﻿THE 
  GEOLOGICAL 
  HISTORY 
  OF 
  NEW 
  YORK 
  STATE 
  

  

  35 
  

  

  large 
  masses 
  and 
  lack 
  of 
  sharply 
  defined 
  bands 
  of 
  varying 
  composi- 
  

   tion. 
  

  

  That 
  these 
  granite-syenite 
  rocks 
  are 
  younger 
  than 
  the 
  anorthosite 
  

   is 
  demonstrated 
  by 
  the 
  fact 
  that 
  tongues 
  of 
  the 
  former 
  have 
  

   been 
  observed 
  to 
  cut 
  the 
  latter 
  (see 
  figure 
  12). 
  Since 
  the 
  granite 
  

   and 
  syenite 
  now 
  visible 
  in 
  the 
  Adirondacks 
  are 
  plutonic 
  rocks, 
  they 
  

  

  Fig. 
  13 
  Geologic 
  and 
  topographic 
  sketch 
  map 
  of 
  the 
  southeastern 
  portion 
  

   of 
  the 
  North 
  Creek 
  sheet 
  (Warren 
  county), 
  showing 
  the 
  surface 
  relations 
  

   of 
  the 
  common 
  Precambric 
  rocks 
  in 
  the 
  southeastern 
  Adirondacks. 
  Con- 
  

   tour 
  interval 
  100 
  feet. 
  Horizontally 
  lined 
  areas 
  = 
  syenite 
  or 
  granite; 
  blank 
  

   areas 
  — 
  chiefly 
  Grenville 
  ; 
  small 
  heavy 
  black 
  lines 
  are 
  faults. 
  The 
  faults 
  

   here 
  shown 
  are 
  minor 
  ones 
  which 
  do 
  not 
  follow 
  the 
  NE-SW 
  trend 
  of 
  the 
  

   major 
  faults 
  of 
  the 
  eastern 
  Adirondacks. 
  The 
  so-called 
  "patch-work" 
  

   effect 
  is 
  well 
  shown. 
  Note 
  how 
  the 
  more 
  resistant 
  rocks 
  form 
  the 
  moun- 
  

   tains 
  which 
  rise 
  above 
  the 
  general 
  level 
  of 
  the 
  Grenville. 
  (W. 
  J. 
  M.) 
  

  

  could 
  not 
  have 
  reached 
  the 
  surface 
  by 
  intrusion, 
  as 
  such 
  rocks 
  can 
  

   be 
  formed 
  only 
  by 
  slow 
  cooling 
  under 
  great 
  pressure 
  thousands 
  of 
  

   feet 
  below 
  the 
  earth's 
  surface. 
  They 
  now 
  appear 
  at 
  the 
  surface 
  be- 
  

   cause 
  of 
  vast 
  removal, 
  by 
  erosion, 
  of 
  the 
  overlying 
  original 
  

   materials. 
  

   2 
  

  

  