﻿I02 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  margins 
  of 
  the 
  bathylith, 
  and 
  hence 
  boxes 
  the 
  compass 
  in 
  direc- 
  

   tion. 
  At 
  the 
  same 
  time 
  the 
  rock 
  of 
  the 
  bathylith, 
  while 
  solidify- 
  

   ing, 
  may 
  develop 
  a 
  similar 
  and 
  parallel 
  foliation. 
  

  

  While 
  it 
  can 
  not 
  be 
  affirmed 
  that 
  such 
  results 
  were 
  not 
  brought 
  

   about 
  in 
  the 
  region, 
  it 
  can 
  be 
  positively 
  stated 
  that, 
  if 
  so, 
  they 
  

   have 
  been 
  so 
  disguised 
  by 
  subsequent 
  compressive 
  stresses 
  that 
  

   the 
  effects 
  of 
  the 
  two 
  can 
  not 
  now 
  be 
  successfully 
  disentangled. 
  

   This 
  is 
  shown 
  in 
  several 
  ways: 
  (a) 
  the 
  microscopic 
  study 
  of 
  the 
  

   granite 
  gneiss 
  indicates 
  that, 
  to 
  a 
  considerable 
  extent 
  at 
  least, 
  

   its 
  foliation 
  is 
  due 
  to 
  recrystallization 
  rather 
  than 
  to 
  original 
  

   crystallization, 
  in 
  other 
  words 
  the 
  rock 
  has 
  been 
  much 
  crushed 
  

   and 
  somewhat 
  recrystallized 
  under 
  compressive 
  stress, 
  since 
  it 
  

   originally 
  congealed; 
  (b) 
  these 
  later 
  stresses 
  seem 
  to 
  have 
  been 
  

   severe 
  enough 
  to 
  materially 
  change 
  the 
  shape 
  of 
  the 
  bathylithic 
  

   masses, 
  elongating 
  them 
  greatly 
  in 
  the 
  northeast-southwest 
  direction 
  

   and 
  correspondingly 
  pinching 
  them 
  together 
  in 
  the 
  direction 
  at 
  right 
  

   angles 
  to 
  this; 
  (c) 
  instead 
  of 
  the 
  foliation 
  running 
  around 
  the 
  

   bathyliths, 
  with 
  parallelism 
  to 
  the 
  margin, 
  it 
  retains 
  its 
  general 
  

   northeast-southwest 
  strike 
  throughout 
  the 
  region, 
  independendently 
  

   of 
  these 
  margins, 
  so 
  that 
  either 
  no 
  such 
  marginal 
  foliation 
  was 
  

   ever 
  developed, 
  or 
  else 
  it 
  has 
  been 
  practically 
  eliminated 
  by 
  the 
  

   subsequent 
  compression; 
  (d) 
  later 
  igneous 
  rocks 
  than 
  the 
  granite 
  

   gneiss 
  have 
  also 
  had 
  a 
  foliation 
  developed 
  as 
  a 
  result 
  of 
  com- 
  

   pression, 
  most 
  prominently 
  in 
  the 
  earlier 
  ones, 
  and 
  with 
  steady 
  

   decrease 
  in 
  prominence 
  in 
  the 
  later. 
  

  

  It 
  thus 
  appears 
  most 
  probable 
  that 
  the 
  general 
  parallelism 
  of 
  

   the 
  foliation 
  of 
  all 
  the 
  Precambric 
  rocks, 
  and 
  its 
  substantial 
  uni- 
  

   formity 
  in 
  direction 
  throughout 
  the 
  region, 
  is 
  chiefly 
  owing 
  to 
  

   compression 
  of 
  later 
  date 
  than 
  that 
  of 
  the 
  Laurentian 
  granite 
  in- 
  

   trusion. 
  This 
  appears 
  increasingly 
  true 
  in' 
  going 
  eastward 
  into, 
  

   and 
  across, 
  the 
  Adirondack 
  region. 
  The 
  rocks 
  show 
  steady 
  in- 
  

   crease 
  in 
  amount 
  of 
  metamorphism, 
  in 
  degree 
  of 
  mashing 
  and 
  re- 
  

   cr3^stallization, 
  in 
  uniformity 
  of 
  foliation, 
  and 
  in 
  obliteration 
  of 
  

   such 
  possible 
  structures 
  as 
  primary 
  foliation. 
  Some 
  of 
  this 
  in- 
  

   crease 
  may 
  be 
  ascribable 
  to 
  greater 
  thickness 
  of 
  cover, 
  but 
  the 
  

   evidence 
  of 
  thoroughgoing 
  compression 
  of 
  much 
  later 
  date 
  than 
  

   the 
  Laurentian, 
  is 
  very 
  clear. 
  

  

  Foliation 
  of 
  the 
  later 
  igneous 
  rocks. 
  The 
  Alexandria 
  and 
  

   Theresa 
  syenites 
  seem 
  closest 
  to 
  the 
  Laurentian 
  in 
  age, 
  among 
  

   the 
  conspicuous 
  igneous 
  rocks 
  of 
  the 
  district. 
  The 
  Alexandria 
  

   syenite 
  shows 
  cores 
  of 
  fairly 
  massive 
  rock, 
  not 
  foliated 
  though 
  

   with 
  a 
  considerable 
  amount 
  of 
  crushing. 
  But 
  the 
  porphyritic 
  

  

  