﻿OLDER 
  ALLUVIUM. 
  4>V 
  

  

  deposit 
  like 
  the 
  older 
  alluvial 
  clay, 
  without 
  necessitating 
  the 
  supposi- 
  

   tion 
  of 
  estuary 
  conditions 
  ? 
  Stated 
  thus, 
  it 
  can 
  be 
  only 
  answered 
  by 
  a 
  

   balance 
  of 
  probabilities, 
  for 
  the 
  supposition 
  involves 
  conditions 
  of 
  which 
  

   we 
  have 
  no 
  certain 
  knowledge 
  to 
  guide 
  us. 
  The 
  condition 
  and 
  mode 
  of 
  

   arrangement 
  of 
  modern 
  river 
  deposits 
  may 
  be 
  familiar 
  to 
  us, 
  but 
  this 
  

   does 
  not 
  enable 
  us 
  to 
  solve 
  a 
  purely 
  supposititious 
  ease. 
  What 
  evidence 
  

   there 
  is 
  from 
  analogy 
  with 
  the 
  present 
  Irrawadi, 
  would 
  rather 
  seem 
  to 
  be 
  

   adverse 
  to 
  the 
  idea 
  of 
  any 
  such 
  gradual 
  increments 
  taking 
  place 
  without 
  

   leaving 
  some 
  mark 
  or 
  other 
  behind 
  them-. 
  

  

  Local 
  causes 
  operate 
  to 
  place 
  the 
  Irrawadi 
  during 
  flood, 
  very 
  much 
  

   in 
  the 
  position 
  of 
  a 
  river 
  which 
  shall 
  deposit 
  the 
  least 
  possible 
  amount 
  

   of 
  sediment 
  over 
  the 
  area 
  inundated 
  by 
  it, 
  and 
  this 
  happens 
  from 
  the 
  

   following 
  reason. 
  The 
  delta 
  of 
  the 
  Irrawadi 
  is 
  not 
  only 
  intersected 
  by 
  

   the 
  river, 
  whose 
  flood 
  waters 
  spread 
  over 
  the 
  country 
  within 
  the 
  ordinary 
  

   limits 
  of 
  inundation, 
  but 
  is 
  bounded 
  by 
  hills, 
  which 
  gives 
  rise 
  during 
  the 
  

   monsoon 
  to 
  a 
  number 
  of 
  streams 
  of 
  considerable 
  magnitude, 
  all 
  discharge 
  

   ing 
  into 
  the 
  river. 
  By 
  a 
  well-understood 
  law 
  of 
  all 
  rivers 
  overflowing 
  

   their 
  banks, 
  the 
  land 
  in 
  the 
  immediate 
  vicinity 
  of 
  the 
  main 
  channels 
  

   is 
  higher 
  than 
  that 
  more 
  remote 
  ; 
  hence 
  it 
  happens 
  that 
  by 
  the 
  time 
  

   the 
  flood 
  waters 
  of 
  the 
  Irrawadi 
  have 
  overtopped 
  the 
  banks, 
  the 
  land 
  

   between 
  the 
  banks 
  and 
  the 
  hills 
  skirting 
  the 
  delta 
  has 
  been 
  to 
  some 
  

   extent 
  submerged, 
  partly, 
  from 
  rain 
  water, 
  and 
  partly 
  from 
  the 
  flooded 
  

   streams 
  which 
  have 
  been 
  ponded 
  back 
  by 
  the 
  rising 
  of 
  the 
  main 
  river. 
  

   Most 
  of 
  the 
  coarse 
  sediment 
  brought 
  down 
  by 
  these 
  streams 
  is 
  deposited 
  

   as 
  a 
  sandy 
  talus 
  along 
  the 
  edge 
  of 
  the 
  hills, 
  whilst 
  the 
  water, 
  depurated 
  

   of 
  sediment 
  overflows 
  the 
  country, 
  and 
  on 
  the 
  rising 
  of 
  the 
  river 
  to 
  its 
  

   full 
  height, 
  opposes 
  a 
  perfect 
  barrier 
  to 
  the 
  spread 
  of 
  the 
  river 
  water 
  

   charged 
  with 
  sediment, 
  over 
  the 
  low-lying 
  part 
  of 
  the 
  country, 
  which 
  

   would 
  be 
  most 
  benefitted 
  by 
  its 
  deposition. 
  Of 
  course 
  under 
  surface 
  

   conditions 
  such 
  as 
  I 
  have 
  described, 
  large 
  tracts 
  of 
  country 
  remain 
  

   in 
  the 
  condition 
  of 
  j 
  heels 
  or 
  swamps 
  for 
  half 
  the 
  year, 
  and 
  their 
  

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