﻿GEOLOGY 
  OF 
  THOUSAND 
  ISLANDS 
  REGION 
  35 
  

  

  gneiss 
  " 
  with 
  its 
  characteristic 
  yellowish 
  tinge 
  on 
  weathered 
  sur- 
  

   faces, 
  is 
  but 
  sparingly 
  present 
  in 
  our 
  area 
  here. 
  In 
  the 
  district 
  

   east 
  of 
  Redwood 
  it 
  occurs 
  somewhat, 
  as 
  it 
  does 
  also 
  to 
  the 
  north- 
  

   ward 
  of 
  Theresa. 
  It 
  is 
  a 
  quartzose 
  gneiss, 
  usually 
  containing 
  the 
  

   mineral 
  '' 
  sillimanite 
  " 
  and 
  holding 
  pyrite 
  in 
  ^quantity, 
  the 
  easy 
  de- 
  

   composition 
  of 
  which 
  is 
  chiefly 
  accountable 
  for 
  the 
  weakness 
  and 
  

   the 
  color 
  stain 
  of 
  the 
  rock. 
  

  

  There 
  are 
  reddish, 
  acid 
  gneisses 
  which, 
  so 
  far 
  as 
  composition 
  

   goes 
  might 
  be 
  either 
  original 
  granites, 
  or 
  shaly 
  sandstones. 
  There 
  

   are 
  black 
  and 
  white 
  gneisses^ 
  which 
  are 
  feldspar-pyroxene-quartz 
  

   gneisses. 
  There 
  are 
  very 
  granular, 
  dark 
  reddish, 
  weak, 
  microper- 
  

   thitic 
  feldspar-hornblende 
  gneisses; 
  gray, 
  f 
  eld-spar-hornblende 
  

   gneisses, 
  holding 
  much 
  pyrite 
  and 
  titanite; 
  there 
  are 
  leaf 
  -quartz 
  

   gneisses, 
  the 
  quartz 
  in 
  coarse 
  spindles 
  or 
  lenses, 
  and 
  with 
  little 
  

   other 
  than 
  feldspar 
  in 
  addition; 
  evenly 
  granular, 
  white, 
  spotted 
  

   gneisses 
  which 
  are 
  microperthite-quartz-hornblende 
  rocks; 
  garneti- 
  

   ferous, 
  quartz-biotite 
  gneisses, 
  with 
  but 
  little 
  feldspar 
  and 
  a 
  lot 
  of 
  

   pyrite; 
  quartz-feldspar-phlogopite 
  gneisses 
  with 
  graphite; 
  gneisses 
  

   which 
  somewhat 
  suggest 
  metamorphosed 
  volcanic 
  tuffs, 
  though 
  in 
  

   no 
  case 
  has 
  it 
  been 
  possible 
  to 
  demonstrate 
  such 
  an 
  origin 
  for 
  them. 
  

   Many 
  of 
  the 
  rocks 
  contain 
  calcite, 
  which 
  at 
  times 
  has 
  resulted 
  

   from 
  alteration 
  and 
  at 
  times 
  suggests 
  itself 
  as 
  an 
  original 
  constit- 
  

   uent. 
  Graphite 
  is 
  a 
  frequent 
  mineral 
  in 
  many 
  of 
  the 
  schists. 
  

  

  Nowhere 
  in 
  the 
  district 
  has 
  a 
  rock 
  been 
  found 
  which 
  at 
  all 
  sug- 
  

   gests 
  the 
  greenstones 
  of 
  the 
  Keewatin 
  formation. 
  

  

  Belts 
  of 
  badly 
  altered 
  rock, 
  considerably 
  impregnated 
  with 
  iron, 
  

   so 
  as 
  to 
  constitute 
  lean 
  iron 
  ore, 
  occur 
  within 
  the 
  Grenville 
  schist 
  

   belts, 
  striking 
  with 
  the 
  belt 
  and 
  apparently 
  behaving 
  like 
  an 
  in- 
  

   tegral 
  part 
  of 
  the 
  series. 
  Fragments 
  of 
  one 
  such 
  belt 
  are 
  found 
  

   in 
  the 
  granite 
  of 
  the 
  Alexandria 
  bathylith 
  near 
  Cranberry 
  creek, 
  

   and 
  a 
  prominent 
  belt 
  occurs 
  east 
  of 
  Redwood, 
  especially 
  along 
  the 
  

   north 
  side 
  of 
  Millsite 
  lake. 
  The 
  rock 
  is 
  exceedingly 
  weak, 
  earthy 
  

   looking, 
  either 
  red, 
  or 
  yellow 
  brown 
  in 
  color, 
  and 
  has 
  a 
  consider- 
  

   able 
  local 
  use 
  for 
  road 
  metal. 
  It 
  is 
  so 
  thoroughly 
  altered 
  that 
  it 
  is 
  

   almost 
  impossible 
  to 
  get 
  any 
  clear 
  notion 
  of 
  its 
  original 
  character 
  

   being 
  simply 
  a 
  mass 
  of 
  clayey, 
  alteration 
  products, 
  with 
  consider- 
  

   able 
  calcite, 
  and 
  the 
  whole 
  impregnated 
  with 
  hydrated 
  iron 
  oxid, 
  

   chiefly 
  the 
  red 
  oxid. 
  There 
  are 
  fresher 
  streaks 
  and 
  bunches 
  here 
  

   and 
  there 
  which 
  appear 
  to 
  be 
  granite 
  gneiss. 
  None 
  of 
  the 
  so 
  

   called 
  " 
  serpentine 
  " 
  rock, 
  which 
  is 
  generally 
  associated 
  with 
  the 
  

   similar, 
  but 
  richer, 
  belt 
  of 
  iron 
  ore 
  which 
  runs 
  through 
  Antwerp 
  

  

  2 
  

  

  