﻿22 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  quartz 
  crystals 
  are 
  also 
  decidedly 
  flattened 
  parallel 
  to 
  the 
  folia- 
  

   tion. 
  The 
  phenocrysts 
  are 
  embedded 
  in 
  a 
  fine 
  to 
  medium-grained 
  

   matrix 
  of 
  feldspar, 
  quartz, 
  and 
  biotite 
  or 
  hornblende. 
  The 
  rock 
  

   nearly 
  always 
  shows 
  the 
  effects 
  of 
  dynamic 
  metamorphism, 
  the 
  

   more 
  or 
  less, 
  crushed 
  and 
  granulated 
  feldspars 
  generally 
  being 
  

   clearly 
  visible 
  to 
  the 
  naked 
  eye. 
  The 
  degree 
  of 
  foliation 
  often 
  

   varies 
  considerably 
  from 
  place 
  to 
  place, 
  and 
  the 
  porphyritic 
  tex- 
  

   ture, 
  especially 
  along 
  the 
  borders, 
  becomes 
  notably 
  less 
  prominent. 
  

   The 
  general 
  range 
  in 
  mineral 
  composition 
  is 
  shown 
  by 
  the 
  

   examples 
  given 
  in 
  table 
  3. 
  

  

  table 
  3 
  

   Granite 
  porphyry 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  0> 
  

  

  t3 
  

  

  <u 
  

  

  Xi 
  

  

  <D 
  

  

  <u 
  

  

  

  

  

  

  

  

  

  

  

  

   6 
  

  

  J5 
  

   

  

  O 
  

  

  <D 
  

  

  a 
  

   

   

  

  73 
  

   

  

  U 
  

  

  

   '1 
  

  

  a 
  

  

  u 
  

  

  

  

  c 
  

  

  ffl 
  

  

  a 
  

  

  i 
  

  

  a 
  

   

   

   i-i 
  

  

  '0 
  

   t-3 
  

  

  a 
  

  

  < 
  

  

  C 
  

   u 
  

  

  a 
  

   O 
  

  

  

  

  

  

  

  Ol-And 
  

  

  

  

  

  

  

  

  

  

  1 
  

  

  25 
  

  

  10 
  

  

  10 
  

  

  25 
  

  

  Ol-And 
  

  

  44 
  

  

  4 
  

  

  4 
  

  

  

  1 
  

  

  4 
  

  

  h 
  

  

  £ 
  

  

  I 
  

  

  2 
  

  

  26 
  

  

  10 
  

  

  10 
  

  

  25 
  

  

  5 
  

  

  30 
  

  

  10 
  

  

  

  1 
  

  

  \ 
  

  

  1 
  

   2 
  

  

  1 
  

  

  4 
  

  

  8 
  

  

  3 
  

  

  27 
  

  

  15 
  

  

  20 
  

  

  20 
  

  

  01- 
  And' 
  

  

  30 
  

  

  8 
  

  

  

  1 
  

  

  1 
  

   4 
  

  

  2 
  

  

  4 
  

  

  5 
  

  

  A 
  

  

  28 
  

  

  8 
  

  

  35 
  

  

  8 
  

  

  7 
  

  

  30 
  

  

  

  10 
  

  

  1 
  

  

  1 
  

  

  1 
  

  

  1 
  

   4 
  

  

  

  Number 
  1 
  is 
  a 
  very 
  typical 
  looking 
  granite 
  porphyry 
  from 
  the 
  

   quarry 
  at 
  Horicon. 
  This 
  is 
  the 
  rock 
  which 
  Professor 
  Kemp 
  de- 
  

   scribed 
  as 
  the 
  " 
  Horicon 
  gneiss 
  " 
  some 
  years 
  ago. 
  1 
  

  

  Number 
  2 
  is 
  from 
  Kelm 
  mountain; 
  no. 
  3 
  from 
  one 
  mile 
  south 
  of 
  

   Kelm 
  mountain; 
  and 
  no. 
  4 
  from 
  the 
  south 
  base 
  of 
  Prospect 
  

   mountain. 
  

  

  A 
  good 
  example 
  of 
  a 
  rather 
  coarse, 
  somewhat 
  porphyritic, 
  pink 
  

   granite 
  which 
  might 
  almost 
  pass 
  for 
  a 
  granite 
  porphyry 
  occurs 
  in 
  

   the 
  quarry 
  along 
  the 
  road 
  2 
  miles 
  northeast 
  of 
  Pottersville. 
  

  

  It 
  so 
  happened 
  that 
  no 
  Grenville 
  masses 
  within 
  the 
  granite 
  por- 
  

   phyry 
  were 
  of 
  sufficient 
  size 
  to 
  be 
  indicated 
  on 
  the 
  geologic 
  map, 
  

   but 
  in 
  the 
  field 
  one 
  may 
  see 
  a 
  good 
  many 
  small 
  patches 
  or 
  streaks 
  

   of 
  Grenville 
  gneiss 
  sometimes 
  as 
  clear-cut 
  inclusions 
  and 
  at 
  other 
  

   times 
  seemingly 
  more 
  or 
  less 
  fused 
  into 
  the 
  granite, 
  thus 
  giving 
  

   very 
  locally 
  a 
  sort 
  of 
  mixed 
  gneiss 
  effect. 
  

  

  1 
  17th 
  Annual 
  Rep't 
  N. 
  Y. 
  State 
  Geol. 
  1897, 
  P- 
  5 
  10, 
  54i- 
  

  

  