﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  55 
  

  

  Chapter 
  2 
  

  

  LIFE 
  HISTORY 
  OF 
  NIAGARA 
  FALLS 
  

  

  Glacial 
  period 
  

  

  Two 
  important 
  events 
  immediately 
  preceded 
  the 
  birth 
  of 
  Niagara. 
  

   The 
  first 
  was 
  the 
  formation 
  of 
  a 
  series 
  of 
  great 
  lowlands 
  and 
  cuestas 
  

   by 
  stream 
  and 
  atmospheric 
  erosion 
  during 
  a 
  period 
  of 
  time 
  when, 
  

   according 
  to 
  all 
  indications, 
  the 
  land 
  stood 
  from 
  2000 
  to 
  5000 
  feet 
  

   higher 
  than 
  it 
  does 
  now. 
  This 
  was 
  outlined 
  in 
  the 
  preceding 
  chap- 
  

   ter. 
  The 
  second 
  event 
  was 
  the 
  accumulation 
  of 
  a 
  great 
  mantle 
  of 
  

   glacial 
  ice 
  over 
  most 
  of 
  northeastern 
  North 
  America, 
  and 
  the 
  modi- 
  

   fications 
  of 
  the 
  previously 
  formed 
  erosion 
  topography, 
  either 
  by 
  the 
  

   erosive 
  action 
  of 
  the 
  ice 
  or 
  by 
  deposits 
  left 
  on 
  its 
  melting. 
  The 
  

   time 
  equivalent 
  of 
  the 
  latter 
  event 
  is 
  commonly 
  known 
  as 
  the 
  

   glacial 
  period 
  of 
  the 
  earth's 
  history, 
  a 
  remote 
  period 
  as 
  time 
  

   is 
  ordinarily 
  counted, 
  but 
  a 
  very 
  recent 
  one 
  in 
  the 
  chronometry 
  

   of 
  the 
  geologist. 
  Contemporaneous 
  with 
  this 
  great 
  accumulation 
  

   of 
  ice 
  was 
  probably 
  the 
  subsidence 
  of 
  the 
  northern 
  part 
  of 
  this 
  

   region, 
  thus 
  changing 
  the 
  slope 
  of 
  the 
  land 
  surface 
  from 
  a 
  south- 
  

   ward 
  to 
  a 
  northward 
  one. 
  

  

  The 
  greatest 
  accumulation 
  of 
  ice 
  during 
  the 
  glacial 
  period 
  appears 
  

   to 
  have 
  been 
  in 
  the 
  region 
  to 
  the 
  north 
  and 
  northeast 
  of 
  the 
  great 
  

   lakes, 
  or 
  in 
  general 
  over 
  the 
  area 
  of 
  the 
  Laurentian 
  old-land. 
  The 
  

   immediate 
  causes 
  which 
  brought 
  about 
  such 
  accumulation, 
  were 
  the 
  

   extensive 
  refrigeration 
  of 
  the 
  cHmate 
  and 
  the 
  increased 
  precipitation 
  

   of 
  moisture, 
  so 
  that 
  a 
  greater 
  amount 
  of 
  snow 
  fell 
  during 
  the 
  winter 
  

   seasons 
  than 
  could 
  be 
  removed 
  by 
  melting 
  during 
  the 
  succeeding 
  

   summers. 
  The 
  partial 
  melting 
  and 
  refreezing 
  of 
  the 
  snow, 
  which 
  

   continued 
  over 
  a 
  long 
  period 
  of 
  time, 
  eventually 
  resulted 
  in 
  pro- 
  

   ducing 
  glacier 
  ice, 
  after 
  the 
  manner 
  of 
  the 
  formation 
  of 
  glaciers 
  at 
  

   the 
  present 
  time. 
  

  

  The 
  thickness 
  of 
  the 
  great 
  Laurentian 
  glacier, 
  which 
  eventually 
  

   covered 
  all 
  the 
  land 
  of 
  this 
  region, 
  including 
  even 
  the 
  highest 
  moun- 
  

   tains, 
  must 
  be 
  estimated 
  at 
  thousands 
  of 
  feet 
  in 
  its 
  central 
  part 
  with 
  

   a 
  progressive 
  diminution 
  of 
  thickness 
  toward 
  the 
  margin. 
  The 
  ice 
  

  

  