﻿ECONOMIC 
  GEOLOGY 
  183 
  

  

  posable 
  varieties 
  of 
  pyrite 
  is 
  not 
  only 
  prejudicial 
  to 
  strength 
  

   and 
  durability 
  but 
  also 
  to 
  the 
  beauty 
  of 
  the 
  stone 
  as 
  soon 
  as 
  it 
  

   begins 
  to 
  decay. 
  

  

  The 
  term 
  ' 
  granite 
  ' 
  as 
  used 
  among 
  builders 
  and 
  architects 
  is 
  

   not 
  restricted 
  to 
  rock 
  species 
  of 
  this 
  name 
  in 
  geologic 
  nomencla- 
  

   ture, 
  but 
  includes 
  what 
  are 
  known 
  as 
  gneisses 
  (foliated 
  and 
  

   bedded 
  granites), 
  diorites, 
  gabbro 
  and 
  other 
  crystalline 
  rocks 
  

   whose 
  uses 
  are 
  the 
  same. 
  In 
  fact, 
  the 
  similar 
  adaptability 
  and 
  

   use 
  have 
  brought 
  the 
  latter 
  species 
  into 
  the 
  class 
  of 
  granites. 
  

   For 
  example, 
  the 
  Au 
  Sable 
  granite 
  of 
  Essex 
  county 
  is 
  a 
  norite. 
  

   The 
  term 
  is 
  applied 
  in 
  some 
  cases 
  to 
  the 
  diabases 
  or 
  trap-rocks, 
  

   as 
  the- 
  ^ 
  granite 
  quarries 
  ' 
  of 
  Staten 
  Island. 
  

  

  Another 
  massive 
  crystalline 
  rock 
  which 
  is 
  used 
  in 
  building 
  is 
  

   norite, 
  consisting 
  of 
  labradorite 
  and 
  hypersthene, 
  with 
  some 
  

   brown 
  mica. 
  It 
  is 
  a 
  common 
  rock 
  in 
  the 
  Adirondack 
  region, 
  and 
  

   is 
  known 
  commercially 
  as 
  a 
  granite. 
  

  

  The 
  massive 
  crystalline 
  rocks 
  are 
  of 
  common 
  occurrence 
  in 
  

   New 
  York, 
  but 
  not 
  in 
  outcrops 
  over 
  extensive 
  areas, 
  excepting 
  

   in 
  the 
  Adirondack 
  region 
  and 
  in 
  the 
  Highlands 
  of 
  the 
  Hudson. 
  

   The 
  schistose 
  crystalline 
  rocks 
  are 
  developed 
  extensively 
  in 
  the 
  

   Highlands 
  of 
  the 
  Hudson 
  and 
  on 
  the 
  borders 
  of 
  the 
  Adirondack 
  

   region. 
  On 
  New 
  York 
  island 
  and 
  within 
  the 
  city 
  limits 
  the 
  

   gneiss 
  rocks 
  have 
  been 
  quarried 
  at 
  many 
  points. 
  In 
  Westchester 
  

   county 
  there 
  are 
  belts 
  of 
  gneiss 
  and 
  mica 
  schist, 
  in 
  which 
  quarries 
  

   have 
  been 
  opened 
  near 
  Hastings; 
  near 
  Hartsdale, 
  east 
  of 
  Yonk- 
  

   ers; 
  at 
  Kensico; 
  at 
  Tarrytown 
  and 
  at 
  Ganung's, 
  west 
  of 
  Croton 
  

   Falls. 
  In 
  Putnam 
  county 
  there 
  are 
  quarries 
  of 
  granite 
  near 
  

   Peekskill, 
  Garrison's 
  and 
  Cold 
  Spring. 
  West 
  of 
  the 
  Hudson 
  

   river 
  there 
  are 
  quarries 
  on 
  lona 
  island; 
  at 
  West 
  Point; 
  on 
  Storm 
  

   King 
  mountain, 
  near 
  Cornwall; 
  near 
  Suffern; 
  at 
  Ramapo; 
  and 
  

   on 
  Mount 
  Eve, 
  near 
  Florida. 
  The 
  outcrops 
  of 
  the 
  gneissoid 
  and 
  

   granitoid 
  rocks 
  are 
  so 
  numerous 
  in 
  the 
  belt 
  of 
  the 
  Hudson 
  High- 
  

   lands 
  that 
  quarries 
  can 
  be 
  opened 
  at 
  many 
  points. 
  The 
  supply 
  

   of 
  stone 
  is 
  inexhaustible. 
  On 
  the 
  Hudson 
  river, 
  between 
  Peeks- 
  

   kill 
  and 
  Fishkill, 
  there 
  is 
  a 
  ^ne 
  section 
  of 
  these 
  rocks 
  exposed. 
  

  

  