﻿GEOLOGY 
  OF 
  SARATOGA 
  SPRINGS 
  AND 
  VICINITY 
  149 
  

  

  a 
  varying 
  mixture 
  of 
  graphite 
  and 
  phlogopite 
  with 
  some 
  apatite. 
  

   The 
  feldspars 
  are 
  so 
  badly 
  altered 
  as 
  to 
  defy 
  exact 
  determination, 
  

   but 
  in 
  part 
  at 
  least 
  consist 
  of 
  plagioclase, 
  likely 
  oligoclase. 
  Two 
  

   beds 
  are 
  being 
  utilized, 
  or 
  are 
  capable 
  of 
  utilization, 
  because 
  of 
  

   high 
  graphite 
  and 
  low 
  mica 
  content. 
  The 
  upper 
  bed, 
  from 
  10 
  to 
  

   14 
  feet 
  thick, 
  has 
  been 
  the 
  one 
  chiefly 
  worked 
  up 
  to 
  date. 
  The 
  

   lower 
  bed 
  is 
  much 
  thinner. 
  They 
  are 
  separated 
  by 
  a 
  four- 
  

   foot 
  thickness 
  of 
  quartzite 
  and 
  thin 
  limestone. 
  Underneath 
  is 
  a 
  

   much 
  more 
  solid 
  bed 
  of 
  mica 
  gneiss. 
  The 
  whole 
  overlies 
  massive 
  

   quartzite 
  and, 
  like 
  all 
  the 
  Grenville 
  of 
  the 
  quadrangle, 
  is 
  more 
  or 
  

   less 
  involved 
  with 
  the 
  white, 
  garnet-bearing 
  granite 
  which 
  we 
  re- 
  

   gard 
  as 
  Laurentian. 
  There 
  has 
  been 
  an 
  irregular 
  output 
  of 
  graphite 
  

   by 
  this 
  company 
  since 
  1906, 
  the 
  production 
  being 
  exclusively 
  flake 
  

   graphite. 
  

  

  Much 
  the 
  same 
  assemblage 
  of 
  rocks 
  is 
  shown 
  at 
  the 
  pit 
  of 
  the 
  

   Saratoga 
  Graphite 
  Company, 
  but 
  this 
  is 
  a 
  newer 
  enterprise 
  with 
  

   much 
  less 
  accomplished 
  in 
  the 
  way 
  of 
  exploitation. 
  Similar 
  weak, 
  

   altered 
  schists 
  are 
  shown, 
  of 
  the 
  same 
  mmeralogic 
  make-up 
  as 
  at 
  

   Porter 
  Corners. 
  We 
  saw 
  no 
  rock 
  so 
  free 
  from 
  mica 
  as 
  are 
  the 
  

   two 
  beds 
  worked 
  by 
  the 
  Empire 
  company, 
  though 
  further 
  explo- 
  

   ration 
  may 
  disclose 
  equally 
  good 
  material. 
  The 
  strike 
  here 
  is 
  

   N 
  8o° 
  E, 
  and 
  30 
  south 
  dip, 
  and 
  the 
  general 
  similarity 
  of 
  the 
  rock 
  

   association 
  strongly 
  suggests 
  that 
  we 
  are 
  dealing 
  with 
  the 
  same 
  

   rock 
  horizon. 
  

  

  Stone 
  quarries. 
  Quarries 
  have 
  been 
  opened 
  in 
  several 
  of 
  the 
  

   formations 
  of 
  the 
  two 
  quadrangles, 
  in 
  the 
  Precambric 
  granite 
  and 
  

   trap, 
  in 
  the 
  Little 
  Falls 
  dolomite, 
  the 
  Amsterdam 
  limestone, 
  the 
  

   Bald 
  Mountain 
  limestone, 
  and 
  the 
  Northumberland 
  volcanic 
  plug. 
  

  

  Laurentian 
  granite. 
  A 
  small 
  quarry 
  has 
  been 
  opened 
  in 
  the 
  

   Laurentian 
  white 
  granite 
  on 
  the 
  face 
  of 
  the 
  McGregor 
  fault 
  plane 
  

   scarp, 
  2 
  miles 
  north 
  of 
  Saratoga. 
  Like 
  all 
  the 
  granite 
  of 
  the 
  dis- 
  

   trict 
  it 
  contains 
  Grenville 
  material 
  in 
  all 
  stages 
  of 
  absorption. 
  But 
  

   the 
  quantity 
  of 
  such 
  inclusions 
  of 
  schist 
  is 
  much 
  less 
  here 
  than 
  

   elsewhere, 
  the 
  granite 
  is 
  massive 
  and 
  solid 
  and 
  of 
  pleasing 
  color, 
  

   and 
  there 
  seems 
  no 
  reason 
  why 
  it 
  should 
  not 
  make 
  a 
  most 
  excel- 
  

   lent 
  structural 
  material 
  for 
  many 
  purposes. 
  The 
  location, 
  how- 
  

   ever, 
  is 
  unfortunate, 
  the 
  quarry 
  being 
  situated 
  well 
  up 
  the 
  steep 
  

   slope 
  of 
  the 
  fault 
  plane 
  scarp, 
  rendering 
  cartage 
  difficult 
  and 
  

   expensive. 
  

  

  Trap. 
  A 
  large 
  quarry 
  has 
  been 
  opened 
  on 
  one 
  of 
  the 
  large 
  

   diabase 
  dikes 
  where 
  it 
  is 
  crossed 
  by 
  the 
  North 
  Creek 
  branch 
  of 
  

  

  