﻿84 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  The 
  former 
  makes 
  the 
  age 
  of 
  the 
  gorge 
  in 
  round 
  numbers 
  32,000 
  

   years, 
  the 
  latter 
  places 
  it 
  tentatively 
  at 
  50,000 
  years, 
  though 
  recog- 
  

   nizing 
  the 
  uncertainty 
  of 
  many 
  of 
  the 
  elements 
  which 
  enter 
  into 
  his 
  

   calculations. 
  Prof. 
  G. 
  F. 
  Wright 
  has 
  recently 
  applied 
  a 
  most 
  in- 
  

   genious 
  method 
  to 
  the 
  solution 
  of 
  this 
  question, 
  and 
  one 
  which 
  

   seems 
  to 
  eliminate 
  the 
  doubtful 
  factors.^ 
  This 
  method 
  is 
  based 
  on 
  

   the 
  measured 
  rate 
  of 
  enlargement 
  of 
  the 
  oldest 
  part 
  of 
  the 
  gorge 
  by 
  

   atmospheric 
  action. 
  The 
  present 
  width 
  of 
  the 
  river 
  at 
  the 
  mouth 
  

   of 
  the 
  gorge 
  is 
  770 
  feet, 
  and 
  Prof. 
  Wright 
  thinks 
  that 
  it 
  was 
  probably 
  

   not 
  less 
  at 
  the 
  time 
  when 
  the 
  formation 
  of 
  the 
  gorge 
  began. 
  

   Assuming 
  that 
  the 
  bank 
  at 
  that 
  time 
  was 
  vertical, 
  he 
  finds 
  

   that 
  since 
  then 
  the 
  stratum 
  of 
  Lockport 
  limestone 
  at 
  the 
  top 
  

   has 
  retreated 
  388 
  feet. 
  Careful 
  measurements 
  show 
  that 
  the 
  

   total 
  amount 
  of 
  work 
  accomplished 
  here 
  by 
  the 
  atmosphere 
  

   since 
  the 
  beginning 
  of 
  gorge 
  formation, 
  was 
  the 
  removal 
  from 
  

   the 
  side 
  of 
  the 
  gorge 
  of 
  a 
  mass 
  of 
  rock 
  constituting 
  in 
  section 
  

   an 
  inverted 
  triangle 
  340 
  feet 
  high 
  and 
  with 
  a 
  base 
  of 
  388 
  feet. 
  This 
  

   would 
  be 
  similar 
  to 
  a 
  mass 
  with 
  a 
  rectangular 
  section 
  of 
  the 
  same 
  

   hight 
  but 
  with 
  a 
  base 
  194 
  feet 
  wide. 
  The 
  rate 
  of 
  waste 
  of 
  the 
  

   banks 
  was 
  measured 
  by 
  Prof. 
  Wright 
  as 
  accurately 
  as 
  possible 
  and 
  

   found 
  to 
  be 
  over 
  one 
  fourth 
  of 
  an 
  inch 
  a 
  year, 
  or 
  a 
  total 
  amount 
  of 
  

   610 
  cubic 
  yards 
  of 
  rock 
  from 
  one 
  mile 
  of 
  the 
  gorge 
  wall. 
  From 
  this 
  

   he 
  finds 
  that 
  10,000 
  years 
  is 
  the 
  maximum 
  amount 
  of 
  time 
  required 
  

   for 
  the 
  entire 
  change 
  which 
  has 
  occurred 
  in 
  the 
  bank 
  since 
  it 
  was 
  

   left 
  exposed 
  by 
  the 
  recession 
  of 
  the 
  cataract. 
  

  

  The 
  most 
  recent 
  and 
  most 
  detailed 
  estimates 
  of 
  the 
  age 
  of 
  the 
  gorge 
  

   have 
  been 
  made 
  by 
  Prof. 
  C. 
  H. 
  Hitchcock.^ 
  He 
  assumes 
  that 
  the 
  

   present 
  rate 
  of 
  recession 
  is 
  four 
  feet 
  annually, 
  and 
  finds 
  accordingly 
  

   that 
  the 
  last 
  formed 
  section 
  of 
  the 
  gorge, 
  from 
  the 
  present 
  falls 
  

   to 
  the 
  point 
  where 
  it 
  suddenly 
  contracts 
  above 
  the 
  railroad 
  

   bridges, 
  was 
  formed 
  during 
  2962 
  years, 
  which 
  closely 
  agrees 
  

   with 
  Pohlman's 
  estimate. 
  Thus 
  the 
  beginning 
  of 
  the 
  great 
  

   cataract 
  at 
  the 
  northern 
  end 
  of 
  the 
  upper 
  great 
  gorge 
  '* 
  dates 
  back 
  

   to 
  1062 
  B.C., 
  300 
  years 
  before 
  the 
  time 
  of 
  Romulus, 
  or 
  

  

  'Pop. 
  sci. 
  monthly. 
  1899. 
  55:145-55- 
  

   ^Am. 
  antiq. 
  Jan. 
  1901. 
  

  

  