﻿580 
  3>K. 
  W. 
  TEA 
  SEE 
  HTJME 
  ON 
  [Dec. 
  1 
  897, 
  

  

  C 
  (not 
  traversing 
  a 
  sieve 
  of 
  120 
  meshes 
  to 
  the 
  inch). 
  Colourless 
  

   quartz-grains 
  make 
  up 
  the 
  greater 
  part 
  of 
  this 
  residue, 
  the 
  remainder 
  

   consisting 
  almost 
  entirely 
  of 
  dark-green 
  and 
  yellow-green 
  glauconite, 
  

   the 
  former 
  showing 
  the 
  characteristic 
  rounded 
  outlines. 
  

  

  D. 
  The 
  finest 
  material 
  is 
  composed 
  of 
  very 
  fine 
  grains 
  of 
  quartz 
  

   and 
  glauconite, 
  the 
  former 
  highly 
  angular, 
  and 
  either 
  colourless 
  or 
  

   pale 
  yellow. 
  Mica-flakes 
  are 
  numerous. 
  By 
  means 
  of 
  heavy 
  liquid 
  

   (cadmium 
  borotungstate 
  of 
  sp. 
  gr. 
  2*84), 
  a 
  large 
  crop 
  of 
  heavy 
  

   minerals 
  was 
  obtained, 
  including 
  rutile, 
  zircon, 
  tourmaline, 
  garnet, 
  

   and 
  chlorite 
  : 
  — 
  

  

  1. 
  Rutile. 
  — 
  In 
  general 
  this 
  mineral 
  shows 
  no 
  evidence 
  of 
  crystal- 
  

   line 
  form, 
  and 
  is 
  of 
  an 
  orange-yellow 
  to 
  a 
  deep-red 
  colour. 
  While 
  

   twinning 
  is 
  not 
  marked 
  in 
  most 
  cases, 
  I 
  have 
  obtained 
  one 
  of 
  the 
  

   peculiar 
  interlaced 
  groups, 
  consisting 
  of 
  a 
  number 
  of 
  intergrown 
  

   twinned 
  needles, 
  to 
  which 
  De 
  Saussure 
  applied 
  the 
  name 
  of 
  

   sagenite. 
  

  

  2. 
  Zircon 
  occurs 
  in 
  definite 
  crystals 
  of 
  prismatic 
  habit, 
  the 
  

   pyramidal 
  terminations 
  being, 
  to 
  some 
  extent, 
  rounded. 
  Colourless 
  

   grains 
  are 
  also 
  not 
  infrequent, 
  the 
  high 
  refractive 
  index 
  and 
  

   polarization-colours 
  rendering 
  them 
  easy 
  of 
  identification. 
  

  

  3. 
  Garnet. 
  — 
  This 
  mineral 
  is 
  present 
  in 
  the 
  form 
  of 
  pink-coloured 
  

   fragments 
  and 
  perfectly 
  formed 
  crystals 
  : 
  the 
  latter, 
  owing 
  to 
  the 
  

   unequal 
  development 
  of 
  the 
  faces 
  of 
  the 
  rhombic 
  dodecahedron, 
  

   often 
  appear 
  to 
  have 
  a 
  prismatic 
  habit. 
  Cleavage 
  being 
  wanting, 
  

   the 
  fracture-surfaces 
  are 
  usually 
  irregular, 
  and 
  both 
  fragments 
  and 
  

   crystals 
  are, 
  generally 
  speaking, 
  isotropic. 
  It 
  is 
  very 
  common 
  in 
  the 
  

   residue. 
  

  

  4. 
  Tourmaline. 
  — 
  A 
  few 
  crystals 
  are 
  present, 
  showing 
  the 
  rhom- 
  

   bohedral 
  terminations 
  and 
  characteristically 
  strong 
  absorption. 
  

  

  5. 
  Chlorite 
  occurs 
  in 
  green 
  flakes, 
  when 
  perfect 
  showing 
  hexa- 
  

   gonal 
  outlines, 
  but 
  not 
  usually 
  displaying 
  strong 
  pleochroism. 
  

  

  The 
  most 
  noticeable 
  feature 
  of 
  this 
  conglomerate 
  is 
  therefore 
  

   the 
  abundance 
  and 
  variety 
  of 
  the 
  detrital 
  materials. 
  

  

  White 
  Limestone 
  immediately 
  above 
  the 
  Conglomerate. 
  

   (No. 
  11 
  in 
  Table 
  II.) 
  

  

  This 
  consisted 
  of 
  a 
  white 
  chalk 
  in 
  which 
  a 
  few 
  pebbles 
  of 
  quartz 
  

   were 
  embedded. 
  

  

  The 
  original 
  weight 
  after 
  drying 
  = 
  79*23 
  grammes. 
  After 
  solution 
  

   there 
  remained 
  3*35 
  grammes 
  of 
  residue 
  = 
  4-24 
  %, 
  or 
  

  

  Main 
  residue 
  (clay, 
  etc.) 
  ... 
  = 
  T82 
  gr. 
  = 
  2-29% 
  

  

  Heavy 
  residue 
  = 
  1-538 
  „ 
  = 
  1'94% 
  

  

  Carbonate 
  of 
  lime 
  9577% 
  

  

  100 
  

  

  The 
  heavy 
  residue 
  was 
  further 
  subdivided 
  into 
  : 
  — 
  

   (a) 
  Silicified 
  Inoceramus-tests='140 
  gramme. 
  These 
  consist 
  of 
  

   snow-white 
  rectangular 
  blocks, 
  which 
  show 
  when 
  fractured 
  columnar 
  

  

  