﻿INTRUSIVE 
  ROCKS. 
  149 
  

  

  places 
  where 
  no 
  serpentine 
  is 
  known 
  to 
  occur. 
  Whatever 
  relation, 
  

   however, 
  it 
  may 
  bear 
  to 
  the 
  serpentine 
  above 
  described, 
  it 
  is 
  the 
  result 
  

   of 
  chemical 
  segregation, 
  in 
  veins 
  which 
  traverse 
  the 
  altered 
  sedimentary- 
  

   rocks, 
  of 
  both 
  the 
  Axial 
  and 
  Negrais 
  groups. 
  It 
  is 
  everywhere 
  accom- 
  

   panied 
  by 
  a 
  curious 
  variety 
  of 
  quartz, 
  fibrous 
  in 
  structure 
  like 
  satin 
  

   spar, 
  and 
  the 
  intimate 
  connexion 
  between 
  which 
  indicates 
  their 
  cotem- 
  

   porary 
  origin. 
  I 
  did 
  not 
  notice 
  any 
  in 
  the 
  vicinity 
  of 
  the 
  Bidoung 
  ser- 
  

   pentine, 
  but 
  to 
  the 
  South 
  it 
  is 
  commonly 
  found 
  in 
  the 
  vicinity 
  of 
  that 
  

   rock, 
  and 
  in 
  some 
  places 
  is 
  distinctly 
  the 
  result 
  of 
  a 
  metamorphic 
  process 
  

   in 
  the 
  argillaceous 
  beds 
  along 
  the 
  serpentine 
  boundary. 
  This 
  is 
  very 
  

   clearly 
  seen 
  at 
  the 
  foot 
  of 
  Shynbaiahn 
  hill, 
  West 
  of 
  the 
  village 
  of 
  Alay- 
  

   khyoung, 
  South 
  of 
  the 
  Maday. 
  The 
  rocks 
  here 
  are 
  the 
  upper 
  Axials, 
  

   and 
  shaly 
  beds 
  are 
  seen 
  within 
  a 
  few 
  feet 
  of 
  the 
  actual 
  serpentine 
  boun- 
  

   dary. 
  In 
  these 
  shales 
  occur 
  beds 
  of 
  from 
  six 
  to 
  twelve 
  inches 
  in 
  thick- 
  

   ness, 
  of 
  what 
  may 
  be 
  termed 
  almost 
  a 
  claystone, 
  which 
  breaks 
  with 
  a 
  

   clean 
  fracture 
  and 
  dull 
  earthy 
  surface, 
  and 
  is 
  a 
  bedded 
  rock 
  altered 
  by 
  its 
  

   close 
  proximity 
  to 
  the 
  serpentine. 
  In 
  some 
  places 
  this 
  earthy 
  rock 
  is 
  

   seen 
  to 
  pass 
  into 
  steatite 
  of 
  the 
  ordinary 
  character 
  of 
  that 
  usually 
  found 
  

   in 
  veins, 
  with 
  its 
  lustrous 
  surface 
  planes 
  and 
  quasi-foliated 
  structure 
  like 
  

   pure 
  spermaceti. 
  The 
  relation 
  here 
  of 
  the 
  pure 
  mineral 
  to 
  the 
  earthy 
  

   layer 
  wherein 
  it 
  occurs, 
  is 
  sufficiently 
  clear, 
  but 
  its 
  more 
  usual 
  mode 
  of 
  

   occurrence 
  is 
  in 
  the 
  form 
  of 
  veins, 
  where 
  its 
  segregative 
  origin 
  is 
  even 
  more 
  

   clearly 
  seen. 
  In 
  this 
  form 
  it 
  is 
  not 
  uncommon 
  along 
  the 
  margin 
  of 
  the 
  

   serpentine 
  at 
  a 
  variety 
  of 
  spots 
  within 
  the 
  whole 
  of 
  the 
  area 
  marked 
  by 
  

   outbursts 
  of 
  that 
  rock, 
  and 
  is 
  also 
  found 
  among 
  the 
  altered 
  rock 
  towards 
  

   Cape 
  Negrais. 
  It 
  occurs 
  here 
  along 
  the 
  shore 
  among 
  altered 
  shale, 
  

   and 
  again 
  a 
  few 
  miles 
  East 
  of 
  Kweng-bo, 
  thirty 
  miles 
  North 
  of 
  Cape 
  

   Negrais, 
  among 
  sandstones, 
  which 
  are 
  indurated 
  and 
  disturbed, 
  but 
  at 
  

   neither 
  of 
  which 
  spots 
  are 
  any 
  intruded 
  rocks 
  visible. 
  At 
  this 
  last 
  

   locality 
  the 
  steatite 
  occurs 
  in 
  veins 
  traversing 
  sandstone 
  (an 
  unusual 
  

   thing, 
  an 
  argillaceous 
  rock 
  being 
  the 
  more 
  usual 
  matrix) 
  lenticularly 
  

  

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