﻿370 
  T. 
  N. 
  Dale 
  — 
  Local 
  Unconformity 
  between 
  

  

  thin 
  section 
  show 
  grains 
  of 
  microcline 
  with 
  streaks 
  of 
  

   inclusions 
  of 
  graphite 
  and 
  muscovite 
  arranged 
  parallel 
  to 
  

   the 
  laminae. 
  

  

  The 
  nearest 
  large 
  ontcrops 
  on 
  the 
  western 
  side 
  of 
  the 
  

   outlier 
  are 
  300-400 
  ft. 
  from 
  it 
  and 
  consist 
  of 
  white 
  calcite 
  

   marble 
  rarely 
  with 
  a 
  bed 
  of 
  dolomite. 
  "Within 
  500 
  ft. 
  N. 
  

   of 
  the 
  northern 
  end 
  there 
  are 
  gray 
  and 
  white 
  calcite 
  

   marbles 
  with 
  a 
  N. 
  strike. 
  Calcite 
  marble, 
  nearly 
  vertical, 
  

   is 
  in 
  contact 
  with 
  the 
  schist 
  at 
  its 
  extreme 
  northern 
  end 
  

   and 
  recurs 
  off 
  and 
  on 
  for 
  500 
  ft. 
  W. 
  

  

  The 
  pebbles 
  are 
  of 
  three 
  kinds 
  of 
  rock: 
  (1) 
  Calcite 
  

   marble, 
  dark 
  gray, 
  graphitic. 
  The 
  calcite 
  grains 
  have 
  a 
  

   maximum 
  diameter 
  of 
  148 
  millim., 
  estimated 
  average 
  0-37 
  

   millim. 
  It 
  contains 
  some 
  quartz 
  and 
  muscovite 
  and 
  a 
  

   few 
  grains 
  of 
  apatite. 
  (2) 
  Calcite 
  marble, 
  dark 
  gray, 
  

   graphitic, 
  also 
  brownish. 
  The 
  calcite 
  grains 
  have 
  a 
  

   maximum 
  diameter 
  of 
  1-12 
  millim., 
  estimated 
  average 
  

   0-25 
  millim. 
  It 
  contains 
  dolomitic 
  rhombs 
  within 
  and 
  

   between 
  the 
  calcite 
  grains, 
  also 
  evenly 
  disseminated 
  

   quartz, 
  some 
  pyrite 
  with 
  limonite 
  stain, 
  and 
  rarely 
  a 
  

   grain 
  of 
  albite. 
  (3) 
  One 
  small 
  pebble 
  is 
  a 
  black 
  very 
  

   graphitic 
  granular 
  dolomite 
  with 
  a 
  little 
  quartz 
  and 
  

   pyrite. 
  The 
  dolomite 
  rhombs 
  and 
  rhomboids, 
  averaging 
  

   about 
  0-033 
  millim. 
  in 
  diameter, 
  lie 
  in 
  a 
  groundmass 
  of 
  

   graphite 
  with 
  a 
  few 
  minute 
  grains 
  of 
  quartz 
  and 
  a 
  little 
  

   pyrite. 
  

  

  The 
  exact 
  source 
  of 
  the 
  graphitic 
  calcite 
  marble 
  of 
  (1) 
  

   and 
  (2) 
  is 
  as 
  yet 
  undetermined 
  but 
  may 
  very 
  well 
  have 
  

   been 
  some 
  of 
  the 
  uppermost 
  beds 
  of 
  the 
  Stockbridge 
  lime- 
  

   stone 
  which 
  are 
  apt 
  to 
  be 
  more 
  or 
  less 
  graphitic. 
  The 
  

   marble 
  outcrops 
  about 
  the 
  outlier 
  afford 
  but 
  a 
  very 
  incom- 
  

   plete 
  exhibit 
  of 
  the 
  uppermost 
  beds. 
  Furthermore 
  the 
  

   pebbles 
  may 
  have 
  been 
  transported 
  some 
  distance 
  to 
  their 
  

   present 
  location 
  in 
  the 
  sea 
  bottom. 
  

  

  This 
  locality 
  appears 
  to 
  be 
  the 
  only 
  one 
  known 
  in 
  the 
  

   Taconic 
  region 
  affording 
  evidence 
  of 
  any 
  unconformity 
  

   between 
  these 
  two 
  formations. 
  The 
  recent 
  mapping 
  of 
  

   the 
  dolomitic 
  and 
  calcitic 
  areas 
  of 
  the 
  Stockbridge 
  lime- 
  

   stone 
  in 
  Berkshire 
  County 
  shows 
  that 
  in 
  places, 
  notably 
  

   in 
  the 
  townships 
  of 
  Cheshire, 
  Lanesboro 
  and 
  Stockbridge, 
  

   the 
  Berkshire 
  schist 
  rests 
  immediately 
  upon 
  the 
  dolomitic 
  

   limestone 
  which 
  forms 
  the 
  lower 
  horizon 
  of 
  the 
  formation 
  

   but 
  in 
  most 
  places 
  upon 
  the 
  calcitic 
  limestone 
  or 
  upper 
  

   horizon. 
  This 
  may 
  be 
  attributed 
  either 
  to 
  the 
  contin- 
  

  

  