﻿^°1« 
  53'] 
  SUDBTTRY 
  NICKEL 
  D1STEICT 
  ( 
  CANADA). 
  45 
  

  

  (iii) 
  Phyllite. 
  

  

  This 
  rock 
  is 
  very 
  closely 
  associated 
  with 
  the 
  mica-schists, 
  and 
  

   may 
  be 
  examined 
  in 
  the 
  railway-cuttings 
  3 
  miles 
  east 
  of 
  Worth- 
  

   ington 
  Station. 
  The 
  rock 
  dips 
  at 
  high 
  angles, 
  and 
  is 
  purple-brown 
  

   in 
  colour. 
  On 
  the 
  cleavage-surfaces 
  small 
  yellowish-brown 
  specks 
  

   are 
  observed 
  which 
  the 
  microscope 
  shows 
  to 
  be 
  sagenitic 
  aggregates 
  

   of 
  rutile-crystals 
  : 
  these 
  are 
  fairly 
  transparent, 
  and 
  so 
  large 
  as 
  to 
  

   give 
  polarization-colours 
  resembling 
  those 
  of 
  zircon. 
  

  

  (iv) 
  Clay-Slates. 
  

  

  These 
  constitute 
  an 
  important 
  member 
  of 
  the 
  Huronian 
  complex. 
  

   They 
  may 
  be 
  examined 
  J 
  mile 
  west 
  of 
  Rayside 
  Station, 
  and 
  also 
  a 
  

   short 
  distance 
  north 
  of 
  White 
  Water 
  Lake. 
  In 
  the 
  former 
  place 
  

   they 
  are 
  in 
  contact 
  with 
  the 
  nickel-bearing 
  rocks, 
  and 
  close 
  to 
  the 
  

   junction 
  the 
  schistosity 
  has 
  quite 
  disappeared. 
  They 
  are 
  ashen- 
  

   grey, 
  drab 
  to 
  nearly 
  black 
  in 
  colour, 
  and 
  probably 
  represent 
  detritus 
  

   deposited 
  in 
  the 
  deeper 
  seas 
  of 
  the 
  Huronian 
  period. 
  

  

  (v) 
  Volcanic 
  Breccia. 
  

  

  The 
  western 
  portion 
  of 
  the 
  Huronian 
  belt 
  in 
  the 
  Sudbury 
  district 
  

   is 
  occupied 
  by 
  a 
  trough 
  which 
  is 
  composed 
  of 
  the 
  younger 
  Huronian 
  

   rocks. 
  This 
  trough 
  extends 
  nearly 
  from 
  Lake 
  Wahnapitae 
  south- 
  

   westward 
  to 
  the 
  township 
  of 
  Trill, 
  a 
  distance 
  of 
  over 
  30 
  miles. 
  

   The 
  greatest 
  width 
  is 
  a 
  little 
  over 
  8 
  miles. 
  The 
  central 
  part 
  of 
  the 
  

   trough 
  is 
  occupied 
  by 
  evenly-grained 
  grauwacke, 
  while 
  the 
  margin 
  

   is 
  composed 
  of 
  a 
  highly-altered 
  volcanic 
  breccia. 
  One 
  of 
  the 
  most 
  

   accessible 
  exposures 
  of 
  this 
  breccia 
  is 
  on 
  the 
  northern 
  shore 
  of 
  

   Whitson 
  Lake, 
  where 
  it 
  is 
  in 
  contact 
  with 
  the 
  nickel-bearing 
  

   eruptive. 
  The 
  colour 
  is 
  ashen-grey, 
  the 
  stratification 
  distinct, 
  

   though 
  interrupted 
  and 
  lumpy, 
  and 
  the 
  strike 
  is 
  N. 
  70° 
  E. 
  The 
  

   microscope 
  discloses 
  the 
  breccia-structure. 
  The 
  volcanic 
  fragments 
  

   are 
  quite 
  angular, 
  and 
  sometimes 
  show 
  flow-structure, 
  though 
  they 
  

   have 
  been 
  generally 
  replaced 
  by 
  aggregates 
  of 
  secondary 
  minerals 
  

   — 
  chlorite, 
  quartz, 
  felspar, 
  muscovite, 
  and 
  calcite. 
  Glass 
  could 
  be 
  

   seen 
  neither 
  in 
  the 
  fragments 
  nor 
  in 
  the 
  matrix. 
  An 
  analysis 
  of 
  

   the 
  breccia 
  north 
  of 
  Whitson 
  Lake 
  gave 
  the 
  following 
  results 
  : 
  — 
  

  

  Si0 
  2 
  59-93%. 
  

  

  A1 
  2 
  3 
  12-12 
  „ 
  

  

  FeO 
  10-56 
  „ 
  

  

  MnO 
  trace 
  

  

  CaO 
  4-49 
  „ 
  

  

  MgO 
  5-19 
  „ 
  

  

  Na 
  2 
  3-80 
  „ 
  

  

  K 
  2 
  . 
  0-97 
  „ 
  

  

  Loss 
  by 
  ignition 
  .. 
  . 
  157 
  ,, 
  

  

  Total 
  9863 
  „ 
  

  

  There 
  are 
  also 
  good 
  exposures 
  of 
  this 
  rock 
  along 
  the 
  north-western 
  

   border, 
  about 
  1| 
  mile 
  south-east 
  of 
  Onaping 
  Station. 
  

  

  