﻿56 
  ME. 
  T. 
  1. 
  WALKER 
  ON 
  THE 
  [Feb. 
  1897, 
  

  

  While 
  engaged 
  as 
  an 
  assistant 
  on 
  the 
  Canadian 
  Geological 
  Survey 
  

   in 
  1890, 
  and 
  exploring 
  south 
  of 
  White 
  Water 
  Lake 
  with 
  a 
  view 
  to 
  

   determining 
  the 
  boundaries 
  of 
  the 
  eruptive, 
  I 
  first 
  observed 
  that 
  

   there 
  was 
  not 
  a 
  sharp 
  boundary 
  between 
  the 
  greenstone 
  and 
  the 
  

   granite 
  lying 
  north- 
  west 
  of 
  it, 
  since 
  there 
  appeared 
  to 
  be 
  everywhere 
  

   a 
  gradual 
  transition 
  from 
  the 
  one 
  to 
  the 
  other. 
  

  

  In 
  the 
  previous 
  pages 
  it 
  has 
  been 
  shown 
  that 
  such 
  transitions 
  

   occur 
  along 
  all 
  the 
  cross-sections 
  of 
  the 
  Whitson 
  Lake 
  eruptive. 
  The 
  

   variations 
  in 
  chemical 
  composition 
  of 
  these 
  rocks 
  are 
  illustrated 
  in 
  the 
  

   following 
  series 
  o 
  f 
  analyses 
  of 
  specimens 
  collected 
  along 
  the 
  Blezard 
  

   Mine 
  crossing. 
  The 
  specimens 
  range 
  from 
  south 
  to 
  north, 
  from 
  

   I 
  to 
  Y. 
  I 
  am 
  indebted 
  for 
  analysis 
  IV 
  to 
  Mr. 
  C. 
  B. 
  Fox, 
  M.A., 
  

   chemist 
  of 
  the 
  Iron 
  and 
  Steel 
  Company, 
  of 
  Hamilton, 
  Ontario 
  : 
  — 
  

  

  I. 
  II. 
  III. 
  IV. 
  V. 
  

  

  0/ 
  0/ 
  0/ 
  0/ 
  0/ 
  

  

  /o 
  /<> 
  /o 
  /o 
  /o 
  

  

  Si0 
  2 
  49-90 
  51-52 
  64-85 
  69-27 
  67'76 
  

  

  TiO., 
  1-47 
  1-39 
  0-78 
  0-46 
  

  

  P 
  2 
  5 
  017 
  010 
  0-24 
  006 
  0-19 
  

  

  A1 
  2 
  C 
  3 
  16-32 
  19-77 
  11'44 
  12-56 
  14-00 
  

  

  Fe 
  2 
  3 
  -47 
  2-94 
  289 
  

  

  FeO 
  13-54 
  677 
  6-02 
  4-51 
  5-18 
  

  

  CaO 
  6-58 
  8-16 
  3-49 
  1-44 
  4-28 
  

  

  MgO 
  6-22 
  6-49 
  1-60 
  091 
  1-00 
  

  

  MdO 
  trace 
  trace 
  trace 
  trace 
  trace 
  

  

  K 
  2-25 
  0-70 
  3-02 
  3'05 
  1-19 
  

  

  Na 
  2 
  1-82 
  2-66 
  392 
  3'12 
  5"22 
  

  

  H 
  2 
  0-76 
  1-68 
  0-78 
  0-76 
  101 
  

  

  Total 
  99-03 
  99-71 
  98-30 
  9935 
  100-29 
  

  

  Specific 
  gravity 
  = 
  3-026 
  2*832 
  2"788 
  2"724 
  2*709 
  

  

  Several 
  of 
  the 
  most 
  important 
  nickel-deposits 
  occur 
  along 
  the 
  

   south-eastern 
  border 
  of 
  the 
  Whitson 
  Lake 
  eruptive 
  ; 
  among 
  others 
  

   the 
  Blezard, 
  Murray, 
  Little 
  Stobie, 
  and 
  Lady 
  M 
  c 
  Donald 
  mines. 
  

  

  (iii) 
  The 
  Windy 
  Lake 
  Eruptive. 
  

  

  This 
  eruptive 
  is 
  situated 
  about 
  25 
  miles 
  north-west 
  of 
  Sudbury, 
  

   and 
  is 
  known 
  to 
  extend 
  from 
  the 
  township 
  of 
  Lavack 
  south-west 
  to 
  

   the 
  township 
  of 
  Trill, 
  a 
  distance 
  of 
  20 
  miles, 
  though 
  its 
  total 
  length 
  

   is 
  probably 
  much 
  greater. 
  Exceptional 
  opportunity 
  is 
  afforded 
  for 
  

   the 
  examination 
  of 
  this 
  eruptive 
  by 
  the 
  cuttings 
  of 
  the 
  Canadian 
  

   Pacific 
  Railway 
  near 
  Windy 
  Lake, 
  where 
  the 
  rock 
  extends 
  over 
  a 
  

   width 
  of 
  nearly 
  4 
  miles. 
  Onaping 
  Station 
  is 
  situated 
  near 
  the 
  

   south-eastern 
  border 
  of 
  the 
  area. 
  

  

  About 
  3| 
  miles 
  west 
  of 
  Onaping 
  Station 
  the 
  railway 
  passes 
  

   through 
  a 
  ridge 
  of 
  greyish 
  to 
  pinkish, 
  heavily-bedded 
  gneiss, 
  which 
  

   was 
  described 
  at 
  the 
  beginning 
  of 
  this 
  paper 
  (p. 
  42). 
  On 
  travelling 
  

   eastward 
  a 
  few 
  hundred 
  feet 
  along 
  the 
  low 
  margins 
  of 
  Windy 
  Lake 
  

   no 
  rocks 
  are 
  observed, 
  but 
  a 
  little 
  farther 
  east 
  there 
  are 
  exposures 
  

   of 
  a 
  medium-grained 
  rock, 
  in 
  which 
  the 
  unaided 
  eye 
  distinguishes 
  

   a 
  black 
  mineral 
  occurring 
  as 
  separate 
  grains, 
  and 
  a 
  much 
  more 
  

  

  