﻿E. 
  S. 
  Tarr 
  — 
  Arctic 
  Sea 
  Ice 
  as 
  a 
  Geological 
  Agent 
  225 
  

  

  narrow 
  and 
  perfectly 
  protected 
  bays, 
  there 
  were 
  beaches 
  of 
  

   bowlders, 
  averaging 
  a 
  foot 
  or 
  two 
  in 
  diameter, 
  and 
  beneath 
  

   these, 
  forming 
  the 
  bottom 
  of 
  the 
  bay, 
  was 
  mad. 
  No 
  other 
  

   agent 
  than 
  ice 
  could 
  possibly 
  have 
  placed 
  these 
  bowlders 
  in 
  

   this 
  position, 
  and 
  upon 
  the 
  stranded 
  blocks 
  of 
  ice 
  there 
  were 
  

   some 
  bowlders 
  journeying 
  toward 
  the 
  beach. 
  Similar 
  bowlder 
  

   beaches 
  were 
  found 
  in 
  the 
  valleys 
  of 
  the 
  land, 
  showing 
  that 
  

   when 
  the 
  land 
  was 
  formerly 
  lower 
  this 
  same 
  ice 
  action 
  was 
  in 
  

   progress. 
  

  

  There 
  is 
  another 
  way 
  also 
  in 
  which 
  the 
  sea 
  ice 
  aids 
  in 
  the 
  

   work 
  of 
  erosion 
  on 
  the 
  shores. 
  The 
  rocks 
  of 
  the 
  JSTew 
  Eng- 
  

   land 
  coast 
  are 
  covered 
  with 
  a 
  protective 
  mat 
  of 
  seaweed, 
  

   barnacles 
  and 
  other 
  forms 
  of 
  life, 
  while 
  the 
  Arctic 
  shores 
  are 
  

   entirely 
  free 
  from 
  this 
  covering, 
  except 
  in 
  the 
  minute 
  and 
  

   most 
  protected 
  crevices. 
  Because 
  of 
  the 
  ice 
  grinding 
  on 
  

   the 
  shore, 
  life 
  is 
  impossible 
  in 
  the 
  intertidal 
  zone, 
  although 
  at 
  

   a 
  short 
  distance 
  below 
  this, 
  both 
  animal 
  and 
  plant 
  life 
  are 
  extra- 
  

   ordinarily 
  abundant. 
  Lacking 
  the 
  protection 
  of 
  this 
  organic 
  

   mat, 
  the 
  rocks 
  are 
  open 
  to 
  the 
  direct 
  attack 
  of 
  the 
  water, 
  and 
  

   its 
  agents 
  must, 
  therefore, 
  work 
  with 
  greater 
  rapidity, 
  in 
  a 
  

   given 
  period 
  of 
  time, 
  than 
  they 
  do 
  upon 
  a 
  similar 
  coast 
  that 
  is 
  

   protected 
  by 
  organisms. 
  

  

  Erosion 
  by 
  Glacier 
  Ice. 
  — 
  In 
  a 
  less 
  noticeable 
  way 
  the 
  action 
  

   of 
  the 
  glacial 
  ice 
  is 
  the 
  same. 
  It 
  is 
  used 
  in 
  the 
  same 
  manner 
  

   as 
  the 
  sea-made 
  ice, 
  and 
  adds 
  to 
  its 
  efficiency 
  both 
  in 
  protect- 
  

   ing 
  and 
  destroying 
  ; 
  but 
  there 
  are 
  two 
  additional 
  ways 
  in 
  

   which 
  the 
  glacier 
  ice 
  does 
  work 
  of 
  erosion 
  after 
  it 
  leaves 
  the 
  

   glacier. 
  In 
  order 
  to 
  understand 
  the 
  first 
  of 
  these 
  it 
  is 
  neces- 
  

   sary 
  to 
  know 
  how 
  the 
  icebergs 
  are 
  put 
  forth 
  into 
  the 
  sea. 
  So 
  

   far 
  as 
  I 
  could 
  observe, 
  there 
  are 
  several 
  ways 
  in 
  which 
  the 
  

   ice 
  conies 
  from 
  the 
  glacier 
  front. 
  As 
  has 
  been 
  said, 
  some 
  

   pieces, 
  usually 
  of 
  small 
  size, 
  drop 
  because 
  of 
  surface 
  melting, 
  

   and 
  others 
  fall 
  because 
  the 
  sea 
  undermines 
  the 
  ice 
  cliffs. 
  Be- 
  

   sides 
  these 
  sources 
  of 
  glacier 
  ice 
  there 
  is 
  the 
  effect 
  of 
  the 
  water, 
  

   which 
  buoys 
  up 
  the 
  front 
  of 
  the 
  glacier 
  until 
  a 
  breaking 
  

   results, 
  when 
  bergs, 
  usually 
  of 
  large 
  size, 
  proceed 
  from 
  the 
  

   front 
  of 
  the 
  glacier. 
  

  

  In 
  some 
  cases 
  this 
  process 
  of 
  iceberg 
  formation 
  happens 
  very 
  

   quietly, 
  and 
  the 
  front 
  merely 
  cracks 
  off 
  and 
  floats 
  away 
  ; 
  but 
  

   much 
  more 
  commonly 
  the 
  breaking 
  is 
  accompanied 
  by 
  a 
  very 
  

   decided 
  disturbance. 
  The 
  end 
  of 
  the 
  glacier 
  has 
  attained 
  an 
  

   unstable 
  position 
  ; 
  melting 
  or 
  undercutting 
  cracks 
  off 
  a 
  frag- 
  

   ment, 
  and 
  the 
  accompanying 
  jar 
  causes 
  others 
  to 
  follow. 
  The 
  

   air 
  is 
  filled 
  with 
  sounds, 
  as 
  if 
  of 
  musketry, 
  and 
  from 
  the 
  glacier 
  

   front 
  there 
  is 
  a 
  constant 
  shower 
  of 
  small 
  pieces 
  and 
  large 
  

   blocks. 
  Whenever 
  a 
  great 
  mass 
  falls 
  away, 
  numbers 
  of 
  others 
  

   equally 
  large 
  or 
  larger 
  follow 
  very 
  closely. 
  These 
  do 
  not 
  

  

  