﻿76 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Other 
  by 
  the 
  Hmestone 
  of 
  the 
  CHnton 
  group, 
  and 
  a 
  third 
  by 
  the 
  

   Lockport 
  Hmestone. 
  In 
  the 
  Niagara 
  river 
  we 
  might 
  suppose 
  that 
  

   at 
  least 
  three, 
  and 
  possibly 
  four, 
  falls 
  had 
  existed 
  at 
  one 
  time. 
  The 
  

   lowest 
  of 
  these 
  would 
  have 
  been 
  over 
  aMiard 
  bed 
  of 
  sandstone, 
  

   about 
  25 
  feet 
  thick, 
  and 
  about 
  100 
  feet 
  below 
  the 
  top 
  of 
  the 
  Medina 
  

   group. 
  Another 
  might 
  have 
  been 
  caused 
  by 
  the 
  hard 
  capping 
  

   stratum 
  of 
  Medina 
  sandstone, 
  10 
  feet 
  thick. 
  A 
  third 
  over 
  the 
  30 
  

   feet 
  of 
  Clinton 
  limestone 
  ; 
  while 
  a 
  fourth 
  would 
  have 
  been 
  formed 
  

   over 
  the 
  Lockport 
  limestone. 
  The 
  second 
  and 
  third 
  would- 
  per- 
  

   haps 
  unite 
  in 
  one, 
  as 
  the 
  shale 
  bed 
  between 
  the 
  two 
  resistant 
  layers 
  

   is 
  only 
  6 
  feet 
  thick. 
  It 
  may 
  however 
  be 
  objected 
  that 
  in 
  a 
  great 
  

   cataract 
  the 
  force 
  of 
  the 
  falling 
  water 
  is 
  such 
  as 
  to 
  cause 
  uniform 
  

   recession 
  of 
  all 
  the 
  layers^ 
  and 
  that 
  hence 
  only 
  one 
  great 
  fall 
  existed. 
  

  

  The 
  whirlpool 
  

  

  PLATE 
  9 
  

  

  Perhaps 
  the 
  most 
  remarkable 
  part 
  of 
  the 
  entire 
  gorge 
  is 
  its 
  great 
  

   swollen 
  elbow, 
  the 
  whirlpool. 
  Here 
  the 
  current 
  rushing 
  in 
  from 
  the 
  

   southeast 
  with 
  great 
  velocity, 
  circles 
  around 
  the 
  basin 
  and 
  finally 
  

   escapes, 
  by 
  passing 
  under 
  the 
  incoming 
  current, 
  through 
  the 
  com- 
  

   paratively 
  narrow 
  outlet, 
  in 
  a 
  northeasterly 
  direction. 
  The 
  waters 
  

   in 
  the 
  whirlpool 
  have 
  probably 
  a 
  depth 
  of 
  150 
  or 
  200 
  feet, 
  but 
  

   both 
  the 
  outlet 
  and 
  the 
  inlet 
  are 
  shallow, 
  for 
  here 
  ledges 
  of 
  the 
  

   hard 
  quartzose 
  bed 
  of 
  the 
  Medina 
  formation 
  project 
  into 
  the 
  river, 
  

   extending 
  in 
  the 
  latter 
  case 
  probably 
  across 
  the 
  channel. 
  An 
  ex- 
  

   amination 
  of 
  the 
  walls 
  of 
  the 
  whirlpool 
  basin 
  shows 
  that 
  rock 
  is 
  

   absent 
  on 
  its 
  northwestern 
  side, 
  the 
  wall 
  here 
  being 
  formed 
  of 
  un- 
  

   consoHdated 
  material 
  or 
  drift. 
  This 
  is 
  best 
  seen 
  on 
  descending 
  to- 
  

   the 
  edge 
  of 
  the 
  whirlpool 
  on 
  the 
  Canadian 
  side, 
  through 
  the 
  ravine 
  

   of 
  Bowmans 
  creek. 
  It 
  will 
  be 
  observed 
  that 
  the 
  Niagara 
  has 
  here 
  

   exposed 
  a 
  cross-section 
  of 
  the 
  ancient 
  drift-filled 
  channel 
  which 
  ex- 
  

   tends 
  southeastward 
  from 
  St 
  Davids. 
  This 
  channel 
  appears 
  to 
  have 
  

   been 
  that 
  of 
  a 
  preglacial 
  stream 
  of 
  the 
  obsequent 
  type,^ 
  which 
  was 
  

   tributary 
  to 
  the 
  streams 
  of 
  the 
  Ontario 
  lowland. 
  Some 
  geologists 
  

   however, 
  notably 
  Mr 
  Taylor, 
  believe 
  that 
  this 
  old 
  channel 
  may 
  have 
  

  

  ^See 
  chapter 
  i. 
  

  

  