﻿GEOLOGICAL 
  STRUCTURE 
  OP 
  THE 
  5IEKRAN 
  COAST. 
  51 
  

  

  terrace 
  of 
  shelly 
  beds 
  lies, 
  is 
  bored 
  by 
  the 
  living 
  Lithodomus 
  allied 
  

   to 
  the 
  Indo-Pacific 
  L. 
  attenuatus. 
  They 
  appear 
  to 
  be 
  vastly 
  abun- 
  

   dant 
  in 
  the 
  clay, 
  which 
  is 
  riddled 
  by 
  the 
  perforations 
  in 
  all 
  directions 
  

   and 
  at 
  all 
  angles. 
  

  

  " 
  The 
  genera 
  of 
  shells 
  occurring 
  in 
  the 
  shelly 
  layer, 
  believed 
  to 
  

   be 
  of 
  Miocene 
  age, 
  are 
  Eburna, 
  Ostrea, 
  Cyprcea, 
  Co 
  nits, 
  and 
  Cardium 
  ; 
  

   and 
  all 
  occur 
  in 
  the 
  form 
  of 
  casts." 
  

  

  The 
  surface 
  of 
  these 
  beds 
  is 
  in 
  some 
  places 
  strewed 
  with 
  pebbles, 
  

   much 
  water-worn, 
  composed 
  of 
  jasper 
  and 
  quartz, 
  &c, 
  and 
  possibly 
  

   of 
  trappean 
  origin. 
  

  

  With 
  the 
  possible 
  exception 
  of 
  the 
  craters 
  to 
  be 
  shortly 
  referred 
  

   to, 
  the 
  writer 
  has 
  observed 
  no 
  traces 
  of 
  volcanic 
  action 
  on 
  this 
  coast. 
  

   Within 
  the 
  Persian 
  Gulf, 
  however, 
  a 
  similar 
  formation, 
  which 
  ex- 
  

   tends 
  along 
  the 
  entire 
  north 
  coast, 
  and 
  forms 
  all 
  the 
  large 
  islands, 
  has 
  

   been 
  much 
  disturbed 
  by 
  the 
  protrusion 
  of 
  recent 
  volcanie 
  matter. 
  

  

  Near 
  Jashak, 
  at 
  the 
  western 
  end 
  of 
  the 
  coast, 
  is 
  found 
  a 
  hot 
  spring, 
  

   of 
  a 
  temperature 
  of 
  128°, 
  situated 
  near 
  high-water 
  mark, 
  and 
  but 
  

   little 
  above 
  the 
  sea-level. 
  It 
  is 
  unimportant 
  in 
  volume, 
  and 
  has 
  

   six 
  or 
  seven 
  little 
  surface-basins 
  close 
  together. 
  The 
  water 
  emits 
  

   a 
  strong 
  odour 
  of 
  sulphur, 
  and 
  forms 
  a 
  stalagmitic 
  deposit 
  round 
  its 
  

   margin*. 
  There 
  are 
  also 
  springs 
  of 
  pure 
  hot 
  water 
  near 
  Karachi 
  

   beyond 
  the 
  eastern 
  boundary 
  of 
  the 
  region. 
  

  

  As 
  might 
  be 
  expected 
  from 
  the 
  nature 
  of 
  the 
  formation, 
  a 
  vast 
  

   amount 
  of 
  denudation 
  has 
  taken 
  place, 
  and 
  is 
  still 
  in 
  progress, 
  which 
  

   would 
  be 
  much 
  accelerated 
  but 
  for 
  the 
  almost 
  rainless 
  nature 
  of 
  the 
  

   country. 
  The 
  clay 
  being 
  gradually 
  removed 
  by 
  rain, 
  when 
  it 
  occurs, 
  

   or 
  in 
  the 
  sea-cliffs 
  by 
  the 
  action 
  of 
  the 
  waves, 
  the 
  upper 
  stratum 
  

   falls 
  in 
  great 
  masses 
  or 
  slabs, 
  and 
  forms 
  a 
  talus, 
  which 
  in 
  some 
  

   degree 
  protects 
  the 
  base 
  of 
  the 
  cliffs 
  from 
  further 
  disintegration. 
  

  

  On 
  the 
  inland 
  faces 
  of 
  the 
  hills, 
  ravines 
  and 
  precipitous 
  valleys 
  

   are 
  formed 
  in 
  the 
  same 
  manner 
  ; 
  and 
  the 
  surface-crust 
  of 
  the 
  ground, 
  

   cracked 
  and 
  broken 
  in 
  every 
  direction, 
  often 
  presents 
  an 
  appearance 
  

   such 
  as 
  might 
  be 
  the 
  result 
  of 
  an 
  earthquake. 
  

  

  A 
  typical 
  section 
  at 
  Guadur 
  is 
  given 
  in 
  the 
  diagram 
  (fig. 
  2) 
  : 
  the 
  

   immense 
  space 
  between 
  the 
  cliffs 
  has, 
  it 
  is 
  presumed, 
  been 
  removed 
  

   by 
  denudation. 
  The 
  several 
  projecting 
  headlands, 
  and 
  the 
  island 
  

   of 
  Astola, 
  apparently 
  all 
  belong 
  to 
  the 
  same 
  group, 
  and 
  stand 
  as 
  

   remnants 
  showing 
  the 
  original 
  extent 
  of 
  the 
  formation. 
  

  

  In 
  some 
  parts, 
  as 
  at 
  the 
  great 
  headland 
  called 
  the 
  Malan, 
  large 
  

   masses 
  of 
  the 
  clay 
  are 
  constantly 
  falling 
  with 
  a 
  dull 
  roar, 
  breaking 
  

   up 
  into 
  clouds 
  of 
  dust. 
  Prom 
  one 
  cliff 
  the 
  writer 
  has 
  watched 
  a 
  

   succession 
  of 
  such 
  landslips 
  for 
  an 
  hour 
  with 
  hardly 
  any 
  inter- 
  

   mission. 
  

  

  The 
  mud-craters, 
  which 
  have 
  hitherto 
  been 
  attributed 
  to 
  volcanic 
  

   action, 
  are, 
  it 
  is 
  believed, 
  peculiar 
  to 
  this 
  coast. 
  They 
  are 
  found 
  

   over 
  an 
  extent 
  of 
  about 
  200 
  miles 
  of 
  coast 
  from 
  Guadur 
  to 
  Eas 
  

   Kucheri. 
  Probably 
  the 
  most 
  characteristic 
  group 
  is 
  that 
  near 
  the 
  

   latter 
  place, 
  where 
  there 
  are 
  a 
  number 
  close 
  together, 
  some 
  of 
  which 
  

   may 
  be 
  termed 
  extinct, 
  others 
  being 
  in 
  action. 
  These 
  craters 
  vary 
  

   * 
  It 
  is 
  regretted 
  that 
  the 
  specimen 
  for 
  analysis 
  lias 
  been 
  mislaid. 
  

  

  e2 
  

  

  