﻿9S 
  

  

  ME. 
  P. 
  E. 
  COWPER 
  REED 
  ON 
  THE 
  

  

  [Feb. 
  1897, 
  

  

  In 
  addition 
  to 
  the 
  foregoing 
  the 
  following 
  Keisley 
  species 
  occur 
  

   in 
  the 
  Leptcena-JAmeatone 
  : 
  — 
  

  

  Cheirurus 
  (Pseudosphcgrexochus) 
  con- 
  

  

  formis. 
  

   Sphcsrexochus 
  mirus. 
  

   * 
  Sphcsrocoryphe 
  granulata. 
  

   Lichas 
  affinis. 
  

  

  „ 
  laxatus. 
  

   Illcenus 
  fallax. 
  

  

  ,, 
  Roemeri. 
  

   Orthis 
  Actonice. 
  

  

  „ 
  biforata. 
  

  

  Orthis 
  biloba. 
  

  

  ,, 
  calligramma. 
  

  

  Strophomena 
  corrugatella. 
  

  

  Leptmna 
  rhomboidalis. 
  

   ? 
  Eafinesquina 
  deltoidea, 
  var. 
  undata. 
  

  

  Plectambonites 
  Schmidti. 
  

   ? 
  „ 
  quinquecostata. 
  

  

  Hyattella 
  Portlochiana. 
  

   *Heliolites 
  dubia. 
  

  

  Halt/sites 
  catenularia. 
  

  

  The 
  allied 
  but 
  not 
  identical 
  species 
  need 
  not 
  again 
  be 
  mentioned. 
  

   The 
  evidence 
  already 
  adduced 
  is 
  sufficient 
  to 
  show 
  the 
  homotaxial 
  

   equivalence 
  of 
  the 
  beds. 
  

  

  With 
  regard 
  to 
  the 
  Russian 
  beds 
  Schmidt, 
  as 
  above 
  mentioned, 
  

   has 
  insisted 
  that 
  the 
  Leptcena-IAmestone 
  is 
  on 
  the 
  same 
  horizon 
  as 
  

   his 
  Borkholm 
  zone. 
  It 
  is 
  confirmatory 
  of 
  my 
  conclusions 
  as 
  to 
  the 
  

   homotaxial 
  equivalence 
  of 
  these 
  beds 
  that 
  several 
  Kildare 
  fossils 
  

   which 
  do 
  not 
  occur 
  elsewhere 
  in 
  the 
  British 
  Isles 
  are 
  identical 
  with 
  

   species 
  from 
  these 
  Russian 
  beds 
  ; 
  as, 
  for 
  example, 
  Lichas 
  Icevis 
  

   (Eichw.) 
  and 
  L. 
  margaritifer 
  (Nieszk.). 
  

  

  The 
  difficulty 
  as 
  to 
  the 
  strati 
  graphical 
  position 
  of 
  the 
  Leptama- 
  

   Limestone, 
  indeed, 
  enters 
  into 
  the 
  above 
  correlation. 
  The 
  diver- 
  

   gence 
  of 
  opinion 
  on 
  this 
  point 
  is 
  well 
  known. 
  Briefly, 
  one 
  party, 
  

   respresented 
  by 
  Tornquist, 
  places 
  the 
  Leplcena-liimestone 
  above 
  

   the 
  RetiolitesSh&les 
  ; 
  the 
  other 
  party, 
  to 
  which 
  Schmalensee, 
  

   F. 
  Romer, 
  and 
  Marr 
  belong, 
  put 
  it 
  immediately 
  above 
  the 
  Trinucleus- 
  

   Beds 
  and 
  below 
  the 
  Rastrites- 
  Shales. 
  I 
  am 
  not 
  in 
  a 
  position 
  to 
  

   criticize 
  these 
  two 
  views, 
  nor 
  is 
  this 
  the 
  occasion 
  to 
  do 
  so, 
  but 
  I 
  

   may 
  point 
  out 
  that 
  Schmidt 
  has 
  indisputably 
  established 
  the 
  strati- 
  

   graphical 
  position 
  and 
  relations 
  of 
  the 
  Borkholm 
  zone 
  in 
  a 
  region 
  

   in 
  which 
  the 
  succession 
  of 
  the 
  beds 
  is 
  not 
  confused 
  or 
  indistinct 
  

   from 
  deformation 
  or 
  dislocation 
  of 
  the 
  strata 
  ; 
  that 
  he 
  has 
  proved 
  

   it 
  to 
  be 
  at 
  the 
  top 
  of 
  the 
  Ordovician 
  System, 
  and 
  its 
  fauna 
  to 
  be 
  

   essentially 
  identical 
  with 
  that 
  of 
  the 
  Leptcena-IAm 
  estone. 
  

  

  Tornquist 
  1 
  has 
  given 
  the 
  reasons 
  for 
  his 
  view 
  of 
  the 
  case 
  in 
  a 
  

   number 
  of 
  valuable 
  papers. 
  Marr 
  2 
  at 
  first 
  went 
  with 
  him, 
  but 
  

   in 
  1885 
  3 
  rejected 
  that 
  view, 
  although 
  he 
  expressed 
  the 
  opinion 
  that 
  

   the 
  Lep>tama-Lime$tone 
  contained 
  ' 
  a 
  mixture 
  of 
  faunas 
  of 
  several 
  

   of 
  the 
  Haverfordwest 
  beds, 
  viz. 
  the 
  Lower 
  Llandovery, 
  the 
  Tri- 
  

   nucleus 
  seticomis-heds, 
  and 
  perhaps 
  even 
  of 
  the 
  Robeston 
  Wathen 
  

   Limestone.' 
  

  

  1 
  ' 
  Om 
  Lagerfolj. 
  i. 
  Dal. 
  undersil. 
  Bildning.,' 
  K. 
  Vetensk. 
  Akad. 
  Forhandl. 
  

   1867 
  ; 
  ' 
  Geol. 
  Iakt. 
  o. 
  d. 
  Kambr. 
  o. 
  Silur. 
  Lagf. 
  i. 
  Siljans.' 
  Ofv. 
  K 
  Vetensk. 
  Akad. 
  

   Forhandl. 
  1871, 
  no. 
  1 
  ; 
  ' 
  Om 
  Siljans. 
  Pal. 
  Format.' 
  ibid. 
  1874, 
  no. 
  4, 
  p. 
  3 
  ; 
  

   ' 
  Berattelse, 
  etc' 
  ibid. 
  1879, 
  no. 
  2 
  ; 
  Geol. 
  Foren. 
  i 
  Stockholm 
  Forhandl. 
  no. 
  90, 
  

   vol. 
  vii. 
  (1884) 
  pt. 
  6, 
  p. 
  304 
  ; 
  ibid. 
  vol. 
  viii. 
  (1886) 
  ; 
  ibid. 
  vol. 
  xiv. 
  (1892), 
  

   nos. 
  141, 
  147, 
  etc. 
  

  

  2 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xxxviii. 
  (1882) 
  p. 
  313. 
  

  

  3 
  Ibid. 
  vol. 
  xli. 
  (1885) 
  p. 
  489. 
  

  

  