﻿52 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  the 
  scarcity 
  of 
  inclusions 
  of 
  other 
  types, 
  and 
  the 
  invariable 
  utter 
  

   absence 
  of 
  limestone 
  inclusions, 
  notwithstanding 
  the 
  abundance 
  

   of 
  limestone 
  in 
  the 
  formation. 
  Beyond 
  doubt 
  many 
  of 
  these 
  in- 
  

   clusions 
  represent 
  limestone 
  fragments 
  altered 
  in 
  this 
  fashion. 
  In- 
  

   tense 
  alteration, 
  however, 
  seems 
  necessary, 
  and 
  that 
  perhaps 
  fur- 
  

   nishes 
  a 
  reason 
  why 
  the 
  comparatively 
  small 
  fragments 
  caught 
  up 
  

   in 
  the 
  granite 
  mass 
  are 
  so 
  uniformly 
  changed 
  over, 
  while 
  at 
  the 
  

   contacts 
  the 
  change 
  is 
  much 
  less 
  obvious, 
  or 
  common. 
  In 
  our 
  dis- 
  

   trict 
  here 
  we 
  have 
  amphibolite 
  inclusions 
  everywhere 
  in 
  the 
  granite 
  

   gneisses, 
  but 
  no 
  instances 
  of 
  the 
  conversion 
  of 
  pure 
  limestone 
  into 
  

   amphibolite 
  along 
  the 
  contacts, 
  similar 
  to 
  those 
  in 
  Ontario. 
  There 
  

   are, 
  however, 
  one 
  or 
  two 
  instances 
  of 
  similar 
  alteration 
  on 
  a 
  small 
  

   scale, 
  in 
  connection 
  with 
  narrow 
  bands 
  of 
  limestone 
  and 
  small 
  

   granite 
  intrusions. 
  The 
  most 
  clearly 
  shown 
  of 
  these 
  is 
  right 
  in 
  

   the 
  village 
  of 
  Theresa, 
  at 
  the 
  road 
  metal 
  quarry 
  near 
  the 
  lower 
  

   bridge. 
  The 
  rock 
  quarried 
  here 
  is 
  a 
  contact 
  phase 
  of 
  the 
  limestone 
  

   cut 
  through 
  and 
  through 
  by 
  granite 
  dikes. 
  The 
  chief 
  rock 
  is 
  green 
  

   in 
  color 
  and 
  consists 
  of 
  pyroxene, 
  titanite, 
  feldspars 
  and 
  calcite, 
  the 
  

   latter 
  running 
  as 
  high 
  as 
  50^ 
  of 
  the 
  whole 
  in 
  the 
  portions 
  of 
  the 
  

   rock 
  most 
  remote 
  from 
  the 
  dikes. 
  In 
  contact 
  with 
  these, 
  however, 
  

   the 
  rock 
  is 
  black, 
  consists 
  chiefly 
  of 
  hornblende 
  and 
  feldspars, 
  

   though 
  with 
  a 
  little 
  remaining 
  pyroxene 
  and 
  calcite, 
  and 
  has 
  nearly 
  

   completed 
  its 
  transformation 
  into 
  amphibolite. 
  Very 
  near 
  at 
  hand 
  

   is 
  the 
  pure 
  limestone 
  band 
  shown 
  in 
  plate 
  2, 
  and 
  there 
  can 
  be 
  little 
  

   question 
  but 
  that 
  the 
  green 
  rock 
  of 
  the 
  quarry 
  is 
  an 
  altered 
  phase 
  

   of 
  that, 
  and 
  no 
  question 
  at 
  all 
  but 
  that 
  the 
  green 
  rock 
  is 
  changed 
  

   into 
  amphibolite 
  by 
  the 
  granite. 
  On 
  a 
  small 
  scale 
  then 
  it 
  is 
  a 
  

   change 
  identical 
  with 
  that 
  described 
  by 
  Adams. 
  

  

  Contact 
  rocks 
  of 
  the 
  Antzuerp 
  hathylith. 
  In 
  so 
  far 
  at 
  least 
  as 
  

   the 
  portion 
  of 
  the 
  Antwerp 
  bathylith 
  included 
  within 
  the 
  mapped 
  

   district 
  is 
  concerned, 
  the 
  contact 
  action 
  of 
  this 
  granite 
  is 
  but 
  slight, 
  

   and 
  it 
  would 
  seem 
  to 
  have 
  been 
  quite 
  deficient 
  in 
  mineralizing 
  

   agents, 
  though 
  as 
  effective 
  in 
  the 
  production 
  of 
  mixed 
  rocks 
  as 
  the 
  

   other 
  granites. 
  The 
  dikes 
  and 
  stocks 
  of 
  white 
  granite 
  run 
  every- 
  

   where 
  through 
  the 
  limestones 
  without 
  affecting 
  them 
  any, 
  except 
  

   in 
  trifling 
  amount 
  in 
  a 
  few 
  localities, 
  nor 
  does 
  near 
  approach 
  to 
  the 
  

   margins 
  of 
  the 
  bathylith 
  produce 
  any 
  observable 
  change 
  in 
  the 
  

   Grenville 
  rocks. 
  In 
  the 
  case 
  of 
  dikes 
  of 
  granite 
  pegmatite 
  however, 
  

   some 
  contact 
  action 
  is 
  the 
  rule, 
  coarsely 
  micaceous 
  rocks 
  being 
  the 
  

   usual 
  ones 
  produced. 
  Locally 
  the 
  mica 
  becomes 
  very 
  coarse 
  and 
  in 
  

   well 
  formed 
  crystals, 
  so 
  much 
  so 
  that 
  at 
  one 
  locality 
  north 
  of 
  

   Theresa 
  an 
  attempt 
  was 
  made 
  to 
  mine 
  it 
  commercially. 
  The 
  mica 
  

  

  