﻿90 
  MR. 
  F. 
  R. 
  COWPER 
  REED 
  ON 
  THE 
  [Feb. 
  1 
  89 
  7, 
  

  

  Calymene 
  Blumenbachi, 
  var. 
  Caractaci, 
  Sphcerexochus 
  mirus, 
  Ulcenus 
  

   Bowmani, 
  Lichas 
  laxatus. 
  

  

  In 
  the 
  Upper 
  Bala 
  beds 
  the 
  following 
  Keisley 
  species 
  are 
  

   found 
  : 
  — 
  Cheirurus 
  bimucronatus, 
  Ch. 
  clavifrons, 
  (?) 
  Sphcerexochus 
  

   mirus, 
  Lichas 
  laxatus, 
  Illcenns 
  Bowmani, 
  *Remopleurides 
  longi- 
  

   costatus, 
  *Phillipsinella 
  parabola, 
  Staurocephalus 
  Murchisoni, 
  and 
  

   Calymene 
  Blumenbachi. 
  

  

  Of 
  these 
  the 
  two 
  species 
  marked 
  * 
  are 
  in 
  Britain 
  known 
  only 
  

   in 
  the 
  Upper 
  Bala 
  (excepting, 
  of 
  course 
  the 
  Kildare 
  and 
  Keisley 
  

   Limestones). 
  Ch. 
  bimucronatus, 
  Sph. 
  minis, 
  C. 
  Blumenbachi, 
  

   and 
  St. 
  Murchisoni 
  pass 
  up 
  into 
  the 
  Silurian. 
  Lichas 
  hibernicus, 
  

   curiously 
  enough, 
  occurs 
  elsewhere 
  only 
  in 
  the 
  Craighead 
  Lime- 
  

   stone 
  of 
  Scotland. 
  /. 
  Bowmani 
  and 
  Sph. 
  mirus 
  also 
  occur 
  in 
  the 
  

   Scottish 
  Lower 
  Bala. 
  1 
  

  

  Thus, 
  of 
  the 
  10 
  species 
  found 
  in 
  other 
  British 
  rocks, 
  3 
  occur 
  in 
  

   the 
  Lower 
  Bala, 
  6 
  in 
  the 
  Middle 
  Bala, 
  9 
  in 
  the 
  Upper 
  Bala, 
  and 
  4 
  

   pass 
  up 
  into 
  the 
  Silurian. 
  But 
  in 
  spite 
  of 
  this 
  apparent 
  great 
  

   resemblance 
  to 
  the 
  Upper 
  Bala, 
  we 
  must 
  remember 
  that 
  the 
  absence 
  

   of 
  all 
  species 
  of 
  Trinucleus 
  and 
  Phacops, 
  especially 
  Tr. 
  seticornis 
  

   and 
  Ph. 
  eucentra, 
  characteristic 
  forms 
  of 
  the 
  Upper 
  Bala, 
  2 
  marks 
  

   an 
  important 
  difference. 
  

  

  Summing 
  up, 
  we 
  obtain 
  the 
  following 
  percentage 
  results 
  with 
  

   respect 
  to 
  the 
  species 
  of 
  trilobites 
  from 
  Keisley 
  : 
  — 
  

  

  (i) 
  50 
  °/ 
  occur 
  in 
  the 
  Kildare 
  Limestone. 
  

   (ii) 
  25 
  °/ 
  occur 
  in 
  the 
  Leptcena-Limestone. 
  

   (iii) 
  25 
  °/ 
  occur 
  in 
  British 
  Bala 
  or 
  Silurian 
  beds, 
  and 
  of 
  these 
  

  

  about 
  99 
  °/ 
  occur 
  in 
  Upper 
  Bala 
  beds, 
  

   (iv) 
  Over 
  70 
  °/ 
  occur 
  in 
  no 
  other 
  British 
  bed. 
  

   (v) 
  About 
  16 
  % 
  are 
  peculiar 
  to 
  the 
  Keisley 
  Limestone. 
  

  

  The 
  peculiarity 
  of 
  the 
  trilobitic 
  fauna 
  of 
  this 
  bed 
  is 
  thus 
  plainly 
  

   shown. 
  

  

  IT. 
  Ostracoda. 
  — 
  Both 
  the 
  Keisley 
  species 
  occur 
  at 
  Kildare, 
  and 
  

  

  these 
  are 
  the 
  only 
  two 
  localities 
  in 
  which 
  one 
  form 
  (Cy 
  there 
  

  

  Wrightiana) 
  is 
  known 
  to 
  occur, 
  while 
  Primitia 
  M-Coyi, 
  the 
  other 
  

  

  species, 
  is 
  known 
  elsewhere 
  from 
  the 
  limestone 
  of 
  Aldeans 
  on 
  the 
  

  

  Stinchar 
  Biver. 
  3 
  

  

  III. 
  Brachiopoda. 
  — 
  The 
  foregoing 
  list 
  of 
  the 
  fossils 
  of 
  the 
  

   Keisley 
  Limestone 
  shows 
  (p. 
  86) 
  that 
  out 
  of 
  the 
  37 
  species 
  of 
  

   brachiopoda, 
  19 
  — 
  or 
  over 
  50 
  °/ 
  — 
  are 
  a 
  ^ 
  so 
  found 
  at 
  Kildare, 
  and 
  

   several 
  others 
  probably 
  occur. 
  In 
  the 
  Leptoena 
  -Limestone 
  4 
  12 
  of 
  

  

  1 
  Nicholson 
  & 
  Etheridge, 
  « 
  Mon. 
  Silur. 
  Foss. 
  Giry.' 
  1879 
  ; 
  Lapworth, 
  Quart. 
  

   Journ. 
  Geol. 
  Soc. 
  vol. 
  xxxviii. 
  (1882) 
  p. 
  537. 
  

  

  2 
  Marr 
  & 
  Eoberts, 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xli. 
  (1885) 
  p. 
  476. 
  

  

  3 
  Ann. 
  Mag. 
  Nat. 
  Hist. 
  ser. 
  4, 
  vol. 
  ii. 
  (1868) 
  p. 
  56. 
  

  

  4 
  In 
  the 
  case 
  of 
  the 
  ie^^wa-Limestone 
  I 
  have 
  made 
  use 
  of 
  the 
  specimens 
  in 
  

   the 
  Woodwardian 
  Museum, 
  Tornquist's 
  list 
  in 
  ' 
  Ofvers. 
  6. 
  Bergbygn. 
  in 
  Siljans. 
  

   i 
  Dal.' 
  p. 
  26, 
  Sveriges 
  Geol. 
  Undersokn. 
  ser. 
  c, 
  no. 
  57, 
  and 
  the 
  ( 
  List 
  of 
  the 
  

   Fossil 
  Faunas 
  of 
  Sweden,' 
  published 
  by 
  the 
  Stockholm 
  Museum 
  in 
  1888. 
  

  

  