﻿Vol. 
  53.] 
  THE 
  CRETACEOUS 
  STRATA 
  OF 
  COUNTY 
  ANTRIM. 
  555 
  

  

  by 
  analysis 
  and 
  microscopic 
  study, 
  and 
  the 
  observations 
  resulting 
  

   therefrom 
  will 
  be 
  dealt 
  with 
  in 
  the 
  sequel. 
  

  

  The 
  Glauconitic 
  Sands, 
  which 
  here 
  attain 
  a 
  thickness 
  of 
  

   nearly 
  8 
  feet, 
  are 
  very 
  fossiliferous, 
  especially 
  in 
  a 
  nodular 
  band 
  

   at 
  the 
  centre 
  of 
  the 
  zone, 
  termed 
  by 
  Tate 
  the 
  bed 
  of 
  Exogyra 
  conica. 
  

   Some 
  of 
  these 
  Exogyrce 
  measure 
  as 
  much 
  as 
  2 
  inches 
  or 
  more 
  

   in 
  diameter. 
  In 
  addition 
  Pecten 
  \_Amussium~] 
  orbicularis 
  (Mant.), 
  

   as 
  also 
  species 
  of 
  Area, 
  Inoceramus, 
  and 
  Avicula, 
  attest 
  the 
  great 
  

   richness 
  of 
  the 
  molluscan 
  fauna 
  at 
  this 
  period. 
  The 
  conical 
  casts 
  

   of 
  biconcave 
  vertebrae 
  of 
  fish 
  have 
  also 
  been 
  obtained. 
  Moreover, 
  

   Tate 
  records 
  Belemnites 
  ultimus, 
  Pecten 
  [Chlamys] 
  Dutemplei, 
  P. 
  

   virgatus, 
  and 
  Terebratula 
  squamosa. 
  

  

  The 
  greensands 
  graduate 
  into 
  a 
  dark 
  sandy 
  marl 
  dotted 
  with 
  

   green 
  glauconitic 
  grains, 
  the 
  Glauconitic 
  Marls, 
  which 
  stratum 
  

   forms 
  a 
  connecting-link 
  between 
  the 
  Grey 
  Marls 
  above 
  and 
  the 
  

   Glauconitic 
  Sands 
  below. 
  

  

  The 
  Grey 
  Marls 
  become 
  very 
  light 
  in 
  the 
  upper 
  part, 
  where 
  

   ramifying 
  masses 
  of 
  a 
  glauconitic 
  sandy 
  limestone 
  are 
  scattered 
  

   through 
  them, 
  similar 
  to 
  the 
  rock 
  next 
  to 
  be 
  described. 
  The 
  

   marls, 
  so 
  far 
  as 
  I 
  have 
  observed, 
  are 
  quite 
  unfossiliferous 
  ; 
  but, 
  

   as 
  they 
  contain 
  cherty 
  nodules, 
  they 
  are 
  in 
  all 
  probability 
  merely 
  

   a 
  more 
  clayey 
  facies 
  of 
  the 
  Yellow 
  Sandstone, 
  and 
  are 
  in 
  fact 
  

   quite 
  as 
  rich 
  in 
  detrital 
  material 
  as 
  the 
  Yellow 
  Sandstone 
  of 
  Colin 
  

   Glen. 
  

  

  In 
  the 
  chemical 
  analysis, 
  the 
  marl 
  and 
  enclosed 
  grit 
  have 
  been 
  

   separately 
  treated, 
  and 
  in 
  Table 
  II. 
  [facing 
  p. 
  584] 
  are 
  respectively 
  

   numbered 
  4 
  and 
  4 
  a. 
  Tate 
  gives 
  the 
  marls 
  a 
  thickness 
  of 
  2 
  J 
  feet, 
  

   but 
  my 
  measurements 
  assign 
  1^ 
  feet 
  to 
  the 
  glauconitic 
  dark 
  marls, 
  

   and 
  1| 
  feet 
  to 
  the 
  yellower 
  marls 
  above, 
  or 
  a 
  total 
  of 
  3 
  feet. 
  

  

  The 
  Grey 
  Marls 
  are 
  succeeded 
  by 
  a 
  calcareous 
  glauconitic 
  

   sandstone 
  similar 
  in 
  its 
  nature 
  to 
  the 
  one 
  above-mentioned, 
  and 
  

   the 
  peculiar 
  inclusions 
  already 
  referred 
  to 
  bear 
  out 
  Tate's 
  contention 
  

   that 
  there 
  is 
  an 
  unconformity 
  between 
  this 
  rock 
  and 
  the 
  underlying 
  

   strata. 
  The 
  series 
  shows 
  a 
  gradual 
  change 
  upward, 
  from 
  this 
  

   sandy 
  type 
  to 
  a 
  sandy 
  glauconitic 
  limestone 
  at 
  the 
  summit, 
  but 
  

   about 
  a 
  foot 
  from 
  the 
  base 
  occurs 
  a 
  band, 
  which, 
  from 
  the 
  ease 
  with 
  

   which 
  it 
  is 
  identified, 
  has 
  been 
  used 
  by 
  previous 
  authors 
  as 
  of 
  con- 
  

   siderable 
  importance 
  in 
  their 
  discussions. 
  

  

  Its 
  characteristic 
  feature 
  is 
  the 
  presence 
  of 
  innumerable 
  fragments 
  

   of 
  Inoceramus 
  scattered 
  through 
  a 
  calcareous 
  matrix, 
  rich 
  in 
  

   glauconite- 
  and 
  sand-grains. 
  I 
  have 
  been 
  unable 
  to 
  obtain 
  any 
  

   proof 
  that 
  the 
  Inoceramus 
  present 
  is 
  1". 
  Cripsii, 
  Goldf., 
  non 
  Crispi, 
  

   as 
  suggested 
  by 
  Tate 
  and 
  others, 
  though 
  in 
  his 
  paper 
  there 
  is 
  a 
  

   question-mark 
  against 
  the 
  name. 
  On 
  the 
  other 
  hand, 
  neither 
  has 
  

   any 
  further 
  evidence 
  been 
  forthcoming 
  of 
  their 
  connexion 
  with 
  

   I. 
  Brongniarti, 
  Park., 
  although, 
  judging 
  from 
  their 
  associated 
  fossils, 
  

   they 
  may 
  possibly 
  be 
  referable 
  to 
  that 
  species. 
  The 
  only 
  perfect 
  

   specimen 
  of 
  Inoceramus 
  that 
  I 
  have 
  been 
  able 
  to 
  examine 
  from 
  

   this 
  horizon 
  hails 
  from 
  Armoy, 
  and 
  is 
  a 
  genuine 
  /. 
  Brongniarti. 
  

  

  The 
  principal 
  fossils 
  obtained 
  by 
  me 
  at 
  this 
  locality 
  were 
  

  

  