﻿590 
  DE. 
  W. 
  EEASEE 
  HUME 
  ON 
  [DeC. 
  1 
  89 
  7, 
  

  

  In 
  the 
  Central 
  Division 
  these 
  Yellow 
  Sandstones 
  pass 
  insensibly 
  

   into 
  the 
  Chloritic 
  Sandstones. 
  Tate 
  remarks: 
  — 
  'The 
  zone 
  of 
  Ostrea 
  

   carinata 
  represents 
  most 
  certainly 
  a 
  portion 
  of 
  the 
  Upper 
  Greensand 
  

   of 
  England 
  and 
  the 
  Lower 
  Cenomanian 
  of 
  Normandy,' 
  a 
  view 
  

   which, 
  apart 
  from 
  the 
  question 
  of 
  nomenclature 
  previously 
  raised, 
  

   agrees 
  with 
  our 
  own. 
  Barrois 
  submitted 
  4 
  that 
  the 
  sandstones 
  

   with 
  cherts 
  containing 
  Ostrea 
  carinata, 
  Micrabacia 
  coronula, 
  resting 
  

   on 
  the 
  zone 
  of 
  Pecten 
  asper, 
  and 
  containing 
  a 
  Cenomanian 
  fauna 
  

   without 
  admixture, 
  are 
  naturally 
  to 
  be 
  placed 
  on 
  a 
  level 
  with 
  the 
  

   Holaster 
  subglobosus-zone 
  in 
  England.' 
  The 
  lithological 
  character 
  

   of 
  the 
  Yellow 
  Sandstones 
  appears 
  to 
  resemble 
  very 
  closely 
  that 
  of 
  

   the 
  sands 
  with 
  chert, 
  as 
  developed, 
  for 
  instance, 
  at 
  "Warminster. 
  The 
  

   large 
  Pecten 
  [Janira] 
  quadrico 
  status 
  agrees 
  in 
  all 
  respects 
  with 
  those 
  

   occurring 
  in 
  the 
  Warminster 
  Beds, 
  in 
  which 
  Lima 
  semisulcata, 
  

   Janira 
  quinquecostata, 
  Vermicularia 
  concava, 
  and 
  Discoidea 
  subucida 
  

   have 
  also 
  been 
  obtained. 
  1 
  Ostrea 
  carinata 
  has 
  also 
  been 
  recorded 
  

   from 
  the 
  chert-beds 
  at 
  Durdle 
  Cove, 
  Purbeck, 
  by 
  Barrois, 
  2 
  Sand- 
  

   stones 
  with 
  chert-beds 
  of 
  similar 
  nature 
  form 
  Bed 
  5 
  of 
  Meyer, 
  3 
  of 
  

   which 
  Janira 
  quadricostata 
  is 
  a 
  typical 
  fossil. 
  Indeed 
  the 
  suc- 
  

   cession 
  at 
  Colin 
  Glen 
  shows 
  an 
  interesting 
  parallelism 
  when 
  compared 
  

   with 
  Meyer's 
  Beds 
  : 
  — 
  

  

  The 
  lowest 
  Yellow 
  Sandstone 
  with 
  cherts 
  and 
  J. 
  quadricostata 
  is 
  1 
  x> 
  j 
  k 
  

   similar 
  to 
  J 
  e 
  

  

  The 
  middle 
  Yellow 
  Sandstone 
  with 
  large 
  Ostrecs 
  is 
  similar 
  to 
  Bed 
  7 
  

  

  The 
  base 
  of 
  the 
  Chloritic 
  Sands 
  with 
  Orbitolina 
  concava 
  and 
  Bhyn- 
  1 
  -r. 
  -, 
  q 
  

   cJionella 
  Schlcenbacki 
  is 
  similar 
  to 
  J 
  e 
  

  

  The 
  Exogyra 
  columba- 
  and 
  Callianassa-beds 
  with 
  polyzoa 
  are 
  1 
  -d 
  j 
  i 
  -i 
  

   similar 
  to 
  j 
  e 
  

  

  At 
  Colin 
  Glen 
  the 
  Yellow 
  Sandstone 
  corresponds 
  nearly 
  in 
  its 
  

   fauna 
  with 
  Beds 
  5-7 
  of 
  Meyer 
  : 
  that 
  is, 
  the 
  upper 
  portion 
  of 
  the 
  

   Devizes 
  beds, 
  or 
  zone 
  of 
  Ammonites 
  inflatus. 
  In 
  his 
  Bed 
  10 
  occur 
  

   together 
  some 
  of 
  the 
  most 
  characteristic 
  of 
  the 
  fossils 
  mentioned 
  

   above, 
  including 
  Ostrea 
  [Alectryonia] 
  carinata, 
  Pecten 
  [Janira] 
  

   quinquecostatus, 
  Sow., 
  Rliynchonella 
  dimidiata, 
  var. 
  convexa, 
  Sow., 
  

   Lima 
  semisidcata, 
  d'Orb., 
  and 
  Discoidea 
  subucula, 
  Klein. 
  It 
  there- 
  

   fore 
  appears 
  probable 
  that 
  the 
  Yellow 
  Sandstones 
  correspond 
  as 
  a 
  

   whole 
  with 
  Beds 
  5-10 
  of 
  Meyer, 
  and 
  are 
  mainly 
  parallel 
  with 
  the 
  

   Warminster 
  greensands, 
  or 
  Pecten 
  asper-zoiie. 
  We 
  have 
  not 
  been 
  

   able 
  to 
  substantiate 
  the 
  presence 
  of 
  Holaster 
  subglobosus, 
  Leske, 
  

   but 
  Ammonites 
  [Acanihoceras] 
  rotomagensis 
  (Defr.) 
  appears 
  to 
  

   have 
  been 
  found 
  in 
  this 
  formation 
  from 
  Sallagh, 
  a 
  specimen 
  of 
  it 
  

   being 
  present 
  from 
  this 
  horizon 
  in 
  the 
  Belfast 
  Museum. 
  There 
  is 
  

   therefore 
  a 
  possibility 
  that 
  the 
  Cenomanian 
  fauna 
  was 
  already 
  

   foreshadowed 
  in 
  the 
  Eastern 
  Division. 
  

  

  We 
  conclude 
  that 
  the 
  Yellow 
  Sandstones 
  are 
  mainly 
  of 
  War- 
  

   minster 
  or 
  Pecten 
  asper-age, 
  but 
  that 
  they 
  still 
  possess, 
  in 
  the 
  

   shallower- 
  water 
  Central 
  Division, 
  an 
  admixture 
  of 
  the 
  fauna 
  of 
  the 
  

  

  1 
  A. 
  J. 
  Jukes-Browne, 
  Geol. 
  Mag. 
  1896, 
  p. 
  261. 
  

  

  2 
  ' 
  Recherches 
  sur 
  le 
  Terrain 
  Cretace. 
  Superieur, 
  etc.,' 
  p. 
  92. 
  

  

  3 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xxx. 
  (1874) 
  p. 
  373. 
  

  

  