﻿CRYSTALLINE 
  ROCKS 
  OP 
  THE 
  WESTERN 
  ADIRONDACK 
  REGION 
  493 
  

  

  presence 
  of 
  quite 
  an 
  extensive 
  belt 
  of 
  the 
  limestone 
  formation 
  

   which 
  should 
  be 
  traced 
  in 
  detail. 
  

  

  Rocky 
  point 
  and 
  Goethe's 
  point 
  at 
  the 
  head 
  of 
  Fourth 
  lake 
  pre- 
  

   sent 
  a 
  variety 
  of 
  the 
  limestone 
  totally 
  different 
  from 
  any 
  that 
  

   the 
  writer 
  has- 
  elsewhere 
  seen. 
  The 
  limestone 
  with 
  associated 
  

   gray 
  and 
  rusty 
  gneisses 
  occupies 
  only 
  a 
  small 
  area 
  and 
  might 
  

   easily 
  be 
  overlooked 
  did 
  it 
  not 
  form 
  the 
  shore 
  of 
  the 
  lake 
  for 
  a 
  

   short 
  distance. 
  On 
  a 
  weathered 
  surface 
  the 
  rock 
  presents 
  at 
  first 
  

   glance 
  a 
  marked 
  resemblance 
  to 
  a 
  fine 
  conglomerate, 
  with 
  the 
  

   pebbles 
  projecting 
  above 
  the 
  more 
  yielding 
  cement. 
  But 
  on 
  

   closer 
  inspection 
  the 
  pebbles 
  resolve 
  themselves 
  into 
  crystals 
  of 
  

   feldspar 
  from 
  a 
  quarter 
  of 
  an 
  inch 
  up 
  to 
  one 
  or 
  two 
  inches 
  in 
  

   diameter, 
  while 
  the 
  cement 
  is 
  fine 
  crystalline 
  limestone 
  contain- 
  

   ing 
  much 
  pyroxene. 
  < 
  

  

  It 
  is 
  evident 
  that 
  the 
  feldspars 
  are 
  not 
  residual 
  but 
  a 
  product 
  

   of 
  crystallization 
  in 
  situ. 
  For 
  not 
  only 
  can 
  no 
  foreign 
  source 
  be 
  

   discovered 
  for 
  them, 
  but 
  their 
  angular 
  form, 
  unity 
  of 
  character 
  

   and 
  relation 
  to 
  other 
  minerals 
  show 
  their 
  autogenic 
  nature. 
  The 
  

   limestone 
  also 
  shows 
  large 
  angular 
  and 
  rounded 
  masses 
  of 
  

   schist 
  and 
  pyroxene 
  gneiss 
  scattered 
  through 
  it, 
  which 
  further 
  

   recall 
  the 
  appearance 
  of 
  some 
  conglomerates. 
  But 
  it 
  is 
  evident 
  

   that 
  these 
  fragments 
  are 
  identical 
  with 
  the 
  schists 
  and 
  gneisses 
  

   of 
  the 
  limestone 
  formation 
  itself, 
  and 
  when 
  the 
  breccias 
  and 
  

   pseudo-conglomerates 
  of 
  the 
  limestone 
  of 
  St 
  Lawrence 
  co. 
  are 
  

   recalled, 
  it 
  is 
  clear 
  that 
  this 
  is 
  an 
  extreme 
  case 
  of 
  the 
  same 
  kind. 
  

   The 
  formation 
  has 
  been 
  subjected 
  to 
  pressure 
  sufficient 
  to 
  crush 
  

   the 
  imbedded 
  gneisses 
  and 
  schists 
  and 
  mingle 
  the 
  fragments 
  with 
  

   the 
  flowing, 
  putty-like 
  limestone. 
  

  

  The 
  appearance 
  of 
  the 
  feldspathic 
  limestone 
  is 
  shown 
  iu 
  

   plate 
  8. 
  The 
  peculiar 
  " 
  pebbly 
  " 
  aspect 
  is 
  evident, 
  while 
  at 
  the 
  

   same 
  time 
  the 
  very 
  characteristic 
  surface 
  produced 
  by 
  weather- 
  

   ing 
  is 
  quite 
  as 
  apparent 
  as 
  in 
  a 
  normal 
  crystalline 
  limestone. 
  

   The 
  pseudo-conglomerate 
  is 
  shown 
  in 
  plate 
  9, 
  which 
  also 
  affords 
  

   a 
  nearer 
  view 
  of 
  the 
  feldspathic 
  limestone. 
  

  

  In 
  addition 
  to 
  the 
  peculiar 
  feldspathic 
  limestone 
  described 
  

   there 
  is 
  a 
  good 
  exposure 
  of 
  typical 
  limestone 
  associated 
  with 
  

  

  