﻿70 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  The 
  Mohawk 
  and 
  upper 
  Hudson 
  valleys 
  have 
  been 
  so 
  broadly 
  

   and 
  deeply 
  trenched 
  through 
  soft 
  strata 
  that 
  in 
  them 
  no 
  remnants 
  

   of 
  the 
  peneplain 
  surface 
  remain. 
  Immediately 
  eastward 
  in 
  the 
  

   Berkshires, 
  however, 
  the 
  old 
  surface 
  is 
  well 
  exhibited. 
  In 
  the 
  

   Highlands-of-the-Hudson, 
  a 
  view 
  from 
  one 
  of 
  the 
  high 
  points 
  

   shows 
  a 
  rather 
  even 
  sky 
  line 
  at 
  an 
  altitude 
  of 
  from 
  1200 
  to 
  1500 
  

   feet, 
  the 
  somewhat 
  lower 
  elevation 
  of 
  the 
  old 
  surface 
  here 
  being 
  

   due 
  to 
  the 
  fact 
  that 
  this 
  region 
  was 
  east 
  of 
  the 
  main 
  axis 
  of 
  uplift. 
  

  

  Since 
  the 
  actual 
  work 
  of 
  erosion 
  or 
  dissection 
  of 
  the 
  upraised 
  

   peneplain 
  occurred 
  during 
  the 
  Cenozoic 
  era, 
  further 
  discussion 
  of 
  

   the 
  subject 
  is 
  reserved 
  for 
  the 
  next 
  chapter. 
  It 
  has 
  been 
  the 
  present 
  

   purpose 
  to 
  prove 
  that 
  the 
  Cretacic 
  peneplain 
  actually 
  existed 
  and 
  

   that 
  it 
  was 
  upraised. 
  

  

  FAULTING 
  OF 
  THE 
  EASTERN 
  ADIRONDACKS 
  

  

  The 
  eastern 
  and 
  Southern 
  Adirondack 
  regions 
  have 
  been 
  exten- 
  

   sively 
  fractured 
  or 
  faulted 
  (see 
  figures 
  23 
  and 
  21^). 
  In 
  fact 
  the 
  

   major 
  topographic 
  features 
  of 
  those 
  regions 
  such 
  as 
  the 
  numerous 
  

   north-northeast 
  by 
  south-southzvcsi 
  ridges 
  and 
  valleys 
  are 
  largely 
  

  

  Fig. 
  23 
  Cross-section 
  of 
  a 
  normal 
  

   fault. 
  

  

  Fig. 
  24 
  Cross-section 
  of 
  a 
  reversed 
  

   or 
  thrust 
  fault. 
  

  

  dependent 
  upon 
  this 
  faulted 
  structure. 
  These 
  fractures 
  are 
  all 
  of 
  the 
  

   normal 
  fault 
  type 
  with 
  fault 
  surfaces 
  practically 
  vertical. 
  Examina- 
  

   tion 
  of 
  the 
  topographic 
  maps 
  of 
  the 
  whole 
  eastern 
  and 
  southern 
  Adi- 
  

   rondacks 
  shows 
  that 
  by 
  far 
  most 
  of 
  the 
  ridges 
  and 
  valleys, 
  streams 
  

   and 
  lakes 
  trend 
  in 
  a 
  north-northeast 
  by 
  south-southwest 
  direction, 
  

   or 
  perfectly 
  parallel 
  to 
  the 
  direction 
  of 
  the 
  major 
  faults. 
  Up 
  to 
  

   the 
  present, 
  no 
  single 
  fault 
  has 
  been 
  proved 
  to 
  extend 
  across 
  the 
  

   entire 
  region, 
  but 
  rather 
  there 
  is 
  a 
  series 
  of 
  numerous 
  parallel 
  faults, 
  

   no 
  one 
  of 
  which 
  has 
  been 
  traced 
  much 
  over 
  20 
  or 
  30 
  miles". 
  The 
  

   exact 
  amount 
  of 
  displacement 
  along 
  these 
  lines 
  of 
  fracture 
  in 
  the 
  

   ancient 
  crystalline 
  rocks 
  can 
  not 
  be 
  determined, 
  but 
  many 
  times 
  it 
  

   amounts 
  to 
  at 
  least 
  2000 
  feet. 
  

  

  