﻿K. 
  F. 
  Mather 
  — 
  Pottsville 
  Formations 
  and 
  Faunas. 
  135 
  

  

  The 
  complete 
  faunal 
  list 
  is 
  as 
  follows 
  : 
  — 
  

  

  Pentremites 
  angustus 
  Hambach 
  

  

  Cromyocrinus 
  n. 
  sp. 
  

  

  Archeocidaris 
  sp. 
  

  

  Rhombopora 
  lepidodendroides 
  Meek 
  

  

  Cystodictya 
  sp. 
  

  

  Rhipidomella 
  pecosi 
  (Marcou) 
  

  

  Productus 
  nanus 
  Meek 
  and 
  Worthen 
  ? 
  

  

  Productus 
  morrowensis 
  Mather 
  ? 
  

  

  Spirifer 
  opimus 
  Hall 
  

  

  Spirifer 
  goreii 
  Mather 
  

  

  Squamularia 
  perplexa 
  (McChesney) 
  

  

  Spiriferina 
  transversa 
  (McChesney) 
  

  

  Composita 
  ozarkana 
  Mather 
  

  

  Composita 
  gibbosa 
  Mather 
  

  

  Nucula 
  parva 
  McChesney 
  

  

  Parallelodon 
  sp. 
  

  

  Myalina 
  orthonota 
  Mather 
  

  

  Aviculopecten 
  arkansanus 
  Mather 
  ? 
  

  

  Aviculopecten 
  sp. 
  

  

  Euphemus 
  carbonarius 
  (Cox) 
  

  

  Griffithides 
  morrowensis 
  Mather? 
  

  

  All 
  the 
  genera 
  listed 
  above 
  are 
  present 
  in 
  the 
  fauna 
  of 
  the 
  

   Morrow 
  group, 
  and 
  17 
  of 
  the 
  21 
  species 
  have 
  been 
  found 
  in 
  

   the 
  limestones 
  of 
  that 
  group. 
  This 
  includes 
  all 
  the 
  forms 
  spe- 
  

   cifically 
  identifiable 
  with 
  the 
  exception 
  of 
  the 
  new 
  species 
  of 
  

   Cromyocrinus. 
  

  

  It 
  is 
  significant 
  that 
  none 
  of 
  these 
  is 
  known 
  from 
  the 
  Kessler 
  

   horizon 
  without 
  also 
  being 
  present 
  in 
  the 
  Hale 
  or 
  Brentwood, 
  

   while 
  several 
  of 
  the 
  Wapanucka 
  forms 
  are 
  not 
  known 
  to 
  occur 
  

   in 
  the 
  Boston 
  Mountains 
  region 
  above 
  the 
  Brentwood 
  member. 
  

   Moreover, 
  none 
  is 
  recorded 
  from 
  the 
  Hale 
  limestone 
  lenses, 
  

   which 
  is 
  not 
  also 
  known 
  from 
  the 
  Brentwood 
  or 
  higher 
  strata. 
  

   (JVucida 
  parva 
  is 
  frequently 
  found 
  in 
  the 
  kl 
  Coal 
  Measures 
  " 
  

   of 
  the 
  Mississippi 
  Valley.) 
  That 
  the 
  Wapanucka 
  is 
  the 
  homo- 
  

   taxial 
  equivalent 
  of 
  the 
  Brentwood 
  is 
  further 
  indicated 
  by 
  the 
  

   association 
  of 
  Pentremites 
  angustus 
  and 
  Spiriferina 
  trans- 
  

   versa, 
  residual 
  Mississippian 
  types, 
  with 
  Rhipidomella 
  pecosi, 
  

   Productus 
  nanus?, 
  Spirifer 
  opimus, 
  Squamularia 
  perplexa, 
  

   and 
  Euphemus 
  carbonarius, 
  proemial 
  Pennsylvanian 
  forms, 
  

   and 
  Composita 
  gibbosa, 
  a 
  characteristic 
  Brentwood 
  species. 
  It 
  

   necessarily 
  follows 
  that 
  the 
  Wapanucka 
  is 
  of 
  early 
  Pottsville 
  

   a^e. 
  

  

  The 
  fauna 
  of 
  the 
  Atoka 
  formation. 
  

  

  The 
  Atoka 
  formation 
  is 
  nearly 
  everywhere 
  barren 
  of 
  fossils 
  ; 
  

   indeed 
  it 
  is 
  highly 
  probable 
  that 
  the 
  formation 
  is 
  in 
  part 
  of 
  

   non-marine 
  origin. 
  There 
  are, 
  however, 
  local 
  beds 
  of 
  calcareous 
  

   sandstone 
  near 
  the 
  base 
  of 
  the 
  formation, 
  which 
  are 
  crowded 
  

  

  