﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  5 
  1 
  

  

  glacial 
  period, 
  but 
  that 
  comparatively 
  little 
  erosion 
  was 
  accom- 
  

   plished. 
  This 
  is 
  farther 
  borne 
  out 
  by 
  minor 
  relief 
  features, 
  such 
  as 
  

   the 
  benches 
  shown 
  in 
  sections 
  4, 
  5 
  and 
  6, 
  in 
  the 
  southern 
  wall 
  of 
  

   the 
  basin, 
  and 
  which 
  probably 
  consist 
  of 
  harder 
  beds 
  which 
  erosion 
  

   has 
  left 
  standing 
  out 
  in 
  relief. 
  On 
  the 
  theory 
  of 
  glacial 
  erosion, 
  we 
  

   might 
  expect 
  these 
  to 
  be 
  absent, 
  or 
  at 
  least 
  much 
  less 
  prominent, 
  

   since 
  ice 
  would 
  hardly 
  show 
  such 
  selective 
  power 
  as 
  is 
  attributable 
  

   to 
  running 
  water 
  and 
  atmospheric 
  agents. 
  

  

  With 
  the 
  failures 
  of 
  the 
  theories 
  that 
  an 
  eastward 
  flowing 
  stream 
  

   or 
  glacial 
  ice 
  produced 
  the 
  Ontario 
  valley, 
  we 
  are 
  forced, 
  with 
  

   Upham, 
  Russell 
  and 
  others, 
  to 
  look 
  on 
  a 
  westward 
  flowing 
  stream 
  

   as 
  the 
  most 
  probable 
  agent 
  in 
  the 
  production 
  of 
  this 
  valley. 
  As 
  has 
  

   before 
  been 
  shown, 
  such 
  a 
  stream 
  would 
  be 
  the 
  normal 
  result 
  of 
  a 
  

   gradual 
  development 
  of 
  a 
  drainage 
  system 
  on 
  an 
  ancient 
  coastal 
  

   plain 
  of 
  the 
  type 
  here 
  considered. 
  

  

  Ancient 
  St 
  Davids 
  gorge. 
  Since 
  the 
  time 
  of 
  Lyell, 
  the 
  old 
  buried 
  

   channel 
  from 
  the 
  whirlpool 
  to 
  St 
  Davids 
  has 
  played 
  a 
  prominent 
  

   part 
  in 
  the 
  discussion 
  of 
  the 
  life 
  history 
  of 
  Niagara. 
  For 
  a 
  long- 
  

   time 
  it 
  was 
  considered 
  to 
  be 
  the 
  preglacial 
  channel 
  of 
  Niagara, 
  or 
  its 
  

   predecessor, 
  the 
  Tonawanda. 
  More 
  recently 
  it 
  has 
  been 
  considered 
  

   of 
  interglacial 
  age, 
  eroded 
  by 
  an 
  interglacial 
  Niagara, 
  during 
  a 
  tem- 
  

   porary 
  recession 
  of 
  the 
  ice 
  sheet 
  from 
  this 
  region, 
  and 
  filled 
  with 
  

   drift 
  during 
  a 
  readvance 
  of 
  the 
  glacier. 
  The 
  most 
  satisfactory 
  inter- 
  

   pretation 
  of 
  this 
  channel 
  however 
  makes 
  it 
  independent 
  of 
  the 
  

   Niagara, 
  and 
  considers 
  it 
  one 
  of 
  many 
  preglacial 
  or 
  interglacial 
  

   channels 
  which 
  were 
  formed 
  by 
  streams 
  flowing 
  over 
  the 
  edge 
  of 
  

   the 
  escarpment 
  and 
  which 
  increased 
  in 
  length 
  by 
  headward 
  gnawing 
  

   of 
  their 
  waters. 
  This 
  type 
  of 
  stream 
  we 
  have 
  learned 
  to 
  call 
  obsc- 
  

   quent, 
  its 
  direction 
  of 
  flow 
  being 
  contrary 
  to 
  that 
  of 
  the 
  master 
  

   stream 
  to 
  which 
  its 
  waters 
  eventually 
  become 
  tributary. 
  An 
  illustra- 
  

   tion 
  of 
  channel-cutting 
  by 
  streams 
  flowing 
  over 
  the 
  edge 
  of 
  a 
  clifif, 
  

   may 
  be 
  seen 
  today 
  in 
  the 
  chasm 
  near 
  the 
  Devil's 
  hole, 
  on 
  the 
  Ameri- 
  

   can 
  side 
  of 
  the 
  gorge 
  below 
  the 
  whirlpool. 
  This 
  gulch 
  was 
  cut 
  by 
  

   the 
  little 
  stream 
  known 
  as 
  the 
  Bloody 
  run, 
  which 
  during 
  the 
  sum- 
  

   mer 
  season 
  dries 
  away 
  entirely. 
  

  

  The 
  St 
  Davids 
  gorge 
  has 
  a 
  width 
  of 
  nearly 
  2 
  miles 
  at 
  the 
  edge 
  

   of 
  the 
  escarpment. 
  As 
  will 
  be 
  seen 
  by 
  a 
  glance 
  at 
  the 
  map, 
  it 
  nar- 
  

  

  