﻿"V°l- 
  53-] 
  SUDBTJKT 
  NICKEL 
  DISTRICT 
  (CANADA). 
  51 
  

  

  boundaries. 
  Grains 
  of 
  chalcopyrite 
  and 
  pyrrhotite 
  are 
  very 
  

   frequent. 
  

  

  In 
  the 
  railway- 
  cutting 
  quite 
  close 
  to 
  the 
  Murray 
  Mines 
  deposit, 
  

   which 
  is 
  very 
  near 
  the 
  south-eastern 
  border 
  of 
  the 
  Whitson 
  Lake 
  

   eruptive, 
  the 
  rock 
  contains 
  a 
  large 
  amount 
  of 
  pyrrhotite 
  and 
  chalco- 
  

   pyrite. 
  It 
  has 
  been 
  much 
  more 
  altered 
  than 
  the 
  rocks 
  already 
  

   described. 
  Hypersthene 
  and 
  augite 
  have 
  entirely 
  disappeared 
  and 
  

   have 
  been 
  replaced 
  by 
  green 
  hornblende, 
  which 
  does 
  not 
  appear 
  to 
  

   be 
  confined 
  to 
  any 
  definite 
  areas. 
  Primary 
  plagioclase 
  cannot 
  be 
  

   detected, 
  but 
  seems 
  to 
  have 
  given 
  place 
  to 
  small 
  individuals 
  which 
  

   are 
  broadly 
  twinned 
  and 
  water-clear. 
  A 
  few 
  scales 
  of 
  biotite, 
  a 
  

   little 
  primary 
  hornblende, 
  numerous 
  small 
  irregular 
  grains 
  of 
  quartz, 
  

   and 
  swarms 
  of 
  pyrrhotite- 
  and 
  chalcopyrite-grains, 
  complete 
  the 
  

   list 
  of 
  constituents. 
  The 
  rock 
  has 
  been 
  almost 
  entirely 
  recrystal- 
  

   lized, 
  and 
  its 
  original 
  nature 
  is 
  somewhat 
  concealed. 
  In 
  composition 
  

   it 
  corresponds 
  at 
  present 
  to 
  an 
  uralitic 
  diorite, 
  and 
  has 
  doubtless 
  

   been 
  derived 
  from 
  a 
  rock 
  of 
  the 
  gabbro 
  family. 
  For 
  convenience, 
  

   these 
  altered 
  norites 
  or 
  gabbros 
  will 
  be 
  referred 
  to 
  in 
  the 
  following 
  

   pages 
  as 
  ' 
  greenstones.' 
  

  

  Although 
  the 
  rocks 
  collected 
  along 
  the 
  railway 
  near 
  Murray 
  

   Mines 
  indicate 
  a 
  total 
  disappearance 
  of 
  hypersthene 
  and 
  a 
  large 
  

   increase 
  of 
  secondary 
  hornblende, 
  yet 
  there 
  is 
  good 
  ground 
  for 
  

   regarding 
  these 
  rocks 
  as 
  having 
  been 
  derived 
  from 
  norite. 
  The 
  

   late 
  Baron 
  von 
  Foullon 
  described 
  a 
  rock 
  which 
  was 
  blasted 
  out 
  

   when 
  the 
  foundations 
  were 
  being 
  prepared 
  for 
  the 
  smelting-works 
  

   at 
  Murray 
  Mines, 
  not 
  more 
  than 
  100 
  yards 
  from 
  the 
  contact. 
  

   This 
  rock 
  is 
  described 
  as 
  containing 
  strongly 
  pleochroic 
  semi- 
  

   idiomorphic 
  hypersthene-crystals, 
  along 
  with 
  a 
  smaller 
  amount 
  of 
  

   diallage. 
  He 
  observes 
  that 
  these 
  minerals 
  are 
  often 
  bordered 
  with 
  

   hornblende. 
  The 
  rock 
  on 
  the 
  dump 
  at 
  Murray 
  Mines 
  is 
  generally 
  

   fine-grained 
  and 
  too 
  much 
  altered 
  to 
  show 
  hypersthene, 
  but 
  in 
  the 
  

   lower 
  workings, 
  10 
  to 
  20 
  yards 
  removed 
  from 
  the 
  contact, 
  the 
  ore 
  

   occurs 
  in 
  a 
  rock 
  of 
  medium 
  grain, 
  which 
  contains 
  an 
  abundance 
  of 
  

   fresh 
  hypersthene. 
  This 
  rock 
  shows 
  a 
  large 
  amount 
  of 
  diallage-like 
  

   augite 
  and 
  secondary 
  hornblende, 
  while 
  plagioclase 
  is 
  not 
  so 
  abundant 
  

   as 
  usual, 
  and 
  has 
  been 
  partly 
  recrystallized. 
  

  

  The 
  contact 
  with 
  the 
  granite 
  on 
  the 
  south-eastern 
  side 
  of 
  the 
  

   eruptive 
  is 
  not 
  very 
  sharp. 
  Granite 
  is 
  mingled 
  with 
  greenstone 
  for 
  

   100 
  to 
  150 
  yards 
  and 
  often 
  forms 
  breccias 
  with 
  it. 
  The 
  breccias 
  

   have 
  a 
  granitic 
  grained 
  matrix, 
  and 
  sharply 
  angular 
  greenstone- 
  

   fragments 
  which 
  vary 
  much 
  in 
  size. 
  The 
  granite 
  is 
  very 
  fine-grained 
  

   near 
  the 
  contact, 
  and 
  is 
  certainly 
  younger 
  than 
  the 
  greenstone. 
  

   It 
  seems 
  to 
  have 
  been 
  intruded 
  along 
  the 
  wall 
  between 
  the 
  green- 
  

   stone 
  and 
  the 
  original 
  clastic, 
  which 
  was 
  in 
  contact 
  with 
  the 
  

   eruptive 
  greenstone 
  before 
  the 
  intrusion 
  of 
  the 
  granite. 
  A 
  narrow 
  

   band 
  of 
  this 
  clastic 
  may 
  now 
  be 
  seen 
  along 
  the 
  railway 
  about 
  \ 
  mile 
  

   east 
  of 
  the 
  present 
  contact 
  of 
  the 
  Whitson 
  Lake 
  eruptive 
  with 
  the 
  

   granite. 
  

  

  The 
  nickeliferous 
  pyrrhotite 
  is 
  intimately 
  intermingled 
  with 
  

   the 
  greenstone. 
  Chalcopyrite 
  is 
  present 
  in 
  very 
  much 
  smaller 
  

  

  e2 
  

  

  