﻿IRON 
  ORES 
  OF 
  THE 
  CLINTON 
  FORMATION 
  47 
  

  

  they 
  are 
  observable 
  only 
  with 
  the 
  aid 
  of 
  the 
  microscope. 
  The 
  kernels 
  

   sometimes 
  appear 
  to 
  be 
  wholly 
  absent. 
  The 
  quartz 
  has 
  the 
  same 
  

   character 
  as 
  that 
  found 
  in 
  granitic 
  rocks, 
  showing 
  liquid 
  and 
  gas 
  

   inclusions, 
  as 
  well 
  as 
  rutile 
  and 
  hematite 
  crystals. 
  Its 
  ultimate 
  

   source, 
  undoubtedly, 
  is 
  the 
  Precambric 
  crystallines, 
  but 
  the 
  small 
  

   size 
  of 
  the 
  grains 
  and 
  their 
  well 
  rounded 
  forms 
  indicate 
  long 
  con- 
  

   tinued 
  abrasion 
  after 
  its 
  release 
  from 
  the 
  rocks. 
  

  

  The 
  texture 
  of 
  the 
  fossiliferous 
  ore 
  varies 
  to 
  some 
  extent 
  with 
  

   the 
  locality. 
  In 
  the 
  red 
  flux 
  bed 
  as 
  exposed 
  at 
  Clinton, 
  the 
  fossil 
  

   fragments 
  are 
  coarse 
  and 
  the 
  different 
  forms 
  can 
  be 
  separated 
  and 
  

   identified 
  without 
  difficulty. 
  In 
  the 
  western 
  part 
  of 
  the 
  State, 
  the 
  

   beds 
  show 
  much 
  finer 
  texture, 
  while 
  the 
  shell 
  particles 
  have 
  been 
  

   worn 
  and 
  smoothed 
  until 
  their 
  organic 
  nature 
  is 
  more 
  or 
  less 
  con- 
  

   cealed. 
  The 
  smaller 
  fragments 
  are 
  often 
  enveloped 
  by 
  one 
  or 
  more 
  

   layers 
  of 
  hematite 
  deposited 
  after 
  their 
  replacement 
  in 
  the 
  same 
  

   way 
  as 
  with 
  the 
  oolitic 
  grains. 
  

  

  The 
  cementing 
  material 
  in 
  both 
  kinds 
  of 
  ore 
  is 
  usually 
  granular 
  

   calcite. 
  There 
  is 
  considerable 
  variation 
  in 
  the 
  relative 
  proportion 
  

   of 
  this 
  mineral 
  to 
  the 
  hematite. 
  Local 
  variations 
  may 
  be 
  ascribed 
  

   to 
  solution 
  of 
  the 
  calcite 
  after 
  the 
  ores 
  w 
  T 
  ere 
  laid 
  down, 
  but 
  it 
  is 
  

   also 
  to 
  be 
  expected 
  that 
  the 
  conditions 
  of 
  deposition 
  would 
  change 
  

   from 
  time 
  to 
  time 
  and 
  from 
  place 
  to 
  place. 
  An 
  exceptional 
  type 
  is 
  

   represented 
  in 
  the 
  eastern 
  section 
  in 
  Herkimer 
  county 
  where 
  there 
  

   are 
  one 
  or 
  more 
  layers 
  of 
  what 
  is 
  properly 
  a 
  ferruginous 
  sandstone. 
  

   The 
  fine 
  quartz 
  grains 
  are 
  not 
  coated 
  with 
  hematite 
  to 
  any 
  extent, 
  

   but 
  the 
  latter 
  fills 
  the 
  interstices 
  as 
  cement. 
  The 
  material 
  is 
  too 
  

   lean 
  to 
  be 
  classed 
  as 
  an 
  ore. 
  

  

  Chemical 
  character 
  

  

  The 
  Clinton 
  ores 
  show 
  considerable 
  regularity 
  in 
  their 
  chemical 
  

   composition. 
  Leaving 
  out 
  of 
  consideration 
  the 
  locally 
  occurring 
  

   beds 
  which 
  are 
  generally 
  too 
  lean 
  or 
  too 
  thin 
  to 
  be 
  workable, 
  the 
  ores 
  

   throughout 
  the 
  State 
  may 
  be 
  said 
  to 
  average 
  about 
  40$ 
  in 
  metallic 
  

   iron. 
  They 
  seldom 
  run 
  above 
  45^ 
  or 
  less 
  than 
  35^. 
  The 
  higher 
  

   limit 
  is 
  approximated 
  by 
  the 
  oolitic 
  bed 
  in 
  the 
  vicinity 
  of 
  Clinton, 
  

   where 
  the 
  mines 
  of 
  the 
  Franklin 
  Furnace 
  Co. 
  have 
  returned 
  an 
  

   average 
  of 
  44$ 
  through 
  a 
  period 
  of 
  several 
  years. 
  The 
  care 
  taken 
  

   in 
  separating 
  the 
  ore 
  from 
  the 
  inclosing 
  rock 
  and 
  in 
  the 
  removal 
  of 
  

   shale, 
  sandstone 
  or 
  limestone 
  partings 
  which 
  are 
  often 
  present, 
  is 
  an 
  

   important 
  factor 
  in 
  determining 
  the 
  yield. 
  According 
  to 
  C. 
  A. 
  Borst, 
  

   the 
  middle 
  portion 
  of 
  the 
  Clinton 
  oolitic 
  bed 
  can 
  be 
  mined 
  to 
  give 
  

  

  