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  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  chiefly 
  militate 
  against 
  the 
  return 
  of 
  empty 
  cars 
  and 
  the 
  haulage 
  of 
  

   supplies 
  for 
  the 
  mines. 
  

  

  Geology. 
  As 
  affecting 
  the 
  ore 
  bodies, 
  two 
  geological 
  series 
  are 
  

   of 
  chief 
  importance, 
  but 
  there 
  are 
  at 
  least 
  two 
  others 
  of 
  eruptive 
  

   rocks 
  which 
  also 
  concern 
  them. 
  Later 
  than 
  all 
  and 
  having 
  little 
  

   to 
  do 
  with 
  the 
  ores, 
  but 
  mentioned 
  so 
  as 
  to 
  complete 
  the 
  local 
  

   geology, 
  there 
  are 
  the 
  Paleozoic 
  sediments. 
  The 
  accompanying 
  

   columnar 
  statement 
  presents 
  all 
  the 
  formations 
  from 
  the 
  latest 
  

   above, 
  to 
  the 
  oldest 
  beneath. 
  

  

  Champlain 
  clays 
  

  

  Glacial 
  drift 
  

   " 
  Utica 
  slate 
  

  

  Trenton 
  limestone 
  

   Paleozoics 
  s 
  Chazy 
  limestone 
  

  

  Beekmantown 
  limestone 
  

  

  Potsdam 
  sandstone 
  

  

  Diabase 
  dikes 
  

  

  Gabbros, 
  dark, 
  basic 
  and 
  more 
  or 
  less 
  gneissoid. 
  In 
  

   the 
  mining 
  localities 
  of 
  uncertain 
  relation 
  to 
  

   the 
  syenites 
  

  

  Augite 
  syenites 
  and 
  related 
  types 
  more 
  or 
  less 
  gneissoid 
  

  

  Anorthosites 
  more 
  or 
  less 
  gneissoid 
  

  

  The 
  Grenville 
  series 
  of 
  metamorphosed 
  sediments, 
  

  

  limestones, 
  quartzites, 
  hornblende 
  schists 
  and 
  

  

  rusty 
  schistose 
  gneisses 
  

  

  Champlain 
  clays. 
  The 
  clays 
  appear 
  along 
  the 
  lake 
  shore 
  and 
  are 
  

  

  practically 
  limited 
  to 
  a 
  zone 
  a 
  hundred 
  feet 
  more 
  or 
  less 
  above 
  it. 
  

  

  They 
  have 
  no 
  bearing 
  upon 
  the 
  iron 
  industry. 
  

  

  Glacial 
  drift. 
  Under 
  this 
  term 
  is 
  embraced 
  the 
  morainal 
  

   materials, 
  sands 
  and 
  gravels, 
  which 
  beginning 
  higher 
  up 
  from 
  the 
  

   lake 
  than 
  the 
  Champlain 
  clays 
  mantle 
  all 
  the 
  surfaces. 
  Even 
  the 
  

   highest 
  peaks 
  are 
  not 
  free 
  from 
  boulders 
  and 
  the 
  rounded 
  cobbles 
  

   of 
  the 
  hard 
  resistant 
  Potsdam 
  quartzite 
  are 
  everywhere 
  through- 
  

   out 
  the 
  area. 
  Sometimes 
  the 
  drift 
  is 
  water 
  sorted 
  but 
  in 
  the 
  cases 
  

   which 
  especially 
  affect 
  the 
  mines 
  in 
  the 
  vicinity 
  of 
  Mineville 
  it 
  

   consists 
  of 
  heavy 
  boulders 
  and 
  sand. 
  In 
  sinking 
  the 
  Harmony 
  

   shafts 
  quite 
  200 
  feet 
  of 
  this 
  overlying 
  burden 
  were 
  penetrated 
  and 
  

   in 
  a 
  neighboring 
  bore 
  hole, 
  248 
  feet, 
  before 
  bed 
  rock 
  was 
  reached. 
  

   These 
  depths 
  were 
  encountered 
  on 
  the 
  side 
  of 
  the 
  present 
  valley 
  

   and 
  above 
  the 
  stream 
  bottom. 
  Under 
  these 
  circumstances 
  ore 
  

   bodies 
  can 
  only 
  be 
  located 
  by 
  means 
  of 
  a 
  magnetic 
  survey, 
  and 
  

   this 
  method 
  is 
  carried 
  out 
  by 
  the 
  companies 
  with 
  magnetometers 
  

  

  