﻿Williams 
  — 
  Devonian 
  Interval 
  iri 
  northern 
  Arhansas. 
  147 
  

  

  Chonetes. 
  — 
  Two, 
  and 
  perhaps 
  three, 
  species 
  of 
  Chonetes 
  

   occur 
  in 
  these 
  shales. 
  

  

  C. 
  illinoisensis. 
  — 
  A 
  single 
  specimen 
  of 
  this 
  species 
  occurs 
  

   in 
  the 
  soft 
  green 
  shale 
  (1410 
  M2), 
  above 
  the 
  black, 
  at 
  Eureka 
  

   Springs. 
  It 
  is 
  smaller 
  and 
  more 
  delicate 
  than 
  the 
  typical 
  forms 
  

   of 
  the 
  species, 
  but 
  has 
  the 
  broad, 
  flat, 
  finely 
  striated 
  charac- 
  

   teristics 
  of 
  C 
  illinoisensis. 
  With 
  it 
  are 
  associated 
  many 
  

   smaller 
  forms, 
  which 
  may 
  be 
  of 
  two 
  or 
  one 
  species 
  ; 
  the 
  larger 
  

   number 
  are 
  about 
  the 
  size 
  and 
  shape 
  of 
  the 
  I^ew 
  York 
  C. 
  

   scitulus, 
  hut 
  varying 
  to 
  the 
  shape 
  of 
  Jconinckiamcs. 
  There 
  are 
  

   other 
  specimens 
  with 
  fewer 
  plications, 
  which 
  approach 
  the 
  

   character 
  of 
  Shnmard's. 
  0. 
  orriatiis. 
  It 
  is 
  altogether 
  probable 
  

   that 
  the 
  specimens 
  described 
  as 
  C. 
  ornatus^ 
  Shumard, 
  are 
  the 
  

   same 
  species 
  with 
  these. 
  There 
  is 
  considerable 
  range 
  of 
  varia- 
  

   tion 
  among 
  the 
  specimens 
  before 
  me, 
  and 
  it 
  seems 
  not 
  impos- 
  

   sible 
  that 
  they 
  all 
  may 
  represent 
  a 
  very 
  variable 
  species 
  ; 
  since 
  

   the 
  larger 
  forms 
  are 
  more 
  finely 
  striate 
  by 
  bifurcation 
  of 
  striae, 
  

   and 
  are 
  flat 
  and 
  frail, 
  as 
  in 
  the 
  largest 
  form 
  which 
  I 
  have 
  

   referred 
  to 
  C. 
  illinoisensis. 
  For 
  purposes 
  of 
  reference, 
  until 
  

   a 
  fuller 
  study 
  of 
  the 
  genus 
  is 
  made, 
  they 
  may 
  stand 
  as 
  C. 
  illi- 
  

   noisensis.^ 
  ornatus 
  and 
  ? 
  scitulus. 
  

  

  Productus. 
  — 
  One 
  fragmentary 
  specimen 
  from 
  the 
  green 
  

   shales 
  (1291) 
  (Y 
  204), 
  though 
  too 
  imperfect 
  to 
  specifically 
  iden- 
  

   tify, 
  is 
  distinctly 
  a 
  Carboniferous 
  type, 
  resembling 
  P. 
  hurling- 
  

   tonensis 
  Hall. 
  

  

  Productus 
  hallanus 
  AYalcott, 
  is 
  represented 
  by 
  several 
  

   specimens 
  from 
  the 
  green 
  shale 
  at 
  Eureka 
  Springs 
  (1410 
  M2), 
  

   and 
  from 
  the 
  black 
  shales 
  at 
  War 
  Eagle 
  Creek 
  (1279 
  Al). 
  

  

  The 
  genus 
  Rhynchonella 
  is 
  represented, 
  but 
  the 
  crushed 
  

   specimens 
  make 
  specific 
  identification 
  little 
  better 
  than 
  guess- 
  

   work. 
  Their 
  resemblance 
  to 
  similar 
  crushed 
  specimens, 
  in 
  the 
  

   Tennessee 
  greenish 
  shales 
  in 
  the 
  same 
  geological 
  position, 
  and 
  

   in 
  the 
  Waverly 
  of 
  Michigan 
  and 
  Ohio, 
  which 
  are 
  generally 
  

   referred 
  to 
  the 
  species 
  R. 
  sageriana 
  Winchell, 
  leads 
  me 
  to 
  so 
  

   label 
  them. 
  These 
  frail, 
  crushed 
  Rhynchonellas 
  are 
  from 
  the 
  

   Eureka 
  green 
  shales 
  (1410), 
  and 
  from 
  the 
  black 
  shales 
  at 
  War 
  

   Eagle 
  Creek 
  (1279). 
  P. 
  acuyninata 
  var,, 
  is 
  also 
  seen 
  in 
  the 
  

   green 
  shales 
  in 
  J^ewton 
  County 
  (1291). 
  

  

  Orthidw. 
  — 
  Of 
  this 
  family, 
  several 
  genera 
  are 
  represented. 
  

   Rhipidomella 
  (Oehlert) 
  is 
  represented 
  by 
  forms 
  which 
  are 
  

   generally 
  catalogued 
  under 
  the 
  name 
  Orthis 
  michelini 
  L'Eveille 
  ; 
  

   but, 
  though 
  crushed, 
  the 
  specimens 
  before 
  me 
  are 
  decidedly 
  

   broader 
  than 
  that 
  species, 
  and 
  thus 
  are 
  more 
  like 
  the 
  Devonian 
  

   types 
  of 
  O. 
  Vaniixemi 
  or 
  penelope. 
  In 
  outline, 
  they 
  are 
  close 
  

   to 
  that 
  of 
  0. 
  Oweni 
  Hall,* 
  but 
  have 
  no 
  trace 
  of 
  the 
  broad 
  fold 
  

  

  * 
  Paly. 
  X. 
  T., 
  vol. 
  viii, 
  Brachiopoda 
  T, 
  p. 
  342, 
  fig. 
  19 
  of 
  plate 
  vi. 
  

  

  