﻿Quart. 
  Oourn. 
  Geol. 
  Soc, 
  Vol. 
  LIII. 
  

  

  III. 
  — 
  Table 
  illustrating 
  the 
  General 
  Distribution 
  of 
  the 
  Minerals 
  in 
  the 
  Irish 
  Cretaceous 
  Zones. 
  

  

  [To 
  free 
  p. 
  I 
  

  

  m™. 
  

  

  

  

  Yellow 
  

   Sandstones. 
  

  

  Enclosure 
  

  

  IN 
  UPPER 
  PART 
  

  

  of 
  Yellow 
  

   Sandstone. 
  

  

  Inoceramus- 
  

  

  - 
  c 
  rr 
  

  

  White 
  

   Limestone. 
  

  

  Analyses 
  op 
  Muelough 
  Bat 
  Chalk. 
  

  

  Sands. 
  Marls. 
  

  

  Pebble 
  

   Conglomerate. 
  

  

  Chalk 
  above 
  

   Feb. 
  Conql. 
  

  

  Chalk 
  6 
  feet 
  

  

  Chalk 
  12 
  feet 
  

   above. 
  

  

  Chalk 
  18 
  feet 
  

  

  Quart/.. 
  

  

  Abundant. 
  Large 
  

   grains 
  watenvorn. 
  

  

  Abundant. 
  Large 
  

   grains 
  rounded, 
  

   smaller 
  ones 
  

  

  Larger 
  grains 
  

   rounded, 
  angular 
  

   ones 
  abundant. 
  

  

  Large 
  grains 
  

   rounded. 
  

  

  Larger 
  grains 
  

   variable, 
  rounded 
  

   and 
  subangular. 
  

  

  Quartz-grains 
  

  

  Very 
  rare. 
  

  

  Large 
  pebbles 
  

  

  Subangular 
  grains. 
  

  

  Rounded 
  grains, 
  

  

  Small 
  angular 
  

  

  Very 
  rare. 
  

  

  Other 
  forms 
  of 
  

   Silica. 
  

  

  

  

  Small 
  pieces 
  of 
  

   opal 
  abundant. 
  

  

  

  Chalcedonic 
  

   replacements. 
  

  

  Chalcedonic 
  

   replacements. 
  

  

  Chalcedonic 
  films. 
  

  

  

  Chalcedonic 
  films. 
  

  

  Chalcedonic 
  films. 
  

  

  Chalcedonic 
  films. 
  

  

  Chalcedonic 
  films 
  

   abundant. 
  

  

  Felspars. 
  

  

  Orthoclase 
  rare. 
  

  

  

  

  Ortlioclase 
  rare. 
  

  

  

  Abundant 
  

   (kaolinizing). 
  

  

  

  Orthoclase 
  

   abundant. 
  

  

  i 
  

   

  

  

  

  

  

  

  

  

  Micas. 
  

  

  Muscovite 
  and 
  

  

  biotite 
  fairly 
  

  

  Muscovite 
  and 
  

   biotite 
  very 
  

  

  Muscovite 
  very 
  

  

  

  Muscovite 
  

   abundant. 
  

  

  Muscovite 
  

   abundant. 
  

  

  

  Muscovite 
  and 
  

   biotite 
  abundant. 
  

  

  lliotite 
  abundant. 
  

  

  Muscovite-flakes. 
  

  

  

  Pyroxenes 
  and 
  

   Amphiboles. 
  

  

  

  

  Enstatite 
  possibly 
  

  

  

  

  

  

  

  

  

  

  

  

  

  Tourmaline. 
  

  

  Crystals 
  very 
  rare, 
  

  

  Crystals 
  numerous. 
  

  

  In 
  good 
  crystals. 
  

  

  

  Black 
  and 
  grey- 
  

  

  Frequent 
  in 
  

   good 
  crystals. 
  

  

  Very 
  rare. 
  

  

  A 
  few 
  crystals. 
  

  

  Rounded 
  fragments. 
  

  

  

  One 
  fragment. 
  

  

  

  numerous. 
  

  

  

  Zircon. 
  

  

  Rounded 
  grains 
  

  

  Rounded 
  grains 
  

  

  In 
  crystals 
  and 
  

   rounded 
  grains. 
  

  

  Rounded 
  grains 
  Good 
  crystals 
  

   numerous. 
  \ 
  frequent. 
  

  

  Grains 
  present. 
  

  

  Very 
  rare. 
  

  

  Crystals 
  and 
  

  

  Numerous 
  crystals 
  

   and 
  grains. 
  

  

  

  

  Rutile. 
  

  

  Orange 
  -yellow 
  

   Deep-red 
  crystals 
  

  

  Red 
  and 
  orange- 
  

   yellow 
  crystals 
  and 
  

   yellow 
  fragments. 
  

  

  Only 
  in 
  fragments. 
  

  

  Deep-red 
  and 
  yellow 
  

   grains 
  numerous. 
  

  

  Deep-red 
  and 
  

   yellow 
  fragments. 
  

  

  Large 
  yellow 
  

  

  

  Orange-yellow 
  and 
  

   deep-red 
  grains. 
  

  

  „.,_ 
  

  

  One 
  twin 
  of 
  rutile. 
  

  

  

  Anatase. 
  

  

  

  

  One 
  crystal. 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  Garnet. 
  

  

  

  Rare. 
  

  

  

  Perfect 
  crystals 
  

  

  Perfect 
  crystals 
  

  

  Small 
  crystals. 
  

  

  

  Good 
  crystals 
  

   and 
  fragments. 
  

  

  One 
  crystal. 
  

  

  

  

  

  Kyanite. 
  

  

  

  Rare. 
  

  

  

  Frequent. 
  

  

  

  

  

  

  

  

  

  

  

  

  Chlorite. 
  

  

  

  Green 
  flakes 
  not 
  

   uncommon. 
  

  

  Green 
  films 
  

   common. 
  

  

  Green 
  films 
  

  

  j 
  Blue-green 
  flakes. 
  

  

  L 
  _. 
  . 
  

  

  

  Green 
  flakes 
  

   abundant. 
  

  

  Green 
  flakes. 
  

  

  

  Glauconite. 
  

  

  Forming 
  casts 
  of 
  

  

  foraminifera 
  and 
  

  

  ostracoda. 
  Very 
  

  

  abundant. 
  

  

  Abundant 
  in 
  tbe 
  

   form 
  of 
  casts. 
  

  

  grains 
  generally. 
  

  

  | 
  Often 
  as 
  easts 
  1 
  Casts 
  of 
  sponges 
  

   Fairly 
  abundant. 
  of 
  Hexactinellid 
  and 
  foraiuiniiVni 
  

   meshes. 
  numerous. 
  

  

  Very 
  rare. 
  

  

  Abundant 
  in 
  

   irregular 
  masses. 
  

  

  Casts, 
  abuu.lant 
  aggS^and 
  ^S^fSt 
  

   and 
  perfect. 
  -*£jW 
  JSSu£ 
  

  

  Sponge- 
  and 
  

   Eoramiuiferal 
  casts. 
  

  

  Limonite. 
  

  

  

  Common. 
  

  

  

  

  Very 
  abundant. 
  

  

  

  Frequent. 
  

  

  

  Amorphous 
  red 
  

   masses. 
  

  

  

  

  Limonitic 
  rods 
  

   abundant. 
  

  

  

  

  

  

  Pyrite 
  or 
  

   Marcasite. 
  

  

  

  Very 
  abundant 
  

   in 
  rods, 
  films, 
  and 
  

  

  Well-crystallized 
  

   blocks 
  numerous. 
  

  

  Well 
  crystallized. 
  

  

  Cubic 
  crystals 
  

   and 
  aggregates. 
  

  

  

  

  

  

  

  

  

  

  

  

  

  