﻿Nichols: 
  The 
  vegetation 
  of 
  Connecticut 
  547 
  

  

  I 
  

  

  salt 
  marsh 
  grass, 
  instead 
  of 
  forming 
  a 
  zone 
  of 
  vegetation 
  directly 
  

   continuous 
  with 
  that 
  at 
  higher 
  levels 
  along 
  the 
  shore, 
  frequently 
  

   grows 
  in 
  a 
  more 
  or 
  less 
  continuous 
  belt 
  at 
  some 
  little 
  distance 
  

   offshore, 
  being 
  separated 
  from 
  the 
  higher 
  portions 
  of 
  the 
  shore 
  by 
  

   an 
  area, 
  of 
  variable 
  width 
  but 
  sometimes 
  as 
  much 
  as 
  a 
  dozen 
  yards 
  

   across, 
  or 
  even 
  more, 
  in 
  which 
  the 
  ground 
  is 
  practically 
  destitute 
  

   of 
  seed 
  plants 
  (this 
  condition 
  is 
  suggested 
  in 
  FiG. 
  2).* 
  As 
  the 
  

   portion 
  of 
  the 
  shore 
  occupied 
  by 
  the 
  grass 
  becomes 
  built 
  upward, 
  

   this 
  plantless 
  portion 
  lags 
  behind, 
  eventually 
  giving 
  rise 
  to 
  a 
  

   water-filled 
  depression 
  in 
  the 
  mature 
  marsh. 
  In 
  one 
  of 
  the 
  Cape 
  

   Breton 
  salt 
  marshes 
  studied 
  by 
  the 
  writer 
  (see 
  Nichols, 
  ^17, 
  

   Fig. 
  45; 
  also 
  Harvey, 
  '19, 
  Fig. 
  3) 
  these 
  depressions 
  have 
  persisted 
  

   in 
  the 
  mature 
  marsh 
  as 
  elongated 
  lagoons 
  of 
  open 
  water. 
  But 
  

   more 
  commonly 
  they 
  become 
  broken 
  up 
  and 
  in 
  part 
  obliterated, 
  

   during 
  the 
  growth 
  of 
  the 
  marsh, 
  through 
  local 
  invasions 
  of 
  the 
  

  

  + 
  

  

  salt 
  reed 
  grass: 
  indeed, 
  small 
  areas 
  commonly 
  become 
  hemmed 
  in 
  

   by 
  the 
  salt 
  reed 
  grass 
  at 
  a 
  very 
  early 
  stage 
  in 
  the 
  development 
  of 
  

   the 
  pan. 
  Secojidary 
  pans 
  may 
  arise 
  in 
  several 
  ways, 
  one 
  of 
  which 
  

   has 
  already 
  been 
  described. 
  In 
  many 
  cases 
  (Fig. 
  7) 
  their 
  forma- 
  

   tion 
  results 
  from 
  the 
  relatively 
  rapid 
  building 
  up 
  of 
  the 
  ground 
  

   along 
  the 
  margins 
  of 
  tidal 
  streams, 
  with 
  the 
  consequent 
  ponding 
  

   back 
  of 
  the 
  water, 
  between 
  tides, 
  in 
  the 
  lower 
  parts 
  of 
  the 
  meadow, 
  

   away 
  from 
  the 
  stream 
  (see, 
  in 
  this 
  connection, 
  Nichols, 
  '15, 
  

   pp. 
  171, 
  172; 
  also 
  p. 
  537 
  of 
  the 
  present 
  paper). 
  Very 
  commonly, 
  

   also, 
  they 
  arise 
  through 
  the 
  local 
  invasion 
  and 
  obstruction 
  of 
  shal- 
  

   low 
  tidal 
  creeks 
  by 
  the 
  salt 
  marsh 
  grass, 
  a 
  method 
  of 
  development 
  

   graphically 
  brought 
  out 
  by 
  Fig. 
  10. 
  Occasionally 
  they 
  seem 
  to 
  

   originate 
  as 
  ox-bows, 
  in 
  the 
  usual 
  manner, 
  from 
  meandering 
  

   tidal 
  creeks. 
  

  

  The 
  fate 
  of 
  these 
  pans 
  need 
  not 
  be 
  traced 
  in 
  detail. 
  Unchang- 
  

   ing 
  though 
  it 
  may 
  appear, 
  the 
  surface 
  of 
  a 
  salt 
  marsh, 
  from 
  year 
  

   to 
  year, 
  is 
  in 
  a 
  constant 
  state 
  of 
  alteration. 
  Erosion 
  here 
  and 
  

   deposition 
  or 
  peat 
  accumulation 
  there 
  tend 
  to 
  bring 
  about 
  

   changes 
  in 
  drainage 
  and 
  elevation 
  which 
  in 
  turn 
  react 
  on 
  the 
  

   v^egetation. 
  In 
  the 
  shifting 
  course 
  of 
  events 
  the 
  pans 
  of 
  today 
  are 
  

   destined, 
  sooner 
  or 
  later, 
  to 
  vanish, 
  while 
  other 
  areas, 
  now 
  occupied 
  

  

  " 
  " 
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  - 
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  l-L 
  

  

  * 
  The 
  absence 
  of 
  plants 
  here 
  is 
  commonly 
  due 
  to 
  the 
  periodic 
  accumulation 
  alon^ 
  

   the 
  shore 
  of 
  wave-washed 
  drift, 
  after 
  the 
  manner 
  already 
  described 
  (pp. 
  545. 
  546). 
  

  

  