﻿Vol. 
  53.] 
  THE 
  CRETACEOUS 
  STRATA 
  OF 
  COUNTY 
  ANTRIM. 
  549 
  

  

  beds, 
  which 
  here 
  attain 
  a 
  considerable 
  development, 
  Avicula 
  con- 
  

   torta, 
  Portl., 
  Cardium 
  rliceticum, 
  Merian, 
  and 
  Pecten 
  valoniensis, 
  

   Defr., 
  being 
  especially 
  abundant 
  in 
  the 
  shales. 
  These 
  Avicula- 
  

   shales 
  contain 
  a 
  bone-bed, 
  which, 
  from 
  specimens 
  in 
  Mr. 
  Swanston's 
  

   collection, 
  must 
  be 
  as 
  clearly 
  marked 
  as 
  those 
  in 
  the 
  AVest 
  of 
  

   England. 
  Although 
  we 
  did 
  not 
  find 
  the 
  main 
  band, 
  teeth 
  (probably 
  

   of 
  tiaurichtliys 
  apicalis, 
  Ag.) 
  and 
  scales 
  were 
  present 
  in 
  considerable 
  

   abundance. 
  The 
  Liassic 
  strata, 
  which 
  have 
  been 
  described 
  in 
  detail 
  

   by 
  Tate, 
  1 
  were 
  not 
  particularly 
  examined, 
  Ammonites 
  [Arietites] 
  

   Johnstoni, 
  Sow., 
  alone 
  having 
  been 
  obtained. 
  

  

  The 
  Glauconitic 
  Sands, 
  forming 
  the 
  base 
  of 
  the 
  Cretaceous, 
  

   at 
  once 
  attract 
  attention, 
  and 
  are 
  at 
  all 
  times 
  easily 
  recognizable, 
  by 
  

   their 
  deep-green, 
  almost 
  blue-green 
  colour, 
  due 
  to 
  the 
  large 
  propor- 
  

   tion 
  of 
  glauconite-grains 
  which 
  they 
  contain. 
  The 
  fossils 
  in 
  these 
  

   strata 
  are 
  numerous 
  and 
  well-preserved, 
  including 
  Exogyra 
  conica, 
  

   var. 
  laevigata, 
  Sow., 
  Pecten 
  [Amussium'] 
  or 
  hi 
  cularis 
  (Mant.), 
  Cucullcea 
  

   carinata, 
  Sow., 
  also 
  teeth 
  of 
  fishes, 
  namely, 
  Corax 
  falcatus, 
  Ag., 
  

   Lamna 
  appendiculata, 
  Ag., 
  and 
  Ptychodus 
  mammillaris, 
  Ag. 
  Casts 
  

   of 
  Trigoniai 
  and 
  Thetis 
  (?) 
  are 
  not 
  uncommon, 
  but 
  the 
  pelecypoda 
  are 
  

   generally 
  in 
  a 
  condition 
  which 
  renders 
  them 
  difficult 
  of 
  identification. 
  

   Fragments 
  of 
  wood 
  are 
  also 
  present, 
  and 
  large 
  quartz-pebbles 
  are 
  not 
  

   infrequent. 
  The 
  fossils 
  are 
  most 
  abundant 
  in 
  a 
  band 
  containing 
  

   phosphatic 
  nodules. 
  Tate 
  gives 
  the 
  thickness 
  as 
  8 
  feet 
  6 
  inches. 
  

  

  The 
  glauconitic 
  sand 
  passes 
  into 
  a 
  grey 
  marl, 
  the 
  lower 
  half 
  of 
  

   which 
  is 
  crowded 
  with 
  Vermicularia 
  concava, 
  Sow., 
  and 
  V. 
  quinque- 
  

   carinata, 
  E-om., 
  fragments 
  of 
  Pecten 
  [Janira] 
  also 
  being 
  noticed. 
  

   The 
  greensand 
  close 
  to 
  the 
  point 
  of 
  junction 
  contains 
  yellowish 
  

   branching 
  enclosures 
  in 
  great 
  abundance, 
  whose 
  origin 
  it 
  is 
  difficult 
  

   to 
  understand. 
  In 
  this 
  upper 
  layer 
  a 
  large 
  Pecten 
  [Janira] 
  

   quinquecostatus, 
  Sow., 
  was 
  found. 
  

  

  The 
  marl, 
  which 
  in 
  its 
  upper 
  part 
  is 
  of 
  a 
  dark 
  blue-grey 
  colour, 
  

   is 
  not 
  much 
  more 
  than 
  2 
  feet 
  thick, 
  the 
  buff-coloured 
  Yellow 
  

   Sandstones 
  above, 
  on 
  the 
  contrary, 
  attaining 
  a 
  thickness 
  of 
  

   30 
  feet, 
  which, 
  as 
  Tate 
  remarks, 
  represents 
  the 
  greatest 
  development 
  

   of 
  the 
  arenaceous 
  series 
  in 
  Ireland. 
  This 
  rock, 
  which 
  contains 
  

   cherty 
  masses, 
  is 
  markedly 
  fossiliferous 
  only 
  along 
  certain 
  bands. 
  

   The 
  fauna 
  includes 
  Ostrea 
  [Alectryonia] 
  carinata, 
  Lam., 
  Pecten 
  

   [Janira] 
  quadricostatus, 
  Lam. 
  (of 
  large 
  size), 
  Vermicularia 
  quinque- 
  

   carinata, 
  Rom. 
  (not 
  uncommon), 
  Lima 
  semisulcata,d! 
  'Orb., 
  L.globosa, 
  

   Sow., 
  Panopcea 
  mandibula, 
  Sow., 
  species 
  of 
  Avicula, 
  Pinna, 
  Trigonia 
  

   (a 
  very 
  fine 
  Tr. 
  scabricula, 
  Lye, 
  is 
  probably 
  from 
  here), 
  and 
  Galeo- 
  

   laria 
  plexus 
  (Sow.). 
  About 
  2 
  feet 
  from 
  the 
  top 
  a 
  band 
  rich 
  in 
  

   Pecten 
  [Janira'] 
  quinquecostatus 
  was 
  met 
  with. 
  

  

  The 
  Yellow 
  Sandstones 
  pass 
  above 
  into 
  a 
  greensand 
  containing 
  a 
  

   Cucullcea 
  and 
  small 
  Ostrea 
  carinata, 
  Lam. 
  The 
  Chloritic 
  Sand- 
  

   stones 
  here 
  consist 
  of 
  alternating 
  hard, 
  calcareous, 
  glauconitic 
  

   sandstones, 
  and 
  softer 
  greensand 
  rocks 
  of 
  the 
  same 
  nature, 
  the 
  latter 
  

   being 
  those 
  that 
  are 
  richest 
  in 
  organic 
  remains. 
  A 
  noticeable 
  feature 
  

  

  1 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  toI. 
  xx. 
  (1864) 
  p. 
  103, 
  & 
  vol. 
  xxiii. 
  (1867) 
  p. 
  297. 
  

  

  