﻿ADIRONDACK 
  MAGNETIC 
  IRON 
  ORES 
  1 
  25 
  

  

  name 
  from 
  their 
  extensive 
  occurrence 
  along 
  the 
  Saranac 
  river 
  in 
  

   this 
  section. 
  

  

  In 
  his 
  report 
  " 
  Geology 
  of 
  Clinton 
  County," 
  Cushing 
  describes 
  as 
  

   belonging 
  to 
  a 
  separate 
  type, 
  a 
  silicious 
  gneiss, 
  resembling 
  quartzite 
  

   in 
  appearance, 
  but 
  composed 
  of 
  microcline 
  and 
  quartz, 
  with 
  garnet 
  

   and 
  a 
  mineral 
  that 
  corresponds 
  optically 
  to 
  sillimanite. 
  It 
  occurs 
  

   along 
  Trout 
  brook 
  which 
  enters 
  the 
  Saranac 
  at 
  Russia. 
  From 
  its 
  

   composition 
  he 
  is 
  inclined 
  to 
  consider 
  the 
  rock 
  a 
  sedimentary 
  

   derivative 
  and 
  he 
  further 
  suggests 
  that 
  there 
  may 
  be 
  a 
  belt 
  of 
  

   related 
  gneisses 
  and 
  crystalline 
  limestone 
  within 
  the 
  drift-covered 
  

   valley. 
  The 
  exposures 
  are 
  insufficient 
  to 
  establish 
  the 
  extent 
  of 
  

   the 
  sedimentary 
  or 
  Grenville 
  rocks, 
  but 
  it 
  is 
  probable 
  that 
  such 
  a 
  

   belt 
  exists. 
  Further 
  evidence 
  confirming 
  this 
  view 
  was 
  found 
  by 
  

   the 
  writer 
  near 
  Clayburg 
  where 
  a 
  biotite 
  schist 
  is 
  exposed 
  along 
  

   the 
  west 
  bank 
  of 
  the 
  Saranac 
  river. 
  The 
  schist 
  has 
  been 
  injected 
  

   by 
  granitic 
  materials, 
  though 
  its 
  characters 
  are 
  plainly 
  those 
  of 
  

   the 
  Grenville 
  series, 
  shown 
  by 
  its 
  crumbling 
  well 
  foliated 
  texture, 
  

   pyritic 
  inclusions 
  and 
  variation 
  of 
  com/position 
  across 
  the 
  strike. 
  

  

  Small 
  areas 
  of 
  gabbro 
  are 
  found 
  at 
  two 
  localities 
  in 
  the 
  district. 
  

   The 
  largest 
  exposure 
  is 
  just 
  north 
  of 
  Clayburg 
  and 
  is 
  about 
  50 
  

   yards 
  wide; 
  the 
  second 
  outcrop 
  is 
  west 
  of 
  Russia 
  on 
  True 
  brook. 
  

   They 
  occur 
  as 
  dike 
  intrusions 
  in 
  the 
  Saranac 
  gneisses. 
  

  

  Diabase 
  dikes 
  are 
  numerous. 
  Cushing 
  has 
  listed 
  26 
  within 
  the 
  

   townships 
  of 
  Saranac 
  and 
  Black 
  Brook 
  and 
  several 
  more 
  occur 
  in 
  

   the 
  mines 
  that 
  have 
  not 
  been 
  recorded. 
  They 
  are 
  the 
  latest 
  of 
  the 
  

   recognizable 
  igneous 
  rocks. 
  

  

  Of 
  the 
  sedimentary 
  rocks 
  the 
  Potsdam 
  sandstone 
  composes 
  a 
  

   part 
  of 
  the 
  surface 
  geology 
  of 
  the 
  district, 
  occupying 
  a 
  large 
  area 
  

   in 
  Saranac 
  township 
  east 
  of 
  the 
  river. 
  It 
  is 
  not 
  exposed 
  

   anywhere 
  in 
  the 
  vicinity 
  of 
  the 
  ore 
  bodies. 
  

  

  Averill 
  mine. 
  Near 
  Dannemora 
  village 
  are 
  the 
  Averill, 
  Ellis, 
  

   Fairbanks 
  and 
  Dannemora 
  mines, 
  all 
  of 
  small 
  size. 
  They 
  lie 
  on 
  the 
  

   slopes 
  of 
  the 
  high 
  ridge 
  which 
  forms 
  the 
  north 
  side 
  of 
  the 
  Saranac 
  

   valley 
  and 
  of 
  which 
  Dannemora 
  mountain 
  marks 
  the 
  culmination 
  

   in 
  this 
  part. 
  

  

  The 
  Averill 
  mine 
  is 
  the 
  largest 
  of 
  the 
  group. 
  The 
  ore 
  body 
  is 
  

   first 
  encountered 
  a 
  few 
  hundred 
  feet 
  southwest 
  of 
  the 
  State 
  Prison 
  

   and 
  can 
  be 
  traced 
  in 
  a 
  northerly 
  direction 
  for 
  1000 
  feet. 
  It 
  is 
  

   inclosed 
  in 
  a 
  basic 
  hornblende-biotite 
  gneiss, 
  the 
  ore 
  itself 
  consisting 
  

   of 
  streaks 
  and 
  bands 
  of 
  magnetite 
  alternating 
  with 
  the 
  materials 
  

   of 
  the 
  wall 
  rock. 
  The 
  latter 
  is 
  cut 
  by 
  reddish 
  granite 
  of 
  which 
  

   there 
  is 
  a 
  large 
  exposure 
  on 
  the 
  hill 
  back 
  of 
  the 
  prison 
  that 
  has 
  

  

  