﻿-48 
  ME. 
  T. 
  L. 
  WALXEE 
  ON 
  THE 
  [Feb. 
  1 
  897, 
  

  

  near 
  the 
  point 
  where 
  the 
  railway 
  enters 
  the 
  township 
  of 
  Rayside, 
  

   there 
  are 
  good 
  exposures 
  of 
  a 
  somewhat 
  coarse-grained 
  rock, 
  which 
  

   is 
  greenish 
  on 
  the 
  weathered 
  surface, 
  while 
  the 
  freshly-broken 
  

   surfaces 
  exposed 
  in 
  the 
  railway- 
  cuttings 
  are 
  nearly 
  black, 
  with 
  a 
  

   bluish 
  tint. 
  It 
  is 
  the 
  diorite 
  or 
  greenstone 
  of 
  the 
  prospectors, 
  

   which 
  the 
  microscope 
  shows 
  to 
  be 
  norite. 
  Hypersthene 
  forms 
  

   idiomorphic 
  crystals, 
  and 
  seems 
  to 
  have 
  been 
  the 
  first 
  of 
  the 
  essential 
  

   minerals 
  to 
  crystallize. 
  Sections 
  of 
  this 
  mineral 
  when 
  in 
  the 
  pris- 
  

   matic 
  zone 
  are 
  stoutly 
  rectangular, 
  while 
  sections 
  parallel 
  to 
  the 
  

   basis 
  are 
  octagonal 
  and 
  show 
  indistinct 
  prismatic 
  cleavage. 
  It 
  is 
  

   strongly 
  pleochroic 
  — 
  rose- 
  red, 
  bluish-grey 
  to 
  nearly 
  colourless. 
  The 
  

   crystals 
  of 
  hypersthene 
  are 
  generally 
  bordered 
  and 
  veined 
  with 
  

   bastite, 
  which 
  often 
  contains 
  small 
  grains 
  of 
  magnetite. 
  In 
  other 
  

   cases 
  the 
  alteration 
  has 
  proceeded 
  so 
  far 
  that 
  one 
  observes 
  rect- 
  

   angular 
  areas 
  of 
  bastite 
  which 
  contain 
  only 
  a 
  few 
  separated 
  grains 
  

   of 
  hypersthene. 
  Where 
  the 
  bastitic 
  alteration-products 
  border 
  on 
  

   plagioclase, 
  a 
  still 
  further 
  change 
  occurs, 
  in 
  that 
  bastitic 
  fibres 
  and 
  

   magnetite-grains 
  give 
  place 
  to 
  a 
  somewhat 
  compact, 
  strongly 
  

   pleochroic, 
  bluish-green 
  hornblende. 
  This 
  latter 
  change 
  does 
  not 
  

   occur 
  along 
  borders 
  between 
  bastitic 
  areas 
  and 
  biotite 
  or 
  magnetite. 
  

   The 
  felspar 
  seems 
  to 
  participate, 
  by 
  contributing 
  the 
  alumina 
  

   necessary 
  for 
  the 
  formation 
  of 
  green 
  hornblende. 
  

  

  Plagioclase 
  is 
  the 
  most 
  abundant 
  mineral. 
  The 
  crystals 
  are 
  

   xenomorphic 
  when 
  in 
  contact 
  with 
  hypersthene, 
  which 
  is 
  thus 
  seen 
  

   to 
  have 
  crystallized 
  earlier 
  than 
  the 
  plagioclase. 
  The 
  broadly- 
  

   twinned 
  plagioclase-crystals 
  are 
  from 
  two 
  to 
  three 
  times 
  as 
  long 
  as 
  

   broad, 
  and 
  even 
  in 
  the 
  thinnest 
  sections 
  are 
  brownish, 
  owing 
  to 
  the 
  

   presence 
  of 
  innumerable 
  dust-like 
  inclusions, 
  which 
  are 
  regarded 
  as 
  

   ilmenite, 
  and 
  are 
  very 
  characteristic 
  of 
  plagioclase 
  in 
  norites. 
  

   Besides 
  these 
  brown 
  inclusions, 
  too 
  small 
  to 
  admit 
  of 
  microscopic 
  

   determination, 
  there 
  are 
  colourless 
  needle-like 
  inclusions 
  which 
  form 
  

   a 
  network 
  of 
  three 
  parallel 
  systems. 
  It 
  is 
  probable 
  that 
  these 
  in- 
  

   clusions 
  are 
  parallel 
  to 
  the 
  three 
  edges 
  formed 
  by 
  the 
  pinacoidal 
  

   faces. 
  Measurements 
  of 
  extinction-angles 
  lead 
  to 
  the 
  conclusion 
  

   that 
  we 
  are 
  here 
  dealing 
  with 
  bytownite. 
  

  

  Augite 
  forms 
  occasional, 
  large, 
  irregularly-bounded 
  grains, 
  which 
  

   are 
  non-pleochroic, 
  and 
  xenomorphic 
  with 
  respect 
  to 
  hypersthene 
  

   and 
  plagioclase. 
  Inclusions 
  parallel 
  to 
  OP 
  give 
  the 
  appearance 
  

   of 
  basal 
  cleavage 
  when 
  examined 
  with 
  a 
  low 
  power. 
  

  

  Besides 
  the 
  above-mentioned 
  hornblende, 
  which 
  is 
  of 
  secondary 
  

   origin, 
  there 
  is 
  a 
  small 
  proportion 
  of 
  apparently 
  primary 
  nature. 
  

   It 
  never 
  occurs 
  alone 
  in 
  well-formed 
  crystals, 
  but 
  mostly 
  forms 
  

   horders 
  on 
  crystals 
  of 
  hypersthene 
  and 
  on 
  areas 
  of 
  bastite 
  derived 
  

   from 
  these. 
  This 
  hornblende 
  possesses 
  well-developed 
  cleavage, 
  

   definite 
  outline 
  when 
  bordering 
  on 
  felspar, 
  is 
  darker 
  than 
  the 
  

   secondary 
  hornblende, 
  and 
  is 
  compact 
  and 
  not 
  fibrous. 
  Much 
  

   might 
  be 
  said 
  in 
  favour 
  of 
  the 
  secondary 
  nature 
  of 
  this 
  hornblende, 
  

   where 
  it 
  could 
  be 
  regarded 
  as 
  the 
  final 
  product 
  of 
  the 
  alteration 
  

   represented 
  by 
  the 
  change 
  of 
  hypersthene 
  to 
  a 
  bastite-magnetite 
  

   aggregate, 
  this 
  to 
  bluish-green 
  hornblende 
  with 
  no 
  characteristic 
  

  

  