﻿66 
  THEOBALD: 
  GEOLOGY 
  OF 
  PEGU, 
  

  

  but 
  the 
  fine 
  hard 
  sandstone 
  often 
  occupies 
  a 
  high 
  position, 
  whilst 
  a 
  

   coarse 
  conglomerate 
  is 
  not 
  unfrequently 
  met 
  with 
  at 
  its 
  base. 
  Both 
  the 
  

   sandstone 
  and 
  conglomerate 
  are 
  in 
  places 
  richly 
  charged 
  with 
  shark's 
  teeth 
  

   of 
  small 
  size 
  ; 
  and 
  the 
  conglomerate 
  is 
  usually 
  ossiferous 
  as 
  well, 
  though 
  

   the 
  occurrence 
  of 
  mammalian 
  bones 
  is 
  capricious 
  and 
  irregular. 
  I 
  am 
  

   inclined, 
  however, 
  to 
  believe 
  that 
  the 
  scarcity 
  of 
  mammalian 
  bones 
  

   in 
  Pegu, 
  compared 
  with 
  their 
  numbers 
  in 
  Upper 
  Burmah, 
  is 
  to 
  some 
  

   extent, 
  if 
  not 
  mainly, 
  due 
  to 
  the 
  fact 
  of 
  the 
  very 
  imperfect 
  mineralisation 
  

   which 
  many 
  of 
  the 
  bones 
  have 
  undergone 
  in 
  Pegu, 
  and 
  their 
  consequent 
  

   destruction 
  and 
  removal 
  by 
  atmospheric 
  action 
  when 
  weathered 
  out 
  of 
  the 
  

   beds 
  wherein 
  they 
  have 
  been 
  preserved. 
  One 
  locality 
  where 
  I 
  was 
  

   struck 
  by 
  the 
  friable 
  character 
  of 
  the 
  bones 
  which 
  appeared 
  to 
  be 
  far 
  

   from 
  rare 
  in 
  the 
  rock, 
  though 
  scarce 
  on 
  the 
  surface, 
  is 
  a 
  little 
  to 
  the 
  

   North-east 
  of 
  Talok 
  and 
  some 
  fourteen 
  miles 
  North-east 
  of 
  Thayet-mio, 
  

   on 
  the 
  East 
  bank 
  of 
  a 
  small 
  stream 
  not 
  marked 
  in 
  the 
  map. 
  They 
  here 
  

   occur 
  both 
  in 
  the 
  soft 
  upper 
  sand 
  and 
  also 
  in 
  the 
  lower 
  sand 
  and 
  conglome- 
  

   rate, 
  associated 
  with 
  shark's 
  teeth 
  and 
  small 
  pieces 
  of 
  fossil-wood. 
  Many 
  

   of 
  the 
  bones 
  at 
  this 
  locality 
  were 
  of 
  large 
  size, 
  and 
  consisted 
  of 
  jaw 
  and 
  

   limb 
  bones 
  of 
  Elephas, 
  but 
  too 
  friable 
  for 
  removal, 
  and 
  some 
  of 
  which 
  

   had 
  suffered 
  fracture 
  and 
  had 
  been 
  rolled 
  and 
  rounded 
  prior 
  to 
  deposition 
  

   in 
  the 
  sands 
  and 
  gravels. 
  The 
  mammalian 
  bones 
  here 
  were 
  certainly 
  

   associated 
  with 
  shark's 
  teeth 
  ; 
  and 
  therefore 
  I 
  judge 
  that 
  this 
  portion 
  of 
  

   the 
  group 
  must 
  have 
  been 
  deposited 
  under 
  estuary 
  or 
  marine 
  conditions. 
  

   No 
  shark's 
  teeth 
  or 
  any 
  other 
  fossil 
  whatever 
  has 
  been 
  detected 
  by 
  me 
  

   in 
  the 
  uppermost 
  sand, 
  which 
  is 
  the 
  main 
  repository 
  of 
  the 
  silicified 
  

   trunks 
  ; 
  and 
  as 
  these 
  nowhere 
  exhibit 
  marks 
  of 
  the 
  attacks 
  of 
  xylopha- 
  

   gous 
  mollusca 
  (Teredo, 
  Pholas, 
  Gastrochsena), 
  though, 
  as 
  I 
  have 
  shown, 
  

   they 
  were 
  in 
  all 
  probability 
  water-logged 
  from 
  long 
  immersion, 
  prior 
  

   to 
  their 
  entombment 
  and 
  mineralisation, 
  the 
  inference 
  is, 
  I 
  think, 
  legitimate 
  

   that 
  the 
  marine 
  or 
  estuary 
  conditions 
  under 
  which 
  the 
  lower 
  portion 
  of 
  

   this 
  group 
  was 
  deposited, 
  eventually 
  gave 
  place 
  to 
  lacustrine 
  conditions, 
  

   ( 
  «4 
  ) 
  

  

  