﻿NEGRAIS 
  EOCKS. 
  117 
  

  

  The 
  massive 
  beds 
  at 
  the 
  base 
  of 
  this 
  group 
  are 
  everywhere 
  most 
  

   conspicuous 
  and 
  of 
  a 
  peculiar 
  greenish 
  hue 
  very 
  characteristic 
  of 
  this 
  

   rock, 
  which 
  hue, 
  however, 
  in 
  some 
  places 
  towards 
  the 
  North 
  is 
  changed 
  

   into 
  a 
  bluish 
  tinge. 
  The 
  rock 
  is 
  a 
  very 
  fine-grained 
  argillaceous 
  

   sandstone, 
  rather 
  compact, 
  but 
  where 
  exposed 
  to 
  the 
  action 
  of 
  the 
  sea, 
  

   its 
  surface 
  usually 
  presents 
  a 
  honeycombed 
  or 
  cancellated 
  appearance, 
  

   the 
  result 
  of 
  a 
  peculiar 
  mode 
  of 
  weathering, 
  the 
  modus 
  operandi 
  and 
  

   proximate 
  cause 
  of 
  which 
  is 
  somewhat 
  obscure. 
  Subordinate 
  to 
  the 
  

   thick-bedded 
  greenish 
  or 
  cancellated 
  sandstone, 
  as 
  it 
  may 
  be 
  conveni- 
  

   ently 
  termed, 
  occurs 
  an 
  irregular, 
  and 
  almost 
  in 
  places 
  stringy 
  bed 
  of 
  

   conglomerate, 
  a 
  prominent 
  feature 
  connected 
  with 
  which 
  is 
  its 
  great 
  

   irregularity 
  and 
  capricious 
  mode 
  of 
  occurrence. 
  It 
  nowhere 
  forms 
  a 
  

   marked 
  bed, 
  save 
  perhaps 
  near 
  Ywot-pa, 
  but 
  dies 
  out 
  and 
  re- 
  appears 
  

   along 
  a 
  certain 
  horizon 
  as 
  an 
  integral 
  constituent 
  of 
  the 
  cancellated 
  

   sandstone, 
  in 
  places 
  forming 
  a 
  stringy 
  course 
  in 
  it, 
  reduced 
  in 
  places 
  to 
  

   little 
  more 
  than 
  a 
  sprinkling 
  of 
  small 
  pebbles 
  in 
  a 
  sandstone 
  matrix, 
  

   whilst 
  in 
  other 
  places 
  it 
  would 
  seem 
  to 
  expand 
  into 
  a 
  thick 
  mass 
  of 
  

   conglomerate, 
  though 
  such 
  instances 
  are 
  very 
  local 
  and 
  circumscribed 
  

   in 
  extent. 
  

  

  This 
  is 
  the 
  conglomerate, 
  I 
  think, 
  which 
  is 
  so 
  largely 
  developed 
  

   in 
  the 
  hill 
  behind 
  Phoung-do 
  ; 
  if 
  so, 
  it 
  nowhere 
  else 
  attains 
  the 
  same 
  

   importance. 
  To 
  this 
  bed 
  may 
  also 
  be 
  referred 
  the 
  masses 
  of 
  conglo- 
  

   merate 
  seen 
  on 
  the 
  shore 
  opposite 
  Ywot-pa, 
  where 
  they 
  stand 
  quite 
  

   isolated 
  between 
  tidemarks, 
  and 
  are 
  so 
  compact 
  as 
  to 
  have 
  resisted 
  the 
  full 
  

   force 
  of 
  the 
  waves 
  on 
  an 
  exposed 
  coast. 
  

  

  This 
  conglomerate 
  is 
  in 
  places 
  almost 
  a 
  pseudo-breccia, 
  the 
  frag- 
  

   ments 
  composing 
  it 
  being 
  but 
  imperfectly 
  rounded. 
  The 
  included 
  frag- 
  

   ments 
  are 
  all 
  small, 
  rarely 
  half 
  an 
  inch 
  across, 
  and 
  usually 
  much 
  smaller, 
  

   and 
  mainly 
  consist 
  of 
  a 
  comminuted 
  dark 
  blue 
  or 
  cream-colored 
  shale 
  

   highly 
  indurated, 
  the 
  latter 
  variety 
  only 
  effervescing 
  very 
  feebly 
  with 
  

   acid. 
  Quartz 
  fragments 
  are 
  here 
  very 
  subordinate 
  and 
  small. 
  This 
  

  

  ( 
  305 
  ) 
  

  

  