﻿INTRUSIVE 
  ROCKS. 
  151 
  

  

  veins 
  of 
  quartz 
  and 
  steatite, 
  quantities 
  of 
  the 
  vein-stuff 
  are 
  seen 
  scattered 
  

   over 
  the 
  face 
  of 
  the 
  hill, 
  the 
  debris 
  evidently 
  of 
  veins 
  traversing 
  the 
  

   rocks 
  at 
  this 
  spot. 
  Most 
  of 
  the 
  veins 
  are 
  of 
  the 
  usual 
  small 
  dimensions, 
  

   but 
  some 
  veins 
  here 
  are 
  far 
  larger 
  than 
  any 
  noticed 
  elsewhere, 
  being 
  

   nearly 
  a 
  foot 
  thick, 
  whereas 
  elsewhere 
  they 
  are 
  rarely 
  seen 
  more 
  than 
  a 
  

   few 
  inches. 
  These 
  veins 
  are 
  composed 
  of 
  the 
  ordinary 
  union 
  of 
  steatite 
  

   and 
  white 
  fibrous 
  quartz, 
  having 
  more 
  or 
  less 
  of 
  a 
  chatoyant 
  lustre. 
  

   The 
  steatite 
  is 
  of 
  the 
  ordinary 
  gray 
  or 
  green 
  color, 
  hard 
  and 
  compact 
  in 
  

   the 
  thicker 
  parts 
  of 
  a 
  vein, 
  but 
  passing 
  into 
  the 
  finer 
  variety 
  usually 
  

   selected 
  for 
  writing-purposes. 
  The 
  surface 
  of 
  the 
  finer 
  portions 
  of 
  the 
  

   steatite 
  is 
  smooth 
  and 
  burnished, 
  and 
  the 
  mineral 
  exhibits 
  a 
  tendency 
  to 
  

   develope 
  curved 
  ends, 
  resembling 
  cloves 
  of 
  garlic 
  or 
  similar 
  bulbs 
  ; 
  and 
  

   this 
  is 
  not 
  the 
  result 
  of 
  pressure, 
  but 
  of 
  an 
  appropriate 
  segregative 
  pro- 
  

   cess 
  during 
  the 
  formation 
  of 
  the 
  mineral, 
  which 
  is 
  also 
  well 
  seen 
  at 
  

   Shynbaiahn 
  hill. 
  The 
  fibrous 
  quartz 
  is 
  here 
  seen 
  in 
  veins, 
  some 
  two 
  or 
  

   three 
  inches 
  across, 
  and 
  the 
  thicker 
  veins 
  are 
  composed 
  not 
  of 
  so 
  much, 
  

   quartz 
  or 
  steatite, 
  but 
  of 
  an 
  interlaced 
  mass 
  of 
  small 
  veins 
  which 
  unite 
  

   to 
  form 
  one 
  of 
  the 
  above 
  dimensions. 
  On 
  the 
  top 
  of 
  a 
  small 
  rise 
  a 
  

   shallow 
  pit 
  has 
  been 
  sunk 
  a 
  few 
  feet 
  in 
  the 
  ground 
  in 
  search 
  of 
  steatite, 
  

   around 
  which, 
  among 
  much 
  vein-stuff, 
  large 
  lumps 
  of 
  a 
  black 
  shale 
  

   are 
  scattered, 
  as 
  though 
  it 
  formed 
  the 
  underlying 
  rock 
  at 
  the 
  spot. 
  I 
  term 
  

   it 
  a 
  shale, 
  as 
  such 
  I 
  believe 
  is 
  its 
  nature, 
  but 
  in 
  hand 
  specimens 
  it 
  might 
  

   be 
  termed 
  a 
  ' 
  potstone/ 
  so 
  compact 
  and 
  homogeneous 
  is 
  it, 
  in 
  this 
  respect 
  

   resembling 
  the 
  massive 
  shale 
  seen 
  at 
  the 
  foot 
  of 
  Shynbaiahn 
  hill. 
  

  

  A 
  specimen 
  of 
  steatite 
  analysed 
  by 
  Mr. 
  Tween 
  gave 
  the 
  following 
  

   result 
  :— 
  

  

  Water 
  ... 
  ... 
  ... 
  ... 
  2'4 
  

  

  * 
  Si]i 
  ca 
  •■• 
  ••• 
  ..: 
  ... 
  63-11 
  

  

  Oxides 
  of 
  iron 
  and 
  alumina 
  ... 
  ... 
  3-41 
  

  

  Magnesia 
  ... 
  ... 
  ... 
  ... 
  30-47 
  

  

  Alkali 
  ... 
  ... 
  ... 
  ... 
  a 
  trace. 
  

  

  99-39 
  

  

  ( 
  339 
  ) 
  

  

  