﻿^°1- 
  53-] 
  FAUNA 
  OF 
  THE 
  KEISLEY 
  LIMESTONE. 
  81 
  

  

  cation 
  of 
  our 
  specimen 
  with 
  0. 
  elongata 
  is 
  correct. 
  It 
  does 
  not 
  

   appear 
  to 
  agree 
  with 
  any 
  of 
  Holm's 
  Swedish 
  species. 
  1 
  

  

  Hyolithtjs 
  tkiangtjlakis 
  ? 
  (Portl.). 
  

  

  Prof. 
  Harkness 
  recorded 
  this 
  species 
  from 
  Keisley, 
  and 
  a 
  speci- 
  

   men 
  so 
  labelled 
  is 
  in 
  the 
  Carlisle 
  Museum. 
  I 
  am 
  doubtful 
  as 
  to 
  

   the 
  correctness 
  of 
  this 
  identification, 
  for 
  the 
  rate 
  of 
  tapering 
  of 
  this 
  

   specimen 
  is 
  more 
  rapid, 
  and, 
  unless 
  we 
  regard 
  it 
  as 
  the 
  broken 
  

   pointed 
  end 
  of 
  the 
  shell, 
  it 
  is 
  a 
  much 
  shorter 
  form 
  than 
  that 
  figured 
  

   by 
  Portlock 
  2 
  and 
  in 
  Murchison's 
  ' 
  Siluria.' 
  3 
  

  

  Lamellibranchiata. 
  

  

  Ptekqlea 
  subealcata, 
  Conrad, 
  var. 
  

  

  Shell 
  obliquely 
  oval, 
  subfalcate, 
  narrow, 
  strongly 
  convex 
  ; 
  umbo 
  

   gibbous, 
  acute, 
  projecting 
  above 
  hinge-line. 
  Surface 
  ornamented 
  

   with 
  regular, 
  simple, 
  radiating, 
  straight, 
  fine 
  ribs, 
  of 
  which 
  the 
  

   anterior 
  ones 
  are 
  slightly 
  curved 
  forward. 
  Anterior 
  ear 
  small, 
  

   flat, 
  triangular, 
  sharply 
  marked 
  off 
  from 
  the 
  body 
  of 
  the 
  shell, 
  

   striated. 
  Posterior 
  wing 
  not 
  preserved, 
  but 
  apparently 
  as 
  abruptly 
  

   defined 
  from 
  the 
  body 
  of 
  the 
  shell 
  as 
  the 
  anterior 
  ear. 
  

  

  millim. 
  

  

  Length 
  of 
  shell 
  (obliquely 
  measured) 
  105 
  

  

  Width 
  of 
  same 
  across 
  middle 
  7*0 
  

  

  This 
  shell, 
  which 
  is 
  in 
  the 
  Carlisle 
  Museum, 
  was 
  labelled, 
  appa- 
  

   rently 
  by 
  Harkness, 
  as 
  Pterincea 
  tenuistriata 
  ; 
  its 
  shape 
  and 
  

   ornamentation 
  are, 
  however, 
  completely 
  different. 
  It 
  differs 
  from 
  

   typical 
  specimens 
  of 
  Pt. 
  subfalcata 
  (Conrad) 
  4 
  only 
  by 
  the 
  absence 
  of 
  

   the 
  concentric 
  striae. 
  The 
  type-form 
  of 
  the 
  species 
  occurs 
  in 
  the 
  

   Upper 
  Ludlow. 
  

  

  Anodontopsis, 
  sp. 
  (PI. 
  VI. 
  figs. 
  9 
  & 
  9 
  a.) 
  

  

  Shell 
  small, 
  subcircular, 
  gently 
  convex, 
  most 
  convex 
  near 
  the 
  

   beak 
  ; 
  hinge-line 
  slightly 
  curved 
  ; 
  beak 
  near 
  the 
  anterior 
  end, 
  

   directed 
  forward. 
  The 
  beak 
  rises 
  steeply 
  above 
  a 
  small 
  flattened 
  

   portion 
  immediately 
  in 
  front 
  of 
  it. 
  No 
  muscular 
  scars 
  or 
  pallial 
  

   line 
  visible. 
  Length 
  4*5 
  millim. 
  

  

  M'Coy's 
  Anodontojosis 
  bulla 
  5 
  appears 
  to 
  bear 
  resemblance 
  to 
  this 
  

   Keisley 
  form, 
  but 
  it 
  is 
  with 
  some 
  hesitation 
  that 
  I 
  refer 
  the 
  latter 
  to 
  

   the 
  same 
  genus, 
  since 
  it 
  hardly 
  shows 
  sufficient 
  structural 
  features 
  

  

  1 
  ' 
  SverigesKambr. 
  Silur. 
  Hyolithidse 
  o. 
  Conulariidae,' 
  Sver. 
  Geol. 
  Undersokn. 
  

   ser. 
  c, 
  no. 
  112 
  (1893). 
  

   3 
  ' 
  Eep. 
  Geol. 
  Londond.' 
  (1843) 
  p. 
  375, 
  pi. 
  xxviii. 
  a, 
  figs. 
  3a-c. 
  

  

  3 
  5th 
  ed. 
  p. 
  199, 
  Foss. 
  41, 
  fig. 
  2. 
  

  

  4 
  M'Coy, 
  « 
  Svst. 
  Descr. 
  Brit. 
  Pal. 
  Foss.' 
  (1855) 
  p. 
  263, 
  pi. 
  i. 
  i, 
  fig. 
  3, 
  

  

  5 
  Ibid. 
  p. 
  271, 
  pi. 
  i. 
  k, 
  figs. 
  11-13. 
  

  

  Q. 
  J. 
  G. 
  S. 
  No. 
  209. 
  & 
  

  

  