﻿ADIRONDACK 
  MAGNETIC 
  IRON 
  ORES 
  47 
  

  

  blende, 
  biotite, 
  apatite 
  and 
  magnetite. 
  It 
  has 
  a 
  more 
  or 
  less 
  

   gneissoid 
  appearance, 
  and 
  the 
  feldspar 
  which 
  originally 
  existed 
  

   in 
  porphyritic 
  crystals 
  has 
  been 
  considerably 
  crushed, 
  but 
  the 
  

   textural 
  relations 
  are 
  those 
  of 
  a 
  plutonic 
  igneous 
  rock. 
  It 
  is 
  regu- 
  

   larly 
  jointed 
  and 
  weathers 
  out 
  into 
  massive 
  blocks. 
  In 
  the 
  Knob 
  

   mountain 
  area 
  there 
  are 
  included 
  fragments 
  of 
  the 
  sedimentary 
  

   hornblende 
  gneiss 
  which 
  it 
  has 
  invaded. 
  The 
  Hammondville 
  

   gneiss 
  to 
  the 
  west 
  is 
  penetrated 
  by 
  dikes 
  and 
  irregular 
  masses 
  of 
  

   granitic 
  material 
  which 
  are 
  probably 
  offshoots 
  from 
  the 
  larger 
  

   intrusions. 
  

  

  Pegmatite 
  may 
  be 
  mentioned 
  as 
  of 
  frequent 
  occurrence 
  in 
  the 
  

   ore-bearing 
  gneiss. 
  In 
  almost 
  all 
  of 
  the 
  pits 
  this 
  rock 
  seems 
  to 
  

   have 
  been 
  encountered 
  during 
  the 
  mining 
  operations. 
  It 
  forms 
  

   masses 
  of 
  varying 
  size 
  and 
  shape 
  that 
  blend 
  with 
  the 
  country 
  

   rock, 
  and 
  is 
  quite 
  .often 
  associated 
  with 
  the 
  ore. 
  

  

  Distribution 
  and 
  stratigraphy 
  of 
  formations. 
  The 
  Hammond- 
  

   ville 
  gneiss 
  occupies 
  a 
  compact 
  area 
  about 
  2 
  J 
  miles 
  long 
  from 
  

   northeast, 
  near 
  Dudley 
  pond 
  and 
  its 
  outlet, 
  to 
  southwest 
  where 
  

   it 
  extends 
  to 
  within 
  a 
  short 
  distance 
  of 
  Burnt 
  Mill 
  brook. 
  Its 
  

   width 
  is 
  about 
  1 
  J 
  miles. 
  On 
  the 
  north 
  it 
  is 
  cut 
  off 
  by 
  the 
  intrusion 
  

   of 
  anorthosite 
  and 
  gabbro 
  that 
  stretches 
  over 
  many 
  square 
  miles 
  

   in 
  an 
  unbroken 
  mass. 
  On 
  the 
  other 
  sides 
  it 
  is 
  in 
  contact 
  with 
  the 
  

   sedimentary 
  series 
  which 
  occupies 
  the 
  valleys 
  of 
  Paradox 
  creek 
  

   on 
  the 
  west, 
  Burnt 
  Mill 
  brook 
  on 
  the 
  south 
  and 
  most 
  of 
  the 
  broad 
  

   ridge 
  between 
  Knob 
  mountain 
  and 
  Penfield 
  pond 
  in 
  a 
  connected 
  

   belt. 
  The 
  Skiff 
  mountain 
  gneiss 
  which 
  is 
  of 
  the 
  same 
  type 
  lies 
  

   across 
  the 
  valley 
  of 
  Burnt 
  Mill 
  brook 
  and 
  is 
  thus 
  completely 
  sepa- 
  

   rated 
  from 
  the 
  Hammondville 
  area. 
  The 
  contact 
  between 
  the 
  

   sedimentary 
  and 
  ore-bearing 
  gneisses 
  on 
  the 
  north 
  side 
  of 
  Skiff 
  

   mountain 
  appears 
  to 
  be 
  well 
  up 
  on 
  the 
  slopes. 
  

  

  The 
  main 
  granite 
  area 
  in 
  the 
  district 
  is 
  found 
  on 
  the 
  ridge 
  east 
  

   of 
  Hammondville. 
  It 
  takes 
  in 
  the 
  rounded 
  prominences 
  known 
  

   as 
  Knob 
  and 
  Little 
  Knob 
  mountains, 
  forming 
  an 
  irregular 
  mass 
  

   or 
  boss 
  intruded 
  in 
  the 
  sedimentary 
  series. 
  Whether 
  it 
  is 
  in 
  con- 
  

   tact 
  with 
  the 
  Hammondville 
  gneiss 
  to 
  the 
  west 
  could 
  not 
  be 
  defi- 
  

   nitely 
  determined, 
  but 
  from 
  field 
  observations 
  a 
  belt 
  of 
  sedimentary 
  

   gneisses 
  would 
  appear 
  to 
  intervene 
  for 
  most 
  if 
  not 
  the 
  entire 
  dis- 
  

   tance 
  on 
  that 
  side. 
  Both 
  Knob 
  and 
  Little 
  Knob 
  present 
  almost 
  

   vertical 
  cliffs 
  as 
  seen 
  from 
  the 
  west, 
  suggesting 
  a 
  north-south 
  

   fault 
  scarp, 
  a 
  feature 
  that 
  was 
  noted 
  by 
  Professor 
  Kemp. 
  There 
  

   is 
  no 
  direct 
  proof 
  of 
  the 
  existence 
  of 
  faulting 
  at 
  this 
  point, 
  though 
  

   in 
  a 
  rock 
  cut 
  of 
  the 
  abandoned 
  mine 
  railroad 
  2 
  miles 
  north 
  of 
  

  

  