﻿42 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  ning 
  northward 
  at 
  a 
  rate 
  proportional 
  to 
  the 
  dip 
  of 
  the 
  beds. 
  The 
  

   ultimate 
  result 
  of 
  all 
  this 
  erosion 
  was 
  the 
  reduction 
  of 
  the 
  land 
  to 
  a 
  

   low 
  peneplain, 
  which 
  did 
  not 
  rise 
  much 
  above 
  the 
  sealevel. 
  Por- 
  

   tions 
  of 
  this 
  peneplain 
  are 
  today 
  preserved 
  in 
  a 
  scarcely 
  altered 
  con- 
  

   dition, 
  in 
  the 
  Niagara 
  upland, 
  the 
  region 
  about 
  Buffalo 
  and 
  other 
  

   localities. 
  The 
  slight 
  change 
  which 
  these 
  regions 
  have 
  subse- 
  

   quently 
  undergone 
  leads 
  to 
  the 
  supposition 
  that 
  the 
  peneplain 
  was 
  

   completed 
  in 
  comparatively 
  recent 
  geologic 
  time, 
  possibly 
  at 
  the 
  

   beginning 
  of 
  the 
  Tertiary 
  era, 
  or 
  even 
  more 
  recently. 
  This 
  is 
  also 
  

   shown 
  by 
  the 
  comparative 
  narrowness 
  of 
  the 
  valleys 
  cut 
  into 
  the 
  

   peneplain 
  surface 
  in 
  preglacial 
  times. 
  The 
  present 
  altitude 
  of 
  this 
  

   peneplain 
  in 
  the 
  vicinity 
  of 
  the 
  Niagara 
  river 
  is 
  approximately 
  600 
  

   feet 
  above 
  sealevel, 
  while 
  southward 
  it 
  rises. 
  There 
  is 
  however 
  

   good 
  presumptive 
  evidence, 
  some 
  of 
  which 
  will 
  be 
  detailed 
  later, 
  

   that, 
  during 
  a 
  period 
  preceding 
  the 
  glacial 
  epoch, 
  the 
  land 
  in 
  the 
  

   north 
  stood 
  much 
  higher 
  than 
  at 
  present, 
  so 
  that 
  the 
  slope 
  of 
  the 
  

   surface 
  was 
  southward. 
  An 
  accentuation 
  of 
  slope 
  would 
  cause 
  a 
  

   rejuvenation 
  of 
  the 
  consequent 
  streams, 
  which, 
  in 
  the 
  later 
  stages 
  

   of 
  peneplanation, 
  had 
  practically 
  ceased 
  their 
  work 
  of 
  erosion 
  on 
  ac- 
  

   count 
  of 
  the 
  low 
  gradient 
  of 
  the 
  land. 
  As 
  a 
  result 
  of 
  the 
  renewal 
  

   of 
  erosive 
  activity 
  the 
  early 
  Mesozoic 
  topography 
  was 
  in 
  a 
  large 
  

   measure 
  restored, 
  but 
  the 
  inface 
  of 
  the 
  Niagara 
  cuesta, 
  the 
  top 
  of 
  

   which 
  is 
  now 
  found 
  in 
  the 
  Niagara 
  escarpment, 
  occupied 
  in 
  the 
  re- 
  

   stored 
  topography 
  a 
  position 
  considerably 
  farther 
  to 
  the 
  south 
  than 
  

   that 
  characteristic 
  of 
  early 
  Mesozoic 
  time. 
  

  

  We 
  may 
  now 
  examine 
  more 
  in 
  detail 
  the 
  channels 
  of 
  the 
  conse- 
  

   quent 
  streams 
  which 
  dissected 
  this 
  ancient 
  coastal 
  plain, 
  and 
  the 
  ex- 
  

   tent 
  of 
  the 
  inner 
  lowlands 
  drained 
  by 
  the 
  subsequent 
  streams 
  tribu- 
  

   tary 
  to 
  them. 
  

  

  Dundas 
  valley. 
  The 
  Dundas 
  valley 
  appears 
  to 
  have 
  been 
  the 
  out- 
  

   let 
  for 
  the 
  master 
  consequent 
  stream 
  of 
  this 
  region, 
  the 
  Dundas 
  

   river. 
  This 
  valley, 
  as 
  before 
  noted, 
  breaches 
  the 
  escarpment 
  at 
  

   Hamilton 
  (Ont.), 
  near 
  the 
  extreme 
  western 
  end 
  of 
  Lake 
  Ontario. 
  

   The 
  valley 
  has 
  been 
  carefully 
  described 
  by 
  Spencer, 
  who 
  considered 
  

   it 
  the 
  pathway 
  of 
  the 
  preglacial 
  outlet 
  of 
  Lake 
  Erie 
  into 
  Lake 
  On- 
  

   tario, 
  the 
  drainage 
  of 
  the 
  Erie 
  valley 
  being 
  in 
  his 
  opinion 
  by 
  a 
  

  

  