﻿ZQ 
  THEOBALD 
  : 
  GEOLOGY 
  OE 
  PEGU. 
  

  

  formation 
  of 
  its 
  proper 
  channel 
  per 
  se, 
  but 
  on 
  the 
  larger 
  question 
  of 
  

   whether 
  it 
  runs 
  through 
  an 
  area 
  undergoing 
  elevation 
  or 
  depression. 
  A 
  

   river 
  in 
  the 
  former 
  case 
  being 
  an 
  excavating 
  one, 
  in 
  the 
  latter 
  a 
  depositing. 
  

  

  As 
  I 
  have 
  elsewhere 
  stated 
  and 
  argued, 
  and 
  restricting 
  the 
  assertion 
  

   to 
  the 
  lower 
  portion 
  or 
  delta 
  of 
  either 
  river, 
  the 
  Irrawadi 
  gives 
  us 
  an 
  

   example 
  of 
  the 
  former 
  ; 
  the 
  Ganges 
  of 
  the 
  latter. 
  The 
  Irrawadi 
  ploughs 
  

   its 
  way 
  to 
  the 
  sea 
  unhesitatingly 
  and 
  undeviatingly 
  (whence 
  its 
  narrow 
  

   channel, 
  on 
  which 
  I 
  have 
  so 
  much 
  dwelt) 
  through 
  plains 
  of 
  homo- 
  

   genous 
  alluvium, 
  mainly, 
  as 
  I 
  hold, 
  deposited 
  under 
  estuary 
  conditions, 
  

   and 
  identical, 
  in 
  every 
  particular, 
  with 
  the 
  deposit 
  now 
  forming 
  in 
  the 
  

   Gulf 
  of 
  Martaban, 
  of 
  which 
  they 
  are 
  simply 
  the 
  extension, 
  above 
  the 
  

   limits 
  of 
  the 
  sea 
  ; 
  whilst 
  the 
  Ganges 
  hurries 
  to 
  the 
  sea, 
  through 
  a 
  delta, 
  

   composed 
  of 
  its 
  own 
  proper 
  fluviatile 
  deposits 
  as 
  distinguished 
  from 
  the 
  

   homogenous 
  or 
  older 
  alluvium 
  of 
  Bengal, 
  whereon 
  they 
  rest 
  with 
  a 
  

   thickness 
  of 
  60 
  to 
  80 
  feet 
  at 
  Calcutta, 
  and 
  the 
  very 
  existence 
  of 
  

   which 
  in 
  one 
  case 
  and 
  non-existence 
  in 
  the 
  other, 
  sufficiently 
  reveal 
  

   the 
  contrasting 
  conditions 
  of 
  the 
  two 
  areas. 
  But 
  on 
  this 
  I 
  shall 
  

   enlarge 
  in 
  another 
  place. 
  

  

  Hill-ranges. 
  — 
  The 
  main 
  orographical 
  features 
  of 
  Pegu 
  are 
  ex- 
  

   tremely 
  simple, 
  the 
  two 
  main 
  ranges 
  of 
  the 
  Eastern 
  and 
  Western 
  

   Yomah, 
  being 
  two 
  hill 
  systems 
  bounding 
  the 
  valley 
  of 
  the 
  Irrawadi, 
  

   whose 
  simplicity 
  of 
  structure, 
  viewed 
  as 
  a 
  whole, 
  is 
  the 
  result 
  of 
  the 
  

   uniformity 
  of 
  the 
  forces 
  to 
  which 
  their 
  elevation 
  is 
  due 
  ; 
  and 
  this 
  remark 
  

   will 
  probably 
  be 
  found 
  to 
  hold 
  good 
  of 
  the 
  ranges 
  running 
  parallel 
  with 
  

   them 
  to 
  the 
  Eastward, 
  viz., 
  the 
  Poungloung 
  and 
  the 
  Great 
  Salwin 
  

   watershed, 
  which 
  separates 
  the 
  basins 
  of 
  the 
  Salwin 
  and 
  Sittoung. 
  

  

  The 
  minor 
  orographical 
  features, 
  or 
  subordinate 
  hill 
  systems 
  and 
  

   surface 
  arrangement, 
  into 
  which 
  the 
  main 
  range 
  is 
  sub 
  -divided 
  and 
  

   parcelled 
  out, 
  are 
  more 
  varied 
  and 
  complex 
  ; 
  since, 
  being 
  mainly 
  due 
  to 
  

   the 
  abrading 
  powers 
  of 
  rain 
  and 
  rivers, 
  their 
  shape 
  and 
  direction 
  is 
  

   considerably 
  modified 
  by 
  local 
  circumstances, 
  as 
  the 
  character 
  of 
  the 
  

  

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