﻿54 
  ME. 
  T. 
  L. 
  WALKEE 
  ON 
  THE 
  [Feb. 
  1 
  .89 
  f 
  r 
  

  

  Station, 
  the 
  slate 
  has 
  been 
  so 
  altered 
  by 
  the 
  eruptive 
  as 
  to 
  lose 
  it& 
  

   schistosity 
  and 
  to 
  resemble 
  the 
  ' 
  hornf 
  els 
  ' 
  so 
  commonly 
  produced 
  by 
  

   granite 
  when 
  in 
  contact 
  with 
  slate. 
  This 
  rock 
  is 
  shown 
  by 
  the 
  

   microscope 
  to 
  be 
  composed 
  of 
  fine 
  scales 
  of 
  biotite 
  and 
  muscovite 
  and 
  

   grains 
  of 
  quartz. 
  The 
  quartz-grains 
  are 
  bounded 
  by 
  polyhedral 
  

   outlines, 
  so 
  as 
  to 
  produce 
  the 
  ' 
  pavement 
  '-structure 
  which 
  is 
  so- 
  

   characteristic 
  for 
  contact-products. 
  Eoundish 
  mica-scales 
  are 
  

   frequently 
  included 
  in 
  the 
  quartz-grains. 
  These 
  microscopic 
  struc- 
  

   tures 
  confirm 
  the 
  contact 
  nature 
  of 
  the 
  rock. 
  Calcite-grains 
  are 
  so- 
  

   common 
  that 
  the 
  rock-powder 
  effervesces 
  briskly 
  with 
  cold 
  hydro- 
  

   chloric 
  acid. 
  

  

  There 
  are 
  numerous 
  inclusions 
  of 
  quartzose 
  fragments 
  in 
  the 
  

   eruptive 
  near 
  the 
  junction. 
  The 
  presence 
  of 
  these 
  quartzite-inclusions 
  

   in 
  the 
  eruptive 
  indicates 
  that 
  it 
  has 
  broken 
  through 
  quartzitic 
  strata, 
  

   which 
  consequently 
  underlie 
  the 
  slates 
  at 
  present 
  observed 
  in 
  contact 
  

   with 
  the 
  granite. 
  

  

  j3. 
  Exposures 
  north 
  of 
  Blezard 
  Mine. 
  

  

  The 
  south-eastern 
  contact 
  is 
  only 
  a 
  short 
  distance 
  south 
  of 
  

   Blezard 
  Mine. 
  The 
  rocks 
  are 
  well 
  exposed 
  along 
  the 
  road 
  north 
  

   of 
  the 
  mine, 
  while 
  excellent 
  opportunity 
  is 
  afforded 
  for 
  geological 
  

   examination 
  by 
  the 
  rocky 
  shores 
  and 
  islands 
  of 
  Whitson 
  Lake. 
  The 
  

   rocks 
  of 
  this 
  cross-section 
  of 
  the 
  Whitson 
  Lake 
  eruptive 
  are 
  quite 
  

   similar 
  to 
  those 
  studied 
  in 
  the 
  previous 
  one 
  along 
  the 
  main 
  line 
  of" 
  

   the 
  Canadian 
  Pacific 
  Railway. 
  

  

  The 
  rock 
  a 
  short 
  distance 
  north 
  of 
  the 
  mine 
  is 
  almost 
  identical 
  

   with 
  the 
  type-rock 
  of 
  the 
  last 
  series. 
  It 
  is 
  dark, 
  and 
  of 
  medium 
  

   texture. 
  The 
  freshly-broken 
  surface 
  shows 
  a 
  few 
  scales 
  of 
  biotite. 
  

  

  Specimens 
  collected 
  200 
  yards 
  south-west 
  of 
  the 
  mine 
  along 
  the 
  

   railway 
  show 
  that 
  the 
  rock 
  has 
  undergone 
  considerable 
  alteration. 
  

   The 
  original 
  bisilicates 
  and 
  plagioclase 
  have 
  been 
  replaced 
  by 
  

   secondary 
  hornblende 
  and 
  irregular 
  water- 
  clear 
  grains 
  of 
  plagioclase, 
  

   which 
  are 
  generally 
  accompanied 
  by 
  small 
  grains 
  of 
  quartz. 
  

  

  Northward 
  from 
  Blezard 
  Mine 
  the 
  rocks 
  show 
  an 
  increase 
  in 
  

   acidity 
  and 
  alteration. 
  By 
  canoe 
  one 
  may 
  visit 
  the 
  shores 
  and 
  

   islands 
  of 
  Whitson 
  Lake, 
  where 
  further 
  changes 
  are 
  observed. 
  On 
  

   an 
  island 
  about 
  \ 
  mile 
  south 
  of 
  the 
  narrows 
  the 
  rock 
  begins 
  to 
  

   show 
  a 
  granitic 
  appearance, 
  the 
  quantity 
  of 
  quartz 
  is 
  much 
  larger, 
  

   brown 
  scaly 
  biotite 
  and 
  a 
  little 
  secondary 
  hornblende 
  represent 
  the 
  

   bisilicates, 
  while 
  untwinned 
  orthoclase-felspar 
  is 
  present 
  in 
  about 
  

   equal 
  quantity 
  with 
  the 
  narrowly-twinned 
  plagioclase. 
  

  

  Areas 
  of 
  secondary 
  hornblende 
  generally 
  extinguish 
  more 
  or 
  less 
  

   distinctly 
  in 
  two 
  portions, 
  but 
  in 
  sections 
  of 
  the 
  above 
  rock 
  this 
  

   manner 
  of 
  extinction 
  is 
  very 
  plain. 
  Moreover, 
  in 
  some 
  cases 
  horn- 
  

   blende 
  twinned 
  polysynthetically 
  on 
  oo 
  3? 
  oo 
  is 
  connected 
  with 
  these 
  

   areas, 
  and 
  one 
  part 
  of 
  the 
  hornblende-mosaic 
  extinguishes 
  with 
  one 
  

   series 
  of 
  twinning-lamellse, 
  while 
  the 
  other 
  part 
  of 
  the 
  mosaic 
  

   extinguishes 
  with 
  the 
  alternate 
  series 
  of 
  twinning-lamellse. 
  This 
  

   proves 
  that 
  the 
  hornblende 
  of 
  the 
  mosaic 
  is 
  oriented 
  in 
  the 
  position 
  

   for 
  twinning 
  on 
  oo 
  3? 
  oo. 
  It 
  differs, 
  however, 
  from 
  the 
  ordinary 
  

  

  