
  Worthen. 
  

  

  Athyris 
  incrassatus 
  Hall. 
  

  

  Zaphrentis 
  centralis 
  Worthen. 
  

  

  Chonetes 
  illinoisensis 
  Worthen. 
  

  

  Synbathocrinus 
  sivallovi 
  Hall. 
  

  

  Phillipsia 
  bufo 
  Meek 
  and 
  Worthen. 
  

  

  Spiriferina 
  sp. 
  Productus 
  setigerus 
  Hall. 
  

  

  Platyci 
  % 
  inus 
  saffoi*di 
  Troost. 
  I 
  Productus 
  pnnctatus 
  Martin. 
  

  

  Batocrinus 
  subtractus 
  White. 
  i 
  Dorycrinus 
  cornigerus 
  Hall. 
  

  

  Batocrinus 
  pyriformis 
  Shnrnard. 
  Actinocrinus 
  midtiradiatus 
  Shmnard. 
  

  

  Gi'anatocrinus 
  granulosus 
  Meek 
  and 
  Cyathocrinus 
  ioivensis 
  Owen 
  and 
  Shu- 
  

  

  Worthen. 
  mard. 
  

  

  Platyceras 
  equilatera 
  Hall. 
  | 
  Amplexus 
  fragilis 
  White 
  and 
  St. 
  John. 
  

  

  Athyris 
  lamellosa 
  L'Eveille. 
  I 
  Productus 
  burlingtonensis 
  Hall. 
  

  

  This 
  fauna 
  is 
  interesting 
  because 
  of 
  its 
  transitional 
  forms. 
  

   There 
  can 
  be 
  little 
  doubt 
  but 
  that 
  this 
  horizon 
  in 
  Southwest 
  

   Missouri 
  may 
  be 
  correlated 
  with 
  the 
  Burlington-Keokuk 
  

   transition 
  beds 
  in 
  Iowa. 
  The 
  fauna 
  contains 
  numerous 
  cri- 
  

   noids, 
  and 
  the 
  similarity 
  between 
  the 
  forms 
  collected 
  here, 
  and 
  

   those 
  described 
  by 
  Wachsmuth 
  and 
  Springer* 
  from 
  the 
  transi- 
  

   tion 
  beds 
  at 
  Burlington, 
  Iowa, 
  is 
  very 
  striking. 
  The 
  large 
  

   Spirifer 
  so 
  abundant 
  here 
  is 
  also 
  a 
  transitional 
  form. 
  It 
  is 
  the 
  

   representative 
  of 
  what 
  has 
  been 
  called 
  Spirifer 
  grimesi 
  in 
  the 
  

   Burlington 
  beds 
  below, 
  but 
  at 
  this 
  horizon 
  it 
  begins 
  to 
  lengthen 
  

   its 
  hinge 
  line 
  and 
  to 
  assume 
  the 
  characters 
  of 
  Spirifer 
  logani 
  

   of 
  the 
  succeeding 
  beds. 
  Here 
  however 
  the 
  grimesi 
  type 
  is 
  

   most 
  abundant, 
  the 
  individuals 
  with 
  elongated 
  hinge 
  lines 
  

   being 
  uncommon, 
  and 
  even 
  in 
  those 
  wmich 
  are 
  present 
  the 
  

   character 
  is 
  not 
  so 
  extremely 
  developed 
  as 
  it 
  is 
  higher 
  up. 
  

  

  Above 
  the 
  lower 
  beds 
  of 
  this 
  zone, 
  fossils 
  are 
  not 
  so 
  abun- 
  

   dant. 
  At 
  Station 
  5 
  the 
  following 
  species 
  were 
  collected. 
  

  

  Spirifer 
  grimesi-logani 
  Hall. 
  Platyceras 
  fisurella 
  Hall. 
  

   Phillipsia 
  bufo 
  Meek 
  and 
  Worthen. 
  Productus 
  punctatus 
  Martin. 
  

   Athyris 
  incrassatus 
  Hall. 
  ■ 
  Spirifer 
  pseudolineata 
  Hall. 
  

  

  Orthis 
  sivallovi 
  Hall. 
  Syringothyris 
  texta 
  Hall. 
  

  

  Productus 
  burlingtonensis 
  Hall. 
  Athyris 
  planosulcata 
  Phillips. 
  

  

  Spirifer 
  suborbicularis 
  Hall. 
  Palceacis 
  obtusus 
  Meek 
  and 
  Worthen. 
  

  

  Derbyia 
  keokuk 
  Hall. 
  Spirifer 
  sp. 
  

  

  Zaphrentis 
  centralis 
  Worthen. 
  Avicidopecten 
  magna 
  Swallow. 
  

  

  Zone 
  VII. 
  — 
  The 
  next 
  higher 
  horizon 
  studied, 
  having 
  a 
  

   distinct 
  fauna, 
  is 
  exposed 
  in 
  the 
  upper 
  part 
  of 
  the 
  quarry 
  at 
  

   Station 
  7. 
  The 
  bed 
  is 
  largely 
  composed 
  of 
  chert, 
  and 
  may 
  be 
  

   designated 
  as 
  the 
  upper 
  chert 
  bed. 
  The 
  chert 
  here 
  is 
  very 
  

   different 
  from 
  that 
  in 
  Zone 
  V. 
  It 
  is 
  very 
  hard 
  and 
  brittle 
  and 
  

   much 
  stained 
  with 
  iron, 
  and 
  occurs 
  in 
  much 
  larger 
  and 
  more 
  

   irregular 
  masses 
  than 
  in 
  the 
  lower 
  bed. 
  Both 
  the 
  chert 
  and 
  

   the 
  limestone 
  abound 
  in 
  fossils, 
  but 
  in 
  all 
  cases 
  the 
  calcareous 
  

   matter 
  of 
  the 
  fossils 
  contained 
  in 
  the 
  chert 
  has 
  been 
  dissolved 
  

   out, 
  leaving 
  the 
  fossils 
  in 
  the 
  form 
  of 
  moulds. 
  In 
  these 
  impres- 
  

  

  * 
  Proc. 
  Phil. 
  Acad. 
  Nat. 
  Sci., 
  1878, 
  p. 
  224. 
  

  

  