﻿I48 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  weather. 
  For 
  the 
  glacier 
  to 
  leave 
  a 
  block 
  of 
  such 
  shape 
  in 
  such 
  

   position 
  in 
  such 
  a 
  commanding 
  situation 
  is 
  highly 
  exceptional, 
  and 
  

   it 
  is 
  one 
  of 
  the 
  most 
  striking 
  objects 
  of 
  the 
  kind 
  that 
  we 
  have 
  had 
  

   the 
  privilege 
  of 
  becoming 
  acquainted 
  with. 
  

  

  ECONOMIC 
  GEOLOGY 
  

  

  BY 
  H. 
  P. 
  CUSHING 
  

  

  Molding 
  sand. 
  There 
  is 
  a 
  large 
  annual 
  output 
  of 
  molding 
  sand 
  

   from 
  the 
  general 
  Hudson 
  river 
  region 
  in 
  New 
  York, 
  especially 
  

   from 
  the 
  vicinity 
  of 
  Albany. 
  The 
  Schuylerville 
  quadrangle 
  makes 
  

   a 
  considerable 
  contribution 
  to 
  this 
  output, 
  the 
  material 
  coming 
  

   from 
  near 
  the 
  surface, 
  just 
  underneath 
  the 
  soil. 
  The 
  sand 
  forms 
  

   part 
  of 
  the 
  deposits 
  of 
  Lake 
  Albany, 
  which 
  cover 
  most 
  of 
  the 
  sur- 
  

   face 
  below 
  the 
  300 
  foot 
  level 
  on 
  the 
  Schuylerville 
  quadrangle. 
  For 
  

   foundry 
  purposes 
  a 
  sand 
  must 
  have 
  a 
  certain 
  degree 
  of 
  refractori- 
  

   ness, 
  cohesiveness, 
  and 
  porosity. 
  Durability 
  is 
  also 
  important, 
  as 
  

   is 
  texture, 
  but 
  sands 
  of 
  considerable 
  difference 
  in 
  size 
  of 
  grain 
  may 
  

   be 
  used, 
  the 
  coarser 
  for 
  one 
  kind 
  of 
  castings 
  and 
  the 
  finer 
  for 
  

   another. 
  The 
  cohesiveness 
  results 
  from 
  the 
  sand 
  occurring 
  mixed 
  

   with 
  a 
  certain 
  percentage 
  of 
  clayey 
  matter. 
  

  

  The 
  deposits 
  of 
  molding 
  sand 
  have 
  no 
  great 
  thickness, 
  running 
  

   from 
  8 
  or 
  9 
  inches 
  up 
  to 
  a 
  few 
  feet 
  thick. 
  They 
  commonly 
  pass 
  

   into 
  worthless 
  sand 
  below. 
  Good 
  natural 
  molding 
  sands 
  are 
  not 
  

   very 
  common, 
  so 
  that 
  the 
  demand 
  rather 
  exceeds 
  the 
  supply. 
  

  

  Graphite. 
  Mining 
  for 
  graphite 
  has 
  been 
  carried 
  on 
  at 
  two 
  dif- 
  

   ferent 
  localities 
  on 
  the 
  Saratoga 
  quadrangle, 
  both 
  of 
  them 
  quite 
  

   recent 
  projects. 
  The 
  older 
  and 
  larger 
  of 
  the 
  two 
  establishments 
  

   is 
  situated 
  about 
  2 
  miles 
  west 
  of 
  Porter 
  Corners 
  on 
  the 
  fault 
  plane 
  

   scarp 
  of 
  the 
  Hoffmans 
  fault. 
  The 
  other 
  is 
  4 
  miles 
  north 
  of 
  Sara- 
  

   toga 
  Springs, 
  and 
  similarly 
  situated 
  on 
  the 
  McGregor 
  fault 
  plane 
  

   scarp. 
  The 
  rock 
  is 
  quite 
  similar 
  at 
  the 
  two 
  localities 
  and 
  seems 
  

   to 
  represent 
  the 
  same 
  horizon 
  in 
  the 
  Grenville 
  series, 
  a 
  horizon 
  in 
  

   the 
  quartzite 
  formation. 
  At 
  the 
  time 
  of 
  our 
  study 
  only 
  the 
  estab- 
  

   lishment 
  at 
  Porter 
  Corners, 
  the 
  Empire 
  Graphite 
  Company, 
  was 
  

   in 
  operation. 
  

  

  The 
  Grenville 
  beds 
  at 
  this 
  locality 
  have 
  a 
  N. 
  70 
  E. 
  strike 
  and 
  a 
  

   dip 
  of 
  from 
  30 
  to 
  50 
  to 
  the 
  south. 
  The 
  surface 
  beds 
  are 
  soft 
  

   and 
  badly 
  altered 
  graphite 
  and 
  mica 
  schists. 
  They 
  are 
  quartz- 
  

   feldspar-graphite 
  and 
  quartz-feldspar-phlogopite 
  rocks, 
  averaging 
  

   50 
  per 
  cent 
  quartz, 
  30 
  to 
  40 
  per 
  cent 
  of 
  feldspar 
  and 
  the 
  remainder 
  

  

  