﻿THE 
  GEOLOGICAL 
  HISTORY 
  OF 
  NEW 
  YORK 
  STATE 
  8l 
  

  

  territory 
  at 
  the 
  expense 
  of 
  the 
  Susquehanna 
  because 
  the 
  short, 
  

   swift 
  tributaries 
  of 
  the 
  Mohawk, 
  which 
  flow 
  northward 
  over 
  the 
  

   Helderberg 
  escarpment, 
  are 
  cutting 
  down 
  their 
  channels 
  rapidly, 
  

   while 
  their 
  headwaters 
  are 
  migrating 
  southward 
  into 
  the 
  territory 
  

   of 
  the 
  Susquehanna. 
  A 
  great 
  network 
  of 
  large 
  and 
  small 
  streams 
  

   tributary 
  to 
  the 
  upper 
  Susquehanna 
  drain 
  a 
  considerable 
  portion 
  of 
  

   south-central 
  New 
  York, 
  there 
  being 
  no 
  single 
  great 
  master 
  stream 
  

   in 
  this 
  region 
  because 
  the 
  rock 
  formations 
  are 
  so 
  nearly 
  horizontal 
  

   and 
  are 
  so 
  much 
  alike 
  as 
  regards 
  resistance 
  to 
  erosion. 
  

  

  The 
  Delaware 
  system 
  has 
  had 
  a 
  history 
  practically 
  the 
  same 
  as 
  

   that 
  of 
  the 
  Susquehanna, 
  except 
  that 
  it 
  never 
  drained 
  any 
  of 
  the 
  

   region 
  north 
  of 
  the 
  Mohawk. 
  

  

  The 
  present 
  ruggedness 
  of 
  the 
  Catskills 
  is 
  largely, 
  if 
  not 
  alto- 
  

   gether, 
  due 
  to 
  the 
  production 
  of 
  deep 
  channels 
  which 
  have 
  been 
  

   cut 
  into 
  the 
  region 
  upraised 
  at 
  the 
  time 
  of 
  the 
  uplift 
  of 
  the 
  great 
  

   peneplain 
  by 
  the 
  headwaters 
  of 
  the 
  Delaware, 
  Schoharie 
  creek 
  

   (north-flowing), 
  and 
  the 
  smaller 
  streams 
  flowing 
  across 
  the 
  steep 
  

   eastern 
  front 
  of 
  the 
  mountains. 
  

  

  During 
  Tertiary 
  times 
  Lake 
  Champlain 
  was 
  certainly 
  not 
  in 
  

   existence, 
  but 
  the 
  great 
  depression 
  was 
  there 
  and 
  was 
  no- 
  doubt 
  

   largely 
  developed 
  or 
  at 
  least 
  increased 
  in 
  depth 
  by 
  the 
  settling 
  of 
  

   earth 
  blocks 
  during 
  the 
  time 
  of 
  extensive 
  faulting 
  at 
  the 
  close 
  of 
  

   the 
  Mesozoic 
  or 
  beginning 
  of 
  the 
  Cenozoic. 
  The 
  depression 
  is 
  

   essentially 
  a 
  fault 
  trough. 
  The 
  major 
  stream 
  occupying 
  this 
  valley 
  

   flowed 
  northward 
  and 
  in 
  late 
  Tertiary 
  time, 
  at 
  least, 
  the 
  divide 
  

   between 
  the 
  drainage 
  of 
  this 
  and 
  the 
  Hudson 
  valley 
  passed 
  between 
  

   Glens 
  Falls 
  and 
  Whitehall, 
  and 
  through 
  the 
  present 
  position 
  of 
  

   the 
  " 
  Narrows 
  " 
  of 
  Lake 
  George, 
  the 
  lake, 
  of 
  course, 
  not 
  then 
  being 
  

   in 
  existence. 
  

  

  Drainage 
  of 
  New 
  York 
  in 
  the 
  Tertiary. 
  The 
  outline 
  of 
  the 
  

   probable 
  drainage 
  condition 
  of 
  western 
  New 
  York 
  during 
  the 
  

   Mesozoic 
  has 
  already 
  been 
  given, 
  and 
  now 
  as 
  we 
  attempt 
  to 
  restore 
  

   the 
  drainage 
  conditions 
  of 
  the 
  Tertiary, 
  we 
  must 
  admit 
  that 
  some 
  

   problems 
  yet 
  remain 
  unsolved. 
  Lakes 
  Ontario 
  and 
  Erie 
  certainly 
  

   were 
  not 
  in 
  existence. 
  Streams 
  flowed 
  through 
  these 
  basins, 
  which 
  

   were 
  not 
  as 
  deep 
  as 
  they 
  now 
  are. 
  The 
  bottom 
  of 
  Ontario 
  is 
  as 
  

   much 
  as 
  491 
  feet 
  below 
  sea 
  level, 
  while 
  its 
  surface 
  lies 
  at 
  an 
  alti- 
  

   tude 
  of 
  247 
  feet, 
  and 
  the 
  altitude 
  of 
  Erie 
  is 
  573 
  feet 
  while 
  its 
  

   greatest 
  depth 
  is 
  204 
  feet. 
  The 
  explanation 
  of 
  the 
  increased 
  depths 
  

   of 
  the 
  basins 
  is 
  given 
  on 
  a 
  later 
  page. 
  The 
  question 
  now 
  arises, 
  Did 
  

   the 
  waters 
  from 
  western 
  New 
  York 
  drain 
  westward 
  or 
  southwest- 
  

   ward 
  and 
  into 
  the 
  Mississippi, 
  or 
  northeastward 
  through 
  the 
  St 
  

  

  