﻿BARREN 
  ISLAND. 
  3 
  

  

  which, 
  especially 
  Ramri 
  and 
  Cheduba, 
  contain 
  mud 
  volcanoes, 
  from 
  

   which 
  violent 
  eruptions, 
  accompanied 
  by 
  outbursts 
  of 
  flame, 
  have 
  

   frequently 
  taken 
  place 
  during 
  the 
  last 
  half 
  century. 
  1 
  Mr. 
  W. 
  T. 
  

   Blaoford 
  has 
  recently 
  dissented 
  from 
  this 
  view 
  on 
  the 
  ground 
  that 
  

   the 
  mud 
  volcanoes 
  have 
  "not 
  the 
  slightest 
  connection 
  with 
  any 
  real 
  

   volcanic 
  action/'' 
  2 
  and 
  has 
  suggested 
  that 
  the 
  continuation 
  of 
  the 
  

   zone 
  in 
  question 
  should 
  be 
  sought 
  in 
  the 
  extinct 
  volcano 
  of 
  Puppa, 
  

   in 
  Upper 
  Burma, 
  and 
  another 
  similar 
  volcano 
  near 
  Momein 
  in 
  Yun- 
  

   nan. 
  In 
  a 
  previous 
  paper, 
  however, 
  I 
  have 
  expressed 
  the 
  opinion 
  that, 
  

   although 
  the 
  mud 
  volcanoes 
  in 
  question 
  are 
  non- 
  volcanic 
  in 
  the 
  sense 
  

   that 
  none 
  of 
  the 
  products 
  of 
  eruption 
  have 
  undergone 
  fusion, 
  and 
  that 
  

   the 
  motive 
  force 
  is 
  mainly 
  gas, 
  not 
  steam, 
  they 
  still 
  are 
  due 
  to 
  volcanic 
  

   heat 
  of 
  a 
  low 
  degree 
  of 
  intensity. 
  The 
  rocks 
  of 
  the 
  Ramri 
  group 
  of 
  

   islands 
  are 
  lignitiferous 
  and 
  petroleum-bearing. 
  Similar 
  rocks 
  occur 
  

   over 
  large 
  areas 
  in 
  Burma 
  and 
  Assam, 
  yet 
  it 
  is 
  only 
  in 
  the 
  Ramri 
  Islands 
  

   that 
  fire-emitting 
  mud 
  volcanoes 
  are 
  known. 
  The 
  explanation 
  of 
  this 
  

   peculiarity 
  that 
  I 
  have 
  suggested 
  is, 
  that 
  the 
  islands 
  being 
  situated 
  

   near 
  the 
  extremity 
  of 
  the 
  Sun 
  da 
  zone 
  of 
  volcanic 
  energy, 
  the 
  subterranean 
  

   heat, 
  although 
  insufficient 
  to 
  fuse 
  the 
  rocks 
  and 
  produce 
  volcanic 
  pheno- 
  

   mena 
  in 
  the 
  ordinary 
  sense 
  of 
  the 
  term, 
  is 
  still 
  sufficient 
  to 
  produce 
  

   destructive 
  distillation 
  of 
  the 
  lignite, 
  resulting 
  in 
  the 
  formation 
  of 
  the 
  

   quantities 
  of 
  inflammable 
  gas 
  which 
  constitutes 
  the 
  motive 
  power 
  of 
  the 
  

   mud 
  volcanoes, 
  and 
  which, 
  on 
  bursting 
  forth, 
  rises 
  in 
  flames, 
  sometimes 
  to 
  

   a 
  height 
  of 
  several 
  hundred 
  feet. 
  3 
  I 
  conceive 
  that 
  the 
  heat 
  attains 
  a 
  

   local 
  maximum 
  in 
  the 
  neighbourhood 
  of 
  Ramri, 
  while 
  it 
  is 
  lower 
  on 
  the 
  

   Arakan 
  coast 
  to 
  the 
  north 
  and 
  south, 
  just 
  as 
  the 
  heat 
  of 
  a 
  far 
  higher 
  

   degree 
  of 
  intensity 
  has 
  attained 
  a 
  local 
  maximum 
  at 
  Narcondam 
  and 
  at 
  

   Barren 
  Island, 
  while 
  between 
  these, 
  and 
  between 
  the 
  latter 
  and 
  Sumatra, 
  

   it 
  has 
  not 
  risen 
  sufficiently 
  high 
  to 
  produce 
  true 
  volcanic 
  phenomena 
  

   (above 
  the 
  sea- 
  level 
  at 
  least). 
  Two 
  (undoubtedly 
  mud) 
  volcanoes 
  are 
  said 
  

  

  1 
  The 
  earlier 
  observers 
  in 
  Ramri 
  and 
  Cheduba 
  mistook 
  the 
  mud 
  volcanoes 
  there 
  for 
  real 
  

   volcanoes, 
  and 
  by 
  their 
  accounts 
  Scrope, 
  Daubeny, 
  and 
  others, 
  were 
  led 
  astray. 
  

  

  2 
  Manual 
  of 
  the 
  Geology 
  of 
  India, 
  part 
  2, 
  pages 
  725, 
  730. 
  

   8 
  Records, 
  G. 
  S. 
  I., 
  Vol. 
  XI, 
  page 
  203. 
  

  

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