﻿36 
  THEOBALD 
  : 
  GEOLOGY 
  OF 
  PEGU, 
  

  

  be 
  no 
  question. 
  Without 
  placing 
  undue 
  reliance 
  on 
  the 
  presumed 
  hut 
  not 
  

   established 
  age 
  of 
  certain 
  masses 
  of 
  limestone 
  at 
  Gwa 
  and 
  Baumi, 
  it 
  

   may 
  be 
  safely 
  assumed 
  from 
  the 
  general 
  arrangement 
  of 
  the 
  Nummulitic 
  

   strata, 
  that 
  at 
  that 
  period 
  the 
  Arakan 
  Range 
  had 
  been 
  hardly 
  more 
  than 
  

   lined 
  out 
  along 
  the 
  bottom 
  of 
  the 
  Eocene 
  ocean 
  ; 
  and 
  if, 
  considering 
  the 
  

   probably 
  joint 
  origin 
  of 
  these 
  twin 
  ranges, 
  we 
  assign 
  the 
  same 
  age 
  to 
  

   both, 
  then 
  the 
  age 
  of 
  the 
  Arakan 
  Range 
  must 
  be 
  still 
  younger, 
  since 
  

   indubitably 
  the 
  Pegu 
  Yomah 
  could 
  hardly 
  have 
  taken 
  shape 
  and 
  form 
  

   before 
  the 
  later 
  Tertiary 
  period, 
  or 
  have 
  experienced 
  its 
  final 
  elevatory 
  

   movements 
  before 
  the 
  post-Pliocene 
  period, 
  if 
  indeed 
  it 
  is 
  safe 
  to 
  infer 
  

   that 
  such 
  have 
  even 
  now 
  ceased, 
  a 
  view 
  I 
  am 
  inclined 
  to 
  question. 
  In- 
  

   dications 
  of 
  elevation 
  during 
  a 
  very 
  recent 
  period 
  are 
  not 
  wanting 
  in 
  

   Arakan, 
  along 
  the 
  coast, 
  in 
  the 
  shape 
  of 
  raised 
  beaches, 
  in 
  the 
  physical 
  

   aspect 
  of 
  the 
  country, 
  and 
  even 
  in 
  native 
  tradition; 
  and 
  though 
  we 
  might 
  

   safely 
  infer 
  a 
  greater 
  amount 
  of 
  elevation 
  along 
  such 
  an 
  axis 
  of 
  eleva- 
  

   tion 
  as 
  the 
  Arakan 
  Range, 
  the 
  opposite 
  supposition 
  that 
  a 
  rise 
  of 
  the 
  

   coast 
  was 
  confined 
  to 
  it, 
  and 
  not 
  participated 
  in 
  by 
  the 
  mountains 
  behind 
  

   it, 
  would 
  be, 
  prima 
  facie, 
  highly 
  untenable 
  and 
  require 
  strong 
  evidence 
  

   in 
  its 
  support. 
  

  

  Towards 
  the 
  frontier 
  the 
  central 
  mass 
  of 
  the 
  Arakan 
  Range 
  is 
  

   composed 
  of 
  a 
  well-marked 
  group 
  of 
  beds, 
  to 
  be 
  noticed 
  as 
  Axials. 
  

   They 
  are 
  of 
  Triassic 
  age, 
  to 
  judge 
  by 
  the 
  sole 
  recognisible 
  fossil 
  they 
  

   have 
  afforded, 
  the 
  Halobia 
  Lommeli 
  Wissm, 
  a 
  species 
  also 
  found 
  in 
  

   the 
  Triassic 
  rocks 
  of 
  the 
  North-Western 
  Himalaya, 
  the 
  " 
  Lilang 
  series" 
  

   (vide 
  Memoirs, 
  Geological 
  Survey 
  of 
  India, 
  Vol. 
  V, 
  page 
  50). 
  The 
  

   relation 
  of 
  these 
  Triassic 
  beds 
  to 
  the 
  younger 
  groups 
  is 
  not 
  so 
  clearly 
  

   made 
  out 
  as 
  is 
  desirable, 
  and 
  their 
  boundary 
  on 
  the 
  Western 
  or 
  Arakan 
  

   side 
  of 
  the 
  range 
  is 
  altogether 
  unexplored. 
  On 
  the 
  Western 
  side 
  of 
  

   the 
  range, 
  it 
  is, 
  however, 
  certain, 
  from 
  a 
  cursory 
  examination 
  along 
  

   the 
  outer 
  ranges, 
  that 
  a 
  very 
  great 
  thickness 
  of 
  beds 
  of 
  Cretaceous 
  

   age 
  intervenes 
  between 
  the 
  Axial 
  group 
  and 
  the 
  Eocene 
  Tertiaries, 
  and 
  

  

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