﻿24 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Adirondacks. 
  This 
  is 
  attributed 
  to 
  the 
  more 
  thorough 
  explora- 
  

   tion 
  of 
  the 
  outer 
  areas 
  owing 
  to 
  the 
  advantages 
  they 
  afford 
  in 
  

   regard 
  to 
  accessibility 
  for 
  prospecting 
  and 
  transport 
  of 
  the 
  ore 
  to 
  

   the 
  market. 
  No 
  doubt 
  the 
  explanation 
  is 
  a 
  reasonable 
  one 
  and 
  

   entitled 
  to 
  serious 
  consideration. 
  But 
  it 
  would 
  seem 
  not 
  improb- 
  

   able 
  that 
  there 
  is 
  an 
  underlying 
  geological 
  basis 
  for 
  the 
  gen- 
  

   eral 
  distribution 
  of 
  the 
  occurrences 
  that 
  may 
  be 
  brought 
  out 
  

   clearly 
  when 
  the 
  region 
  is 
  mapped 
  in 
  detail. 
  The 
  present 
  study 
  

   has 
  not 
  been 
  extended 
  beyond 
  the 
  limits 
  of 
  the 
  ore-bearing 
  dis- 
  

   tricts. 
  The 
  interior 
  of 
  the 
  Adirondacks 
  is 
  occupied 
  in 
  part 
  by 
  the 
  

   great 
  anorthosite 
  mass, 
  within 
  which 
  the 
  ores 
  are 
  all 
  titaniferous. 
  

   Of 
  the 
  extensive 
  region 
  to 
  the 
  west 
  and 
  south 
  of 
  this 
  area 
  to 
  near 
  

   the 
  Adirondack 
  borders 
  little 
  is 
  known 
  as 
  yet 
  concerning 
  its 
  

   geology. 
  

  

  By 
  far 
  the 
  greater 
  number 
  of 
  mines 
  that 
  have 
  been 
  worked, 
  

   including 
  all 
  the 
  important 
  ores, 
  are 
  restricted 
  to 
  a 
  few 
  districts 
  

   of 
  comparatively 
  limited 
  area. 
  The 
  total 
  surface 
  embraced 
  within 
  

   these 
  districts 
  constitutes 
  but 
  a 
  very 
  small 
  portion 
  of 
  the 
  whole 
  

   region. 
  It 
  is 
  probable 
  that 
  future 
  exploration 
  when 
  extended 
  

   into 
  the 
  outlying 
  areas 
  will 
  result 
  in 
  the 
  addition 
  of 
  new 
  deposits 
  

   to 
  the 
  list; 
  but 
  it 
  can 
  hardly 
  be 
  expected 
  that 
  the 
  discoveries 
  will 
  

   compare 
  in 
  importance 
  with 
  those 
  already 
  made. 
  The 
  favorable 
  

   ground 
  for 
  development 
  was 
  sought 
  out 
  by 
  the 
  early 
  prospectors 
  

   who 
  seem 
  to 
  have 
  penetrated 
  into 
  the 
  most 
  remote 
  parts 
  in 
  their 
  

   search 
  and 
  to 
  have 
  made 
  good 
  use 
  of 
  the 
  dip 
  needle 
  and 
  compass, 
  

   by 
  which 
  the 
  location 
  of 
  highly 
  magnetic 
  bodies 
  like 
  these 
  is 
  a 
  

   comparatively 
  easy 
  matter. 
  

  

  Character 
  of 
  the 
  ores 
  

  

  The 
  ores 
  show 
  great 
  variation 
  in 
  their 
  mineral 
  and 
  chemical 
  

   composition. 
  They 
  range 
  from 
  impure 
  lean 
  varieties 
  consisting 
  of 
  

   magnetite 
  intermixed 
  with 
  the 
  constituents 
  of 
  the 
  wall 
  rocks, 
  such 
  

   as 
  quartz, 
  feldspar, 
  pyroxene, 
  hornblende 
  etc., 
  to 
  those 
  made 
  up 
  of 
  

   practically 
  pure 
  magnetite. 
  The 
  richest 
  average 
  from 
  60 
  to 
  70 
  per 
  

   cent 
  iron. 
  They 
  have 
  been 
  obtained 
  principally 
  from 
  the 
  Mineville 
  

   district, 
  where 
  some 
  large 
  bodies 
  have 
  averaged 
  60 
  to 
  65 
  per 
  cent 
  

   iron 
  and 
  have 
  afforded 
  considerable 
  quantities 
  assaying 
  above 
  65 
  

   per 
  cent 
  and 
  even 
  approaching 
  closely 
  the 
  theoretical 
  limit 
  for 
  

   magnetite 
  which 
  is 
  72.4 
  per 
  cent. 
  The 
  Hammond 
  ville, 
  Arnold 
  

   hill 
  and 
  many 
  other 
  mines 
  have 
  yielded 
  ores 
  with 
  50 
  to 
  60 
  per 
  cent 
  

   iron. 
  The 
  magnetites 
  that 
  carry 
  less 
  than 
  about 
  50 
  per 
  cent 
  iron 
  

  

  