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  NEW 
  YOEK 
  STATE 
  MUSEUM 
  

  

  On 
  the 
  borders 
  of 
  the 
  Adirondack 
  region 
  quarries 
  have 
  been 
  

   opened 
  in 
  the 
  towns 
  of 
  Wilton, 
  Hadley 
  and 
  Greenfield, 
  in 
  Sara- 
  

   toga 
  county; 
  at 
  Whitehall, 
  im 
  Washington 
  county; 
  at 
  Littlefalls, 
  

   in 
  Herkimer 
  county; 
  Cxrindstone 
  Island, 
  Jefferson 
  county; 
  and 
  

   near 
  Canton 
  in 
  St 
  Lawrence 
  county. 
  The 
  inaccessibility 
  of 
  much 
  

   of 
  this 
  region 
  and 
  the 
  distance 
  from 
  the 
  large 
  city 
  markets 
  have 
  

   prevented 
  the 
  opening 
  of 
  more 
  quarries 
  in 
  the 
  gneissic 
  rocks 
  on 
  

   the 
  borders 
  of 
  the 
  Adirondacks. 
  

  

  TRAP 
  

  

  Trap-rock 
  or 
  trap 
  is 
  the 
  common 
  name 
  given 
  to 
  a 
  class 
  of 
  

   eruptive 
  rocks 
  because 
  of 
  a 
  structural 
  peculiarity, 
  and 
  has 
  no 
  

   distinctive 
  significance 
  in 
  mineralogical 
  composition. 
  The 
  rocks 
  

   of 
  the 
  Palisade 
  mountain 
  range 
  and 
  of 
  the 
  Torn 
  mountain, 
  which 
  

   extends 
  from 
  the 
  New 
  Jersey 
  line, 
  on 
  the 
  west 
  shore 
  of 
  the 
  Hud- 
  

   eon 
  river 
  to 
  Haverstraw, 
  are 
  known 
  as 
  trap-rocks. 
  There 
  is 
  an 
  

   outcrop 
  on 
  Staten 
  Island, 
  at 
  Graniteville, 
  near 
  Port 
  Richmond, 
  

   where 
  a 
  large 
  amount 
  of 
  stone 
  has 
  been 
  quarried 
  at 
  the 
  so-called 
  

   * 
  granite 
  quarries.' 
  

  

  The 
  trap-rock 
  of 
  the 
  Palisades 
  range 
  is 
  a 
  crystalline, 
  granular 
  

   mass 
  of 
  plagioclase 
  feldspar 
  (usually 
  labradorite) 
  augite 
  and 
  

   magnetite. 
  It 
  is 
  generally 
  finer 
  crystalline 
  than 
  the 
  granite. 
  

   The 
  colors 
  vary 
  from 
  dark 
  gray 
  through 
  dark 
  green 
  to 
  almost 
  

   black. 
  

  

  This 
  trap-rock 
  is 
  hard 
  and 
  tough, 
  but 
  some 
  of 
  it 
  is 
  split 
  readily 
  

   into 
  blocks 
  for 
  paving. 
  It 
  has 
  been 
  used 
  extensively 
  in 
  New 
  

   York 
  and 
  adjacent 
  cities 
  for 
  street 
  paving, 
  but 
  since 
  the 
  introduc- 
  

   tion 
  of 
  granite 
  blocks 
  this 
  use 
  has 
  nearly 
  ceased. 
  On 
  account 
  

   of 
  its 
  toughness 
  it 
  makes 
  an 
  admirable 
  material 
  for 
  macadamiz- 
  

   ing 
  roadways. 
  It 
  is 
  so 
  hard 
  that 
  only 
  rock-face 
  blocks 
  are 
  used 
  

   in 
  constructive 
  work. 
  Several 
  prominent 
  buildings 
  in 
  Jersey 
  

   City 
  and 
  Hoboken 
  are 
  built 
  of 
  it. 
  There 
  is 
  a 
  large 
  quarry 
  on 
  the 
  

   river 
  at 
  Rockland 
  lake, 
  near 
  Haverstraw, 
  the 
  output 
  of 
  which 
  

   is 
  for 
  street 
  work 
  and 
  road 
  material 
  almost 
  exclusively. 
  There 
  

   are 
  also 
  quarries 
  at 
  Piermont 
  and 
  at 
  Graniteville, 
  Staten 
  Island. 
  

  

  