﻿ADIRONDACK 
  MAGNETIC 
  IRON 
  ORES 
  III 
  

  

  massive 
  habit 
  with 
  the 
  regular 
  jointing 
  peculiar 
  to 
  deep 
  seated 
  

   intrusives. 
  While 
  there 
  are 
  no 
  supporting 
  evidences 
  of 
  inclusions 
  

   of 
  contact 
  effects, 
  it 
  is 
  regarded 
  as 
  igneous 
  and 
  probably 
  later 
  than 
  

   the 
  augite 
  gneiss. 
  

  

  A 
  second 
  type 
  of 
  granitic 
  gneiss, 
  related 
  to 
  the 
  preceding 
  in 
  

   mineral 
  character 
  but 
  possessing 
  a 
  thorough 
  cataclastic 
  structure, 
  

   was 
  found 
  on 
  Birch 
  hill 
  between 
  Lyon 
  Mountain 
  and 
  Upper 
  Cha- 
  

   teaugay 
  lake. 
  The 
  feldspar 
  consists 
  of 
  microperthite, 
  orthoclase 
  

   and 
  microcline, 
  all 
  of 
  which 
  have 
  been 
  crushed 
  and 
  finely 
  granu- 
  

   lated, 
  though 
  an 
  occasional 
  larger 
  crystal 
  particle 
  is 
  inclosed 
  in 
  the 
  

   crushed 
  materials. 
  The 
  quartz 
  is 
  drawn 
  out 
  into 
  thin 
  bands. 
  

   Much 
  magnetite 
  occurs 
  in 
  shreds 
  and 
  irregular 
  grains 
  distributed 
  

   through 
  the 
  mass 
  or 
  more 
  frequently 
  aggregated 
  along 
  parallel 
  

   lines 
  which 
  may 
  be 
  continuous 
  for 
  some 
  distance. 
  Except 
  for 
  a 
  little 
  

   secondary 
  biotite 
  there 
  are 
  no 
  ferromagnesian 
  minerals 
  present. 
  

  

  Hornblende 
  schist. 
  A 
  dark 
  hornblende 
  schistose 
  rock 
  is 
  occa- 
  

   sionally 
  found 
  in 
  small 
  patches 
  and 
  lenses 
  surrounded 
  by 
  the 
  augite 
  

   gneiss. 
  It 
  has 
  a 
  more 
  schistose 
  appearance 
  than 
  any 
  of 
  the 
  other 
  

   rocks 
  and 
  is 
  also 
  conspicuously 
  banded. 
  The 
  principal 
  mineral 
  is 
  

   dark 
  green 
  hornblende. 
  The 
  feldspar 
  includes 
  both 
  orthoclase 
  and 
  

   plagioclase 
  in 
  about 
  equal 
  proportions. 
  The 
  remaining 
  minerals 
  

   comprise 
  scapolite 
  and 
  titanite, 
  the 
  latter 
  constituting 
  at 
  times 
  

   fully 
  10 
  per 
  cent 
  of 
  the 
  mass, 
  and 
  small 
  quantities 
  of 
  augite, 
  biotite, 
  

   magnetite 
  and 
  apatite. 
  

  

  Lithologically 
  the 
  schist 
  is 
  quite 
  like 
  the 
  schists 
  that 
  accompany 
  

   the 
  series 
  of 
  sedimentary 
  gneisses 
  and 
  the 
  crystalline 
  limestones. 
  

   No 
  exposures 
  of 
  limestone 
  were 
  found, 
  but 
  in 
  limited 
  areas 
  like 
  

   those 
  at 
  Lyon 
  Mountain 
  it 
  is 
  often 
  absent. 
  At 
  the 
  Williams 
  pit 
  

   the 
  schist 
  forms 
  both 
  walls 
  of 
  the 
  deposit 
  as 
  a 
  comparatively 
  thin 
  

   band 
  that 
  is 
  intercalated 
  in 
  the 
  augite 
  gneiss 
  with 
  the 
  axis 
  of 
  

   extension 
  parallel 
  to 
  the 
  general 
  strike. 
  It 
  is 
  seamed 
  by 
  layers 
  of 
  

   lighter 
  colored 
  gneiss 
  and 
  shades 
  off 
  at 
  the 
  edges 
  into 
  the 
  augite 
  

   gneiss 
  through 
  a 
  gradual 
  exchange 
  of 
  the 
  hornblende 
  for 
  the 
  augite 
  

   and 
  the 
  appearance 
  of 
  microperthitic 
  feldspar. 
  On 
  the 
  hanging 
  

   side 
  of 
  the 
  deposit, 
  the 
  schist 
  incloses 
  a 
  seam 
  that 
  is 
  made 
  up 
  

   almost 
  entirely 
  of 
  garnet, 
  a 
  black, 
  nearly 
  opaque, 
  submetallic 
  variety, 
  

   evidently 
  high 
  in 
  iron. 
  The 
  same 
  schist 
  was 
  noticed 
  in 
  the 
  walls 
  at 
  

   the 
  Dickson 
  open 
  cut, 
  and 
  much 
  of 
  it 
  occurs 
  in 
  the 
  rock 
  dumps 
  at 
  

   Parkhurst 
  shaft 
  though 
  not 
  observed 
  there 
  in 
  place. 
  These 
  obser- 
  

   vations 
  indicate 
  that 
  a 
  considerable 
  mass 
  of 
  the 
  rock, 
  probably 
  

   in 
  interrupted 
  bands 
  or 
  lenses, 
  is 
  inclosed 
  by 
  the 
  augite 
  gneiss 
  in 
  

   proximity 
  to 
  the 
  ore 
  zone. 
  

  

  