﻿D. 
  K. 
  Greger 
  — 
  Devonian 
  of 
  Central 
  Missouri. 
  265 
  

  

  Aet. 
  XIX. 
  — 
  The 
  Devonian 
  of 
  Central 
  Missouri 
  (II) 
  ; 
  by 
  

   Daeling 
  K. 
  Geegee. 
  

  

  In 
  the 
  type 
  locality 
  of 
  the 
  Craghead 
  Creek 
  shale, 
  sec- 
  

   tion 
  17, 
  township 
  46, 
  range 
  9 
  west, 
  Callaway 
  county, 
  the 
  

   youngest 
  member 
  of 
  the 
  section 
  is 
  a 
  light-colored, 
  sandy 
  

   shale, 
  carrying 
  an 
  abundant 
  series 
  of 
  pelecypods, 
  few 
  

   corals 
  and 
  bryozoa, 
  with 
  an 
  association 
  of 
  brachiopods, 
  

   never 
  abundant, 
  of 
  the 
  following 
  species 
  : 
  Productella 
  

   callaway 
  ensis, 
  Schizophoria 
  striatula 
  (a 
  large 
  variety), 
  

   Spirifer 
  iow 
  ensis, 
  Cyrtina 
  triquetra, 
  Atrypa 
  reticularis 
  

   (with 
  coarse 
  ribs 
  and 
  extravagantly 
  developed 
  growth 
  

   varices). 
  The 
  pelecypods, 
  which 
  for 
  the 
  most 
  part 
  are 
  

   undescribed 
  forms, 
  comprise 
  the 
  following 
  genera 
  : 
  Palce- 
  

   oneilo, 
  Edmondia, 
  Actinopteria, 
  Grammysia, 
  Schizodus, 
  

   Pterinopecten, 
  Paracyclas, 
  and 
  Goniophora. 
  

  

  The 
  Cow 
  Creek 
  Section 
  of 
  the 
  Craghead 
  Creek 
  Shale. 
  

  

  About 
  fifteen 
  miles 
  northeast 
  of 
  this 
  former 
  locality, 
  

   in 
  section 
  25, 
  township 
  47, 
  range 
  8 
  west, 
  on 
  the 
  divide 
  

   between 
  Auxvasse 
  and 
  Loutre 
  rivers, 
  a 
  small, 
  sharp 
  

   anticline, 
  cut 
  almost 
  at 
  right 
  angles 
  by 
  Cow 
  Creek, 
  gives 
  

   a 
  fine 
  exposure 
  of 
  Craghead 
  Creek 
  shale, 
  .which 
  for 
  the 
  

   most 
  part 
  is 
  made 
  up 
  of 
  beds 
  younger 
  than 
  those 
  exposed 
  

   in 
  the 
  type 
  locality. 
  The 
  thickness 
  of 
  the 
  Devonian 
  ex- 
  

   posed 
  in 
  this 
  locality 
  is 
  somewhat 
  over 
  twenty 
  feet 
  ; 
  the 
  

   section, 
  measured 
  from 
  the 
  top 
  to 
  the 
  creek 
  bed, 
  is 
  as 
  

   follows 
  : 
  

  

  Zone 
  No. 
  1. 
  A 
  fine-grained, 
  chocolate-colored, 
  paper 
  shale, 
  never 
  

   abundantly 
  fossiliferous 
  and 
  frequently 
  quite 
  fer- 
  

   ruginous 
  ; 
  the 
  known 
  fossils 
  from 
  this 
  zone 
  are 
  spe- 
  

   cies 
  common 
  to 
  the 
  shales 
  below 
  and 
  comprise 
  the 
  

   following 
  forms 
  : 
  Athyris 
  minima 
  Swallow, 
  Spirifer 
  

   amarus 
  Swallow, 
  Lioclema 
  occidens 
  H. 
  & 
  W., 
  Clado- 
  

   pora 
  prolifica 
  H. 
  & 
  W., 
  and 
  large 
  masses 
  of 
  Stroma- 
  

   top 
  or 
  a. 
  

  

  Thickness 
  0-36 
  inches. 
  

  

  Zone 
  No. 
  2. 
  Hard 
  limy 
  shale, 
  gray 
  in 
  color, 
  fossils 
  frequently 
  

   silicified, 
  crushed 
  and 
  water- 
  worn; 
  Stropheodonta 
  

   callaway 
  ensis 
  Swallow 
  (common), 
  Productella 
  cal- 
  

   laway 
  ensis 
  Swallow 
  (common), 
  Spirifer 
  euruteines 
  

   Owen 
  (rare), 
  Cyrtina 
  triquetra 
  Hall 
  (rare), 
  Schi- 
  

   zophoria 
  striatula 
  %ow 
  ensis 
  (rare), 
  Zaphrentis 
  sp. 
  

   (common), 
  two 
  species 
  of 
  Aulopora 
  (rare). 
  

  

  Thickness 
  12 
  inches. 
  

  

  Zone 
  No. 
  3. 
  Yellow-brown, 
  sandy 
  shale, 
  almost 
  barren 
  of 
  fossils 
  ; 
  

   pelecypods, 
  two 
  species 
  (rare), 
  gastropods, 
  casts 
  of 
  

  

  