﻿Vol. 
  53.] 
  THE 
  CRETACEOUS 
  STRATA 
  OF 
  COUNTY 
  ANTRIM. 
  567 
  

  

  The 
  cephalopoda, 
  gasteropoda, 
  and 
  small 
  sea-urchins 
  are 
  especially 
  

   noticeable, 
  while 
  many 
  species 
  of 
  polyzoa 
  and 
  foraminifera 
  have 
  

   been 
  obtained 
  by 
  Mr. 
  Joseph 
  "Wright, 
  from 
  the 
  interior 
  of 
  flints. 
  

   From 
  Benbradagh 
  we 
  are 
  able 
  to 
  record 
  a 
  large 
  Pecten, 
  Area 
  sp., 
  

   Trochus 
  sp., 
  Baculites 
  anceps, 
  Lam., 
  Hamites 
  s])., 
  and 
  Anisoceras 
  sp. 
  ; 
  

   from 
  Dungiven, 
  Dianchora, 
  casts 
  of 
  corals 
  (possibly 
  Trochosmilian), 
  

   Ammonites 
  \_Pachy 
  discus] 
  G-riffibhii, 
  Sharpe, 
  A. 
  [P.] 
  Oldhami, 
  Sh., 
  

   and 
  Belemnitella 
  mucronata, 
  Schloth. 
  ; 
  and 
  from 
  Keady, 
  Galerites 
  

   vulgaris 
  and 
  Calliostoma. 
  Dungiven 
  is, 
  moreover, 
  rich 
  in 
  sea- 
  

   urchins 
  {Echinocorys 
  scutatus, 
  Leske, 
  and 
  Galerites 
  abbreviatus, 
  

   Goldf.), 
  Pleurotomarice, 
  and 
  pelecypoda, 
  including 
  Spondylus 
  spinosus, 
  

   Sow., 
  Ostrea 
  vesicularis, 
  Lam., 
  and 
  Pecten 
  \_Janira] 
  quinquecostatus, 
  

   Sow., 
  besides 
  numerous 
  dimyaria, 
  which 
  have 
  been 
  referred 
  by 
  the 
  

   officers 
  of 
  the 
  Geological 
  Survey 
  to 
  Nucula, 
  Thetis, 
  etc. 
  Among 
  

   brachiopoda 
  may 
  be 
  mentioned 
  Rhynchonella 
  limbata, 
  Schloth., 
  Rh. 
  

   plicatiUs, 
  Sow. 
  (ordinary 
  and 
  octojplicata 
  varieties), 
  Terebratula 
  

   carnea, 
  Sow., 
  and 
  T. 
  semiglobosa, 
  Sow. 
  

  

  The 
  base 
  of 
  the 
  Chalk 
  near 
  Boyd's 
  Mountain 
  is 
  said 
  to 
  be 
  a 
  com- 
  

   pact 
  sandstone 
  mottled 
  with 
  glauconitic 
  particles. 
  1 
  

  

  The 
  main 
  characteristics 
  of 
  the 
  Peninsular 
  Division 
  are 
  : 
  — 
  

  

  1. 
  The 
  great 
  development 
  of 
  pebble-conglomerates 
  at 
  the 
  base 
  of 
  

  

  the 
  Chalk, 
  which 
  here 
  rests 
  directly 
  on 
  the 
  older 
  rocks. 
  

   These 
  conditions 
  are 
  already 
  suggested 
  in 
  the 
  northern 
  

   portion 
  of 
  the 
  Eastern 
  Division. 
  

  

  2. 
  The 
  presence 
  of 
  well-marked 
  Cretaceous 
  beaches, 
  having 
  a 
  

  

  rich 
  fauna 
  of 
  gasteropoda 
  and 
  small 
  sea-urchins. 
  

  

  3. 
  The 
  abundance 
  of 
  organisms 
  in 
  the 
  lower 
  strata 
  of 
  the 
  White 
  

  

  Limestone, 
  resembling 
  in 
  character 
  those 
  found 
  in 
  a 
  similar 
  

   position 
  in 
  the 
  Central 
  Division. 
  

  

  (5) 
  The 
  Northern 
  Division. 
  

  

  (The 
  Northern 
  Coast 
  of 
  Co. 
  Antrim 
  and 
  Ratnlin 
  I.) 
  

  

  Tircreven 
  Burn. 
  

  

  An 
  examination 
  of 
  this 
  section 
  made 
  by 
  Mr. 
  Stewart 
  and 
  myself, 
  

   in 
  the 
  burn 
  north 
  of 
  Ben 
  Evenagh, 
  proved 
  very 
  disappointing. 
  The 
  

   Cretaceous 
  rocks 
  were 
  displayed 
  in 
  the 
  valley 
  a 
  little 
  below 
  the 
  

   junction 
  of 
  the 
  two 
  streams, 
  the 
  strata 
  dipping 
  at 
  a 
  high 
  angle 
  

   (about 
  15°) 
  up 
  stream, 
  or 
  eastward. 
  They 
  consist 
  in 
  the 
  upper 
  part 
  

   of 
  a 
  nodular 
  pink 
  chalk 
  dotted 
  with 
  glauconitic 
  grains, 
  passing 
  

   below 
  into 
  a 
  more 
  glauconitic 
  limestone, 
  containing 
  Spondylus 
  

   spinosus, 
  Sow., 
  Belemnitella 
  sp., 
  worn 
  Inocerami, 
  and 
  fragments 
  of 
  

   Echinocorys 
  and 
  sponges, 
  a 
  fauna 
  recalling 
  in 
  its 
  character 
  that 
  of 
  

   the 
  Spongiarian 
  zone. 
  Portlock 
  also 
  appears 
  to 
  have 
  found 
  evidence 
  

  

  1 
  Mem. 
  Geol. 
  Surv. 
  Irel. 
  Expl. 
  Sheet 
  12, 
  p. 
  1 
  

  

  