﻿52 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  rows 
  perceptibly 
  southward, 
  till 
  at 
  the 
  whirlpool 
  its 
  width 
  is 
  less 
  

   than 
  the 
  average 
  width 
  of 
  the 
  Niagara 
  gorge. 
  What 
  the 
  depth 
  of 
  

   the 
  gorge 
  is 
  has 
  not 
  been 
  determined, 
  though 
  from 
  the 
  depth 
  of 
  

   the 
  whirlpool, 
  we 
  may 
  assume 
  that 
  its 
  floor 
  is 
  200 
  feet 
  or 
  more 
  be- 
  

   low 
  the 
  level 
  of 
  Lake 
  Ontario. 
  At, 
  and 
  to 
  the 
  north 
  of 
  the 
  escarp- 
  

   ment 
  it 
  probably 
  equals 
  in 
  depth 
  Lake 
  Ontario, 
  opposite 
  to 
  it. 
  The 
  

   channel 
  is 
  undoubtedly 
  much 
  more 
  irregular 
  than 
  is 
  shown 
  on 
  the 
  

   map, 
  the 
  sides 
  being 
  probably 
  much 
  diversified 
  by 
  lateral 
  gullies. 
  

   The 
  great 
  width 
  of 
  the 
  channel 
  at 
  St 
  Davids 
  may 
  perhaps 
  be 
  due 
  

   in 
  some 
  small 
  degree 
  to 
  widening 
  by 
  glacial 
  erosion; 
  for 
  we 
  know 
  

   that 
  the 
  channel 
  was 
  occupied 
  by 
  ice, 
  from 
  the 
  glacial 
  scratches 
  

   which 
  are 
  preserved 
  on 
  its 
  walls, 
  where 
  these 
  are 
  exposed 
  in 
  the 
  

   present 
  ravine 
  of 
  Bowman's 
  creek 
  near 
  the 
  whirlpool. 
  The 
  influence 
  

   of 
  this 
  buried 
  channel 
  on 
  the 
  direction 
  and 
  width 
  of 
  the 
  Niagara 
  

   gorge 
  will 
  be 
  discussed 
  later. 
  

  

  Valley 
  of 
  Georgian 
  bay. 
  Georgian 
  bay 
  is 
  in 
  many 
  respects 
  the 
  

   analogue 
  of 
  Lake 
  Ontario. 
  Like 
  the 
  latter, 
  it 
  also 
  occupies 
  a 
  valley 
  

   lying 
  between 
  the 
  Niagara 
  escarpment 
  and 
  the 
  crystalhne 
  old-land 
  

   on 
  the 
  northeast. 
  As^ 
  has 
  previously 
  been 
  shown, 
  the 
  Niagara 
  es- 
  

   carpment 
  extends 
  northward 
  from 
  Hamilton 
  into 
  the 
  Indian 
  penin- 
  

   sula 
  between 
  Georgian 
  bay 
  and 
  Lake 
  Huron, 
  and, 
  after 
  passing 
  the 
  

   Cove 
  island 
  channel, 
  it 
  reappears 
  in 
  the 
  northwestern 
  face 
  of 
  Grand 
  

   Manitoulin 
  island. 
  At 
  Cabot's 
  head, 
  on 
  the 
  Indian 
  peninsula, 
  the 
  

   escarpment 
  rises 
  to 
  324 
  feet 
  above 
  the 
  surface 
  of 
  the 
  water, 
  while 
  

   just 
  off 
  the 
  promontory 
  soundings 
  show 
  a 
  depth 
  of 
  510 
  feet, 
  thus 
  

   making 
  the 
  total 
  hight 
  of 
  the 
  escarpment 
  at 
  this 
  point 
  834 
  feet. 
  In 
  

   some 
  places 
  the 
  summit 
  of 
  the 
  escarpment 
  rises 
  to 
  an 
  elevation 
  of 
  

   1700 
  feet 
  above 
  tide, 
  or 
  more 
  than 
  iioo 
  feet 
  above 
  Georgian 
  bay 
  

   (Spencer). 
  The 
  depth 
  of 
  the 
  transverse 
  channel 
  connecting 
  Georgian 
  

   bay 
  and 
  Lake 
  Huron 
  has 
  been 
  found 
  to 
  be 
  306 
  feet, 
  which 
  is 
  more 
  

   than 
  200 
  feet 
  less 
  than 
  the 
  depth 
  of 
  the 
  channel 
  of 
  Georgian 
  bay. 
  

   It 
  is 
  possible 
  however 
  that 
  the 
  soundings 
  do 
  not 
  show 
  the 
  absolute 
  

   depth 
  of 
  the 
  rock 
  bottom 
  in 
  the 
  channel; 
  for 
  there 
  may 
  be 
  a 
  filling 
  

   of 
  drift 
  which 
  raised 
  the 
  bottom 
  of 
  the 
  channel 
  above 
  that 
  of 
  the 
  

   bav. 
  

  

  