﻿Vol. 
  53.] 
  SUDBTJEY 
  NICKEL 
  DISTETCT 
  (CaKADA). 
  61 
  

  

  It 
  is 
  worthy 
  of 
  note 
  that 
  most 
  of 
  the 
  narrow 
  areas 
  of 
  nickeliferous 
  

   rocks 
  have 
  been 
  acted 
  upon 
  by 
  dynamic 
  metamorphism 
  with 
  com- 
  

   parative 
  ease, 
  and 
  as 
  a 
  result 
  the 
  original 
  unaltered 
  rock 
  is 
  seldom 
  

   found 
  in 
  the 
  smaller 
  eruptives. 
  The 
  original 
  rock 
  was 
  probably 
  a 
  

   massive 
  norite 
  or 
  gabbro, 
  which 
  was 
  changed 
  into 
  schistose 
  horn- 
  

   blende-rock. 
  This 
  is 
  seen 
  in 
  the 
  rocks 
  of 
  the 
  Stobie, 
  Travers, 
  and 
  

   Worthington 
  eruptives. 
  On 
  the 
  other 
  hand, 
  large 
  eruptives 
  such 
  

   as 
  the 
  two 
  first 
  described 
  have 
  retained 
  their 
  massive 
  structure 
  and 
  

   to 
  a 
  large 
  extent 
  their 
  pyroxene 
  content. 
  

  

  As 
  compared 
  with 
  the 
  Norwegian 
  nickeliferous 
  rocks, 
  the 
  Sudbury 
  

   rocks 
  are 
  decidedly 
  more 
  acid, 
  for 
  olivine, 
  which 
  is 
  a 
  frequent 
  con- 
  

   stituent 
  of 
  the 
  former, 
  has 
  never 
  been 
  detected 
  in 
  any 
  of 
  the 
  

   Sudbury 
  nickeliferous 
  rocks. 
  

  

  VI. 
  The 
  Youngee 
  Geanites. 
  

  

  We 
  must 
  now 
  refer 
  briefly 
  to 
  a 
  class 
  of 
  granites 
  which 
  are 
  younger 
  

   than 
  the 
  nickeliferous 
  rocks, 
  and 
  may 
  be 
  conveniently 
  spoken 
  of 
  

   as 
  ' 
  Younger 
  Granites.' 
  The 
  best 
  exposures 
  of 
  these 
  rocks 
  occur 
  

   on 
  the 
  main 
  line 
  of 
  the 
  Canadian 
  Pacific 
  Eailway, 
  about 
  2 
  miles 
  

   west 
  of 
  Murray 
  Mines. 
  The 
  nickel-bearing 
  rocks 
  are 
  there 
  cut 
  by 
  

   two 
  separate 
  eruptions 
  of 
  fine-grained, 
  pinkish 
  biotite-granite, 
  which 
  

   sends 
  off 
  apophyses 
  into 
  the 
  surrounding 
  greenstone. 
  The 
  wider 
  of 
  

   these 
  intrusions 
  is 
  about 
  100 
  yards 
  broad, 
  while 
  the 
  smaller 
  is 
  

   less 
  than 
  60 
  varus. 
  The 
  microscope 
  shows 
  that 
  quartz, 
  orthc 
  r1 
  

   plagioclase, 
  and 
  biotite 
  are 
  the 
  chief 
  constituents. 
  

  

  Where 
  the 
  rock 
  comes 
  into 
  contact 
  with 
  the 
  norite, 
  the 
  hyper- 
  

   sthene, 
  hornblende, 
  and 
  augite 
  of 
  the 
  latter 
  are 
  changed 
  to 
  fine 
  scaly 
  

   biotite, 
  while 
  the 
  well-formed 
  plagioclase 
  is 
  replaced 
  by 
  an 
  aggregate 
  

   of 
  granular 
  plagioclase, 
  epidote, 
  and 
  quartz. 
  

  

  Another 
  exposure 
  of 
  this 
  rock 
  occurs 
  immediately 
  south-east 
  of 
  

   Murray 
  Mines, 
  where 
  it 
  cuts 
  through 
  the 
  nickeliferous 
  greenstone, 
  

   sometimes 
  forming 
  apparent 
  inliers 
  in 
  the 
  same. 
  In 
  other 
  places 
  

   breccias 
  are 
  formed 
  by 
  the 
  inclusion 
  of 
  angular 
  fragments 
  of 
  green- 
  

   stone 
  in 
  a 
  groundmass 
  of 
  fine-grained 
  pinkish 
  granite. 
  

  

  It 
  appears 
  as 
  if 
  there 
  had 
  been 
  an 
  intrusion 
  of 
  this 
  granite 
  along 
  

   the 
  contact 
  between 
  the 
  nickel-bearing 
  eruptives 
  and 
  the 
  Huronian 
  

   rocks 
  south-east 
  of 
  them. 
  The 
  width 
  of 
  this 
  granitic 
  intrusion 
  is 
  

   over 
  \ 
  mile. 
  It 
  contains 
  numerous 
  inliers 
  of 
  greenstone. 
  A 
  narrow 
  

   strip 
  of 
  mica-schist 
  11 
  yards 
  wide 
  is 
  exposed 
  along 
  the 
  railway 
  

   on 
  the 
  south-eastern 
  border 
  of 
  the 
  granite. 
  The 
  schist 
  dips 
  at 
  

   very 
  high 
  angles, 
  and 
  doubtless 
  represents 
  the 
  rock 
  which 
  was 
  

   originally 
  in 
  contact 
  with 
  the 
  nickel-bearing 
  eruptive. 
  Similar 
  

   exposures 
  of 
  fine-grained 
  granite 
  are 
  observed 
  immediately 
  south 
  

   of 
  Elezard 
  Mine. 
  

  

  North 
  of 
  Copper 
  Cliff 
  Mine 
  there 
  is 
  a 
  large 
  area 
  of 
  coarse 
  

   gneissoid 
  granite, 
  which 
  the 
  late 
  Baron 
  v 
  F 
  Hon 
  considered 
  to 
  be 
  

   Laurentian. 
  It 
  is 
  essentially 
  the 
  same 
  1 
  that 
  exposed 
  east 
  of 
  

   Murray 
  Mines, 
  except 
  that 
  the 
  latter 
  has 
  been 
  so 
  crushed 
  as 
  to 
  

   present 
  a 
  much 
  finer 
  grain. 
  

  

  