﻿THE 
  GEOLOGICAL 
  HISTORY 
  OF 
  NEW 
  YORK 
  STATE 
  IOI 
  

  

  Iroquois. 
  We 
  know 
  that 
  the 
  old 
  Trent 
  river 
  channel 
  is 
  now 
  higher 
  

   than 
  the 
  Detroit 
  outlet, 
  but 
  some 
  of 
  the 
  proofs 
  for 
  the 
  existence 
  

   of 
  the 
  Trent 
  outlet 
  are 
  as 
  follows: 
  the 
  presence 
  there 
  of 
  a 
  large, 
  

   distinct 
  river 
  channel; 
  the 
  convergence 
  of 
  the 
  beaches 
  toward 
  that 
  

   channel; 
  and 
  the 
  fact 
  that 
  the 
  land 
  was 
  then 
  considerably 
  lower 
  on 
  

   the 
  north 
  or 
  northeast 
  side 
  of 
  Lakes 
  Ontario 
  and 
  Erie 
  than 
  on 
  the 
  

   south 
  side. 
  For 
  example, 
  in 
  following 
  the 
  old 
  Iroquois 
  beach 
  we 
  

   find 
  that 
  it 
  now 
  gradually 
  rises 
  to 
  higher 
  levels 
  until, 
  even 
  at 
  

   Watertown, 
  it 
  is 
  several 
  hundred 
  feet 
  higher 
  than 
  near 
  the 
  mouth 
  

   of 
  the 
  Niagara 
  river. 
  This 
  tilting 
  of 
  the 
  beach 
  has 
  been 
  due 
  to 
  

   raising 
  of 
  the 
  land 
  since 
  the 
  lake 
  existed, 
  and 
  it 
  is 
  evident 
  therefore 
  

   that 
  during 
  the 
  Algonquin-Iroquois 
  stage 
  the 
  Trent 
  river 
  channel 
  

   was 
  lower 
  than 
  that 
  past 
  Detroit. 
  During 
  this 
  Lake 
  Iroquois 
  stage 
  

   the 
  waters 
  of 
  all 
  the 
  Great 
  Lakes 
  region 
  discharged 
  through 
  the 
  

   Mohawk-Hudson 
  valleys, 
  and 
  the 
  volume 
  of 
  water 
  which 
  flowed 
  

   past 
  Rome, 
  Utica, 
  and 
  across 
  the 
  preglacial 
  divide 
  at 
  Little 
  Falls 
  

   must 
  have 
  been 
  as 
  great, 
  if 
  not 
  greater, 
  than 
  that 
  which 
  now 
  goes 
  

   over 
  Niagara 
  Falls. 
  Much 
  of 
  the 
  gorge 
  cutting 
  at 
  Little 
  Falls 
  was 
  

   accomplished 
  by 
  this 
  great 
  volume 
  of 
  water. 
  The 
  St 
  Lawrence 
  

   valley 
  was 
  still 
  buried 
  under 
  the 
  ice. 
  

  

  Still 
  later 
  the 
  ice 
  withdrew 
  enough 
  to 
  allow 
  the 
  Algonquin- 
  

   Iroquois 
  waters 
  to 
  discharge 
  along 
  the 
  northern 
  base 
  of 
  the 
  Adi- 
  

   rondacks 
  and 
  into 
  what 
  appears 
  to 
  have 
  been 
  ice-ponded 
  waters 
  in 
  

   the 
  Champlain 
  basin, 
  and 
  thence 
  southward 
  into 
  the 
  Hudson 
  valley. 
  

   The 
  Mohawk 
  river 
  outlet 
  was 
  thus 
  abandoned. 
  

  

  Finally 
  the 
  ice 
  retreated 
  far 
  enough 
  to- 
  free 
  the 
  St 
  Lawrence 
  

   valley 
  when 
  the 
  waters 
  of 
  the 
  Great 
  Lakes 
  region 
  dropped 
  to 
  a 
  still 
  

   lower 
  level, 
  bringing 
  about 
  the 
  Nipissing 
  Great 
  Lakes 
  stage 
  (see 
  

   figure 
  34). 
  The 
  Nipissing 
  lakes 
  found 
  a 
  low 
  outlet 
  through 
  the 
  

   Ottawa 
  river 
  (then 
  free 
  from 
  ice) 
  and 
  into 
  the 
  Champlain 
  arm 
  of 
  

   the 
  sea. 
  Postglacial 
  warping 
  of 
  the 
  land 
  brought 
  the 
  Great 
  Lakes 
  

   region 
  into 
  the 
  present 
  condition, 
  but 
  this, 
  and 
  the 
  Champlain 
  sub- 
  

   sidence, 
  being 
  really 
  postglacial 
  features 
  will 
  be 
  described 
  toward 
  

   the 
  end 
  of 
  the 
  chapter. 
  

  

  Other 
  existing 
  lakes 
  and 
  their 
  origin. 
  Counting 
  all, 
  from 
  the 
  

   smallest 
  to 
  the 
  largest, 
  there 
  are 
  within 
  the 
  borders 
  of 
  New 
  York 
  

   State 
  thousands 
  of 
  lakes, 
  which 
  constitute 
  one 
  of 
  the 
  most 
  striking 
  

   differences 
  between 
  the 
  geography 
  of 
  the 
  present 
  and 
  that 
  of 
  pre- 
  

   glacial 
  time. 
  These 
  lakes 
  are 
  widely 
  scattered 
  over 
  the 
  State 
  though 
  

   there 
  are 
  three 
  general 
  regions 
  worthy 
  of 
  particular 
  mention 
  as 
  

   follows: 
  the 
  Finger 
  lakes 
  region 
  of 
  western 
  New 
  York; 
  the 
  Adi- 
  

   rondack 
  mountains 
  ; 
  and 
  the 
  southeastern 
  portion 
  of 
  the 
  State. 
  

  

  