﻿CRYSTALLINE 
  ROCKS 
  OF 
  THE 
  WESTERN 
  ADIRONDACK 
  REGION 
  481 
  

  

  marked 
  degree 
  as 
  foliation 
  becomes 
  more 
  perfect 
  indicates 
  that 
  

   the 
  latter 
  is 
  a 
  product 
  of 
  crushing 
  subsequent 
  to 
  solidification. 
  

  

  Nevertheless 
  the 
  writer 
  is 
  inclined 
  to 
  think 
  that 
  flow 
  structure 
  

   is 
  also 
  present, 
  though 
  the 
  secondary 
  structure 
  has 
  made 
  it 
  dif- 
  

   ficult 
  to 
  prove 
  that 
  such 
  is 
  the 
  case 
  except 
  in 
  some 
  minor 
  in- 
  

   stances 
  like 
  that 
  connected 
  with 
  the 
  inclusions 
  first 
  described. 
  

  

  It 
  is 
  the 
  fact 
  that 
  this 
  rock 
  of 
  wide 
  exent 
  is 
  distinctly 
  gneissoid 
  

   and 
  yet 
  shows 
  its 
  origin 
  clearly 
  that 
  has 
  led 
  the 
  writer 
  to 
  deal 
  

   with 
  it 
  at 
  such 
  length; 
  for 
  the 
  western 
  Adirondack 
  region 
  is 
  

   largely 
  made 
  up 
  of 
  gneisses 
  which 
  have 
  much 
  in 
  common 
  with 
  

   this 
  rock, 
  and 
  any 
  localities 
  where 
  determinate 
  structural 
  data 
  

   are 
  available 
  demand 
  close 
  study, 
  much 
  closer 
  indeed 
  than 
  has 
  

   yet 
  been 
  given 
  in 
  any 
  instance. 
  So 
  far 
  as 
  the 
  studies 
  have 
  been 
  

   carried 
  on 
  the 
  only 
  rocks 
  found 
  which 
  closely 
  resemble 
  the 
  great 
  

   areas 
  of 
  gneiss 
  and 
  whose 
  origin 
  is 
  fairly 
  clear 
  are 
  those 
  which 
  

   are 
  certainly 
  or 
  probably 
  of 
  igneous 
  origin. 
  On 
  the 
  other 
  hand, 
  

   the 
  gneisses 
  which 
  from 
  their 
  mode 
  of 
  occurrence, 
  structure 
  and 
  

   composition 
  are 
  almost 
  certainly 
  of 
  sedimentary 
  origin 
  are 
  very 
  

   different 
  as 
  a 
  class 
  from 
  the 
  gneisses 
  of 
  the 
  large 
  areas 
  above 
  

   referred 
  to. 
  

  

  The 
  bearing 
  of 
  these 
  facts 
  and 
  the 
  inferences 
  to 
  which 
  they 
  lead 
  

   have 
  been 
  discussed 
  in 
  a 
  previous 
  report. 
  But 
  while 
  the 
  con- 
  

   clusion 
  that 
  some 
  of 
  the 
  gneisses 
  are 
  certainly 
  and 
  most 
  of 
  them 
  

   probably 
  igneous 
  seems 
  fully 
  justified 
  in 
  the 
  present 
  state 
  of 
  the 
  

   inquiry, 
  the 
  writer 
  constantly 
  endeavors 
  not 
  to 
  give 
  undue 
  prom- 
  

   inence 
  to 
  this 
  view 
  in 
  dealing 
  with 
  the 
  facts 
  in 
  hand. 
  It 
  is 
  

   adopted 
  as 
  a 
  finality 
  only 
  when, 
  as 
  in 
  the 
  case 
  under 
  discussion 
  

   and 
  in 
  others 
  previously 
  described, 
  it 
  affords 
  a 
  rational 
  explana- 
  

   tion 
  of 
  phenomena 
  that 
  can 
  be 
  correlated 
  and 
  accounted 
  for 
  by 
  

   no 
  other 
  hypothesis. 
  

  

  The 
  southern 
  margin 
  of 
  the 
  syenite 
  is 
  much 
  less 
  clearly 
  defined 
  

   than 
  is 
  its 
  northern 
  margin 
  where 
  it 
  comes 
  in 
  contact 
  with 
  the 
  

   limestone 
  formation. 
  Passing 
  southward 
  from 
  the 
  latter 
  the 
  

   syenite 
  at 
  first 
  slowly 
  and 
  irregularly 
  then 
  more 
  rapidly 
  in- 
  

   creases 
  in 
  gneissoid 
  structure 
  till 
  at 
  a 
  distance 
  of 
  from 
  three 
  to 
  

   five 
  miles 
  from 
  the 
  limestone 
  a 
  region 
  of 
  red 
  hornblende 
  gneiss 
  is 
  

  

  