﻿Vol. 
  53.] 
  FAUNA 
  OP 
  THE 
  KEISLEY 
  LIMESTONE. 
  83 
  

  

  may 
  at 
  some 
  future 
  date 
  be 
  found 
  associated 
  with 
  the 
  calices, 
  a 
  brief 
  

   description 
  of 
  them 
  will 
  be 
  useful. 
  

  

  One 
  type 
  (a) 
  consists 
  of 
  thin 
  circular 
  ossicles 
  furnished 
  with 
  a 
  

   strong 
  rounded 
  projecting 
  ridge 
  on 
  the 
  periphery, 
  occupying 
  rather 
  

   more 
  than 
  one-third 
  of 
  the 
  width. 
  

  

  Another 
  common 
  type 
  ((d) 
  is 
  composed 
  of 
  large, 
  plain, 
  smooth 
  

   ossicles, 
  unornamented, 
  and 
  all 
  of 
  equal 
  size, 
  forming 
  a 
  regular, 
  

   smooth, 
  cylindrical 
  column. 
  

  

  Yet 
  another 
  type 
  (y) 
  is 
  quadrangular 
  in 
  section, 
  and 
  composed 
  

   of 
  alternating 
  thick 
  and 
  thin 
  ossicles 
  with 
  a 
  large 
  central 
  canal. 
  

  

  A 
  fourth 
  type 
  (£) 
  consists 
  of 
  circular 
  ossicles, 
  with 
  a 
  thickness 
  of 
  

   about 
  one-fourth 
  of 
  the 
  diameter 
  of 
  the 
  stem, 
  and 
  all 
  of 
  the 
  same 
  

   size. 
  A 
  narrow, 
  smooth, 
  marginal 
  ring 
  surrounds 
  the 
  front 
  edge, 
  

   and 
  a 
  series 
  of 
  fine 
  concentric 
  lines 
  with 
  a 
  single 
  median 
  circlet 
  of 
  

   tubercles 
  adorn 
  the 
  rest 
  of 
  the 
  periphery. 
  There 
  is 
  a 
  large 
  central 
  

   canal, 
  with 
  the 
  margins 
  radially 
  striated. 
  

  

  Another 
  type 
  (e) 
  is 
  composed 
  of 
  circular 
  thick 
  ossicles 
  of 
  equal 
  

   size, 
  with 
  a 
  rounded 
  periphery 
  ornamented 
  with 
  eight 
  or 
  nine 
  

   longitudinally-elongated 
  tubercles. 
  The 
  central 
  canal 
  is 
  very 
  

   small. 
  

  

  A 
  sixth 
  type 
  (£) 
  of 
  stem 
  shows 
  a 
  pentagonal 
  section 
  with 
  a 
  

   central 
  canal 
  of 
  about 
  one-fourth 
  the 
  diameter 
  of 
  the 
  stem. 
  And 
  

   finally 
  there 
  is 
  another 
  type 
  (/?), 
  which 
  has 
  a 
  circular 
  section, 
  and 
  

   is 
  composed 
  of 
  thin 
  ossicles 
  ornamented 
  with 
  encircling 
  threads 
  

   swelling 
  into 
  irregularly-disposed 
  low 
  tubercles. 
  

  

  ACTINOZOA. 
  

  

  Streptelasma 
  europium, 
  F. 
  Romer. 
  

  

  This 
  species 
  seems 
  to 
  be 
  the 
  commonest 
  coral 
  at 
  Keisley. 
  It 
  

   occurs 
  also 
  in 
  the 
  Borkholm 
  * 
  and 
  Lyckholm 
  zones, 
  2 
  in 
  the 
  Sadewitz 
  

   drift-pebbles, 
  3 
  and 
  is 
  common 
  in 
  the 
  Craighead 
  Limestone. 
  4 
  

  

  Halysites 
  catenulaeia, 
  L. 
  

  

  In 
  England 
  this 
  species 
  ranges 
  from 
  the 
  Bala 
  to 
  the 
  Silurian. 
  I 
  

   have 
  seen 
  only 
  one 
  specimen 
  from 
  Keisley. 
  It 
  occurs 
  also 
  in 
  the 
  

   Kildare 
  Limestone, 
  in 
  the 
  Leptcena-Limestone, 
  and 
  in 
  the 
  Lyck- 
  

   holm 
  zone. 
  5 
  

  

  1 
  W. 
  Weissermel, 
  'Die 
  Korallen 
  d. 
  Silurgesch. 
  Ostpreuss.,' 
  Zeitschr. 
  d. 
  

   Deutsch. 
  geol. 
  Gesellsch. 
  vol. 
  xlvi. 
  (1894) 
  p. 
  580. 
  

  

  2 
  Fr. 
  Schmidt, 
  ' 
  Eev. 
  d. 
  ostbalt. 
  Silur. 
  Trilob.,' 
  pt. 
  i. 
  Mem. 
  Acad. 
  Imp. 
  des 
  

   Sci. 
  St. 
  Petersbourg, 
  ser. 
  7, 
  vol. 
  xxx. 
  (1881) 
  no. 
  1, 
  p. 
  38. 
  

  

  3 
  F. 
  Romer, 
  ' 
  Die 
  foss. 
  Fauna 
  d. 
  Silur. 
  diluv. 
  Gesch. 
  v. 
  Sadewitz,' 
  Breslau, 
  

   1861, 
  p. 
  16, 
  pi. 
  iv. 
  fig. 
  1. 
  

  

  4 
  Nicholson 
  & 
  Etheridge, 
  ' 
  Mon. 
  Silur. 
  Foss. 
  Girvan,' 
  1878, 
  p. 
  76, 
  pi. 
  yi. 
  

   figs. 
  1, 
  16. 
  

  

  5 
  Weissermel, 
  op. 
  supra 
  cit. 
  p. 
  661. 
  

  

  