﻿114 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  ticularly 
  noticeable 
  on 
  weathered 
  outcrops 
  where 
  the 
  narrow 
  bands 
  

   of 
  magnetite 
  stand 
  out 
  in 
  relief 
  like 
  small 
  veins. 
  The 
  magnetite 
  

   occurs 
  in 
  granular 
  particles, 
  or 
  irregular 
  masses 
  made 
  up 
  of 
  many 
  

   grains, 
  with 
  rarely 
  any 
  tendency 
  toward 
  crystal 
  development. 
  

   When 
  specimens 
  are 
  examined 
  under 
  the 
  microscope 
  the 
  particles 
  

   are 
  seen 
  to 
  occupy 
  the 
  interspaces, 
  occurring 
  on 
  the 
  borders 
  of 
  the 
  

   other 
  minerals 
  or 
  completely 
  inclosing 
  them, 
  a 
  relation 
  which 
  

   suggests 
  that 
  they 
  have 
  been 
  the 
  last 
  to 
  form. 
  A 
  few 
  small 
  crystals 
  

   of 
  magnetite 
  having 
  octahedral 
  boundaries 
  are 
  generally 
  observed 
  

   in 
  the 
  slides 
  and 
  are 
  doubtless 
  of 
  an 
  earlier 
  generation. 
  In 
  the 
  

   average 
  ore 
  there 
  are 
  about 
  equal 
  proportions 
  of 
  magnetite 
  and 
  gan- 
  

   gue 
  minerals. 
  Among 
  the 
  less 
  important 
  components 
  of 
  the 
  ore 
  

   may 
  be 
  mentioned 
  apatite, 
  titanite, 
  zircon 
  and 
  pyrite; 
  they 
  con- 
  

   stitute 
  only 
  a 
  minute 
  percentage 
  of 
  the 
  mass 
  as 
  shown 
  by 
  the 
  

   analyses. 
  At 
  the 
  Williams 
  pit, 
  a 
  black 
  almost 
  opaque 
  garnet 
  was 
  

   found 
  in 
  the 
  form 
  of 
  rounded 
  grains 
  mingled 
  with 
  magnetite, 
  near 
  

   the 
  contact 
  of 
  the 
  ore 
  body 
  and 
  the 
  schist 
  of 
  the 
  hanging 
  wall; 
  

   this 
  mineral 
  has 
  not 
  been 
  observed 
  elsewhere. 
  

  

  Pegmatite 
  is 
  abundant 
  in 
  the 
  ore 
  bodies. 
  The 
  common 
  variety 
  

   has 
  a 
  reddish 
  color 
  and 
  is 
  composed 
  of 
  alkali 
  feldspar, 
  augite, 
  

   quartz 
  and 
  magnetite, 
  resembling 
  the 
  augite 
  gneiss 
  except 
  for 
  its 
  

   coarser 
  more 
  massive 
  texture. 
  Occasionally 
  it 
  contains 
  a 
  sufficient 
  

   quantity 
  of 
  magnetite 
  to 
  be 
  considered 
  an 
  ore. 
  Another 
  variety 
  

   of 
  pegmatite 
  is 
  made 
  up 
  of 
  deep 
  red 
  crystals 
  of 
  microcline 
  with 
  

   plagioclase, 
  scapolite, 
  augite, 
  hornblende, 
  epidote, 
  quartz 
  and 
  

   magnetite. 
  The 
  epidote 
  is 
  partly 
  an 
  alteration 
  product 
  of 
  the 
  

   plagioclase 
  feldspar 
  which 
  is 
  probably 
  oligoclase. 
  The 
  pegmatite 
  

   occurs 
  in 
  bodies 
  that 
  rarely 
  possess 
  any 
  regularity 
  of 
  outline 
  like 
  

   dikes, 
  though 
  this 
  may 
  be 
  due 
  to 
  the 
  squeezing 
  and 
  shearing 
  

   it 
  has 
  undergone. 
  Large 
  interlocking 
  masses 
  of 
  hornblende 
  and 
  

   augite 
  anhedra 
  occur 
  in 
  both 
  varieties 
  of 
  pegmatite. 
  During 
  

   the 
  course 
  of 
  mining 
  operations 
  vugs 
  and 
  cavities 
  are 
  frequently 
  

   opened 
  within 
  the 
  pegmatite 
  masses 
  and 
  some 
  have 
  afforded 
  

   remarkable 
  groups 
  of 
  well 
  crystallized 
  minerals. 
  

  

  Distribution 
  of 
  the 
  deposits 
  

  

  The 
  ore 
  bodies 
  which 
  have 
  been 
  mined 
  on 
  a 
  commercial 
  scale 
  

   lie 
  within 
  a 
  narrow 
  belt 
  extending 
  northeast 
  and 
  southwest 
  along 
  

   the 
  eastern 
  edge 
  of 
  the 
  valley. 
  They 
  have 
  been 
  proved 
  by 
  mag- 
  

   netic 
  attraction 
  and 
  borings 
  to 
  constitute 
  a 
  nearly 
  continuous 
  

   series 
  with 
  a 
  linear 
  extent 
  of 
  some 
  5 
  miles. 
  The 
  several 
  openings 
  

   in 
  the 
  belt 
  comprise 
  mine 
  81 
  on 
  the 
  southern 
  extremity, 
  the 
  main 
  

  

  