﻿Vol. 
  53.] 
  SUPERFICIAL 
  DEPOSITS 
  IN 
  CTJTCH. 
  237 
  

  

  the 
  INerbudda 
  valley 
  near 
  Surat, 
  as 
  the 
  only 
  laterites 
  which 
  lie 
  

   below 
  well-defined 
  marine 
  deposits. 
  

  

  That 
  there 
  are 
  lateritic 
  beds 
  below 
  and 
  associated 
  with 
  the 
  

   Nummulitic 
  Series 
  in 
  Cutch 
  admits 
  of 
  no 
  dispute 
  ; 
  but 
  those 
  whose 
  

   age 
  can 
  thus 
  be 
  proved 
  all 
  lie 
  on 
  the 
  south 
  side 
  of 
  the 
  trap-escarp- 
  

   ment 
  and 
  rest 
  immediately 
  on 
  the 
  trap 
  itself, 
  where 
  there 
  can 
  be 
  

   little 
  doubt 
  that 
  the 
  lower 
  red 
  earthy 
  varieties 
  are 
  the 
  products 
  of 
  

   decomposition 
  in 
  situ. 
  It 
  is 
  with 
  an 
  entirely 
  distinct 
  area 
  that 
  I 
  

   am 
  concerned, 
  where 
  the 
  laterite 
  is 
  separated 
  from 
  the 
  trap 
  by 
  miles 
  

   of 
  intervening 
  Jurassic 
  rocks 
  and 
  Ran, 
  and 
  is 
  overlain 
  by 
  nothing 
  

   but 
  alluvium. 
  That 
  these 
  also 
  are 
  sub-jSTummulitic 
  depends 
  on 
  the 
  

   assumption 
  that 
  all 
  the 
  lateritic 
  deposits 
  in 
  a 
  province 
  as 
  large 
  as 
  

   Cutch 
  must 
  necessarily 
  be 
  of 
  the 
  same 
  age 
  — 
  an 
  assumption 
  which 
  

   does 
  not 
  appear 
  to 
  me 
  to 
  be 
  warranted. 
  

  

  The 
  superficial 
  group 
  of 
  laterite 
  is 
  found 
  only 
  on 
  the 
  southern 
  

   and 
  western 
  margins 
  of 
  the 
  Ran 
  islands 
  and 
  along 
  the 
  northern 
  

   border 
  (and 
  eastern 
  also 
  according 
  to 
  Mr. 
  Wynne) 
  of 
  Wagir. 
  In 
  the 
  

   course 
  of 
  this 
  range 
  it 
  is 
  found 
  lying 
  on 
  various 
  members 
  of 
  the 
  

   Jurassic 
  series. 
  In 
  the 
  north 
  of 
  Patcham 
  it 
  lies 
  on 
  the 
  oldest, 
  in 
  

   the 
  north 
  of 
  Wagir 
  on 
  the 
  youngest, 
  and 
  on 
  intervening 
  members 
  

   at 
  other 
  places. 
  

  

  This 
  distribution 
  indicates, 
  I 
  think, 
  a 
  later 
  age 
  than 
  the 
  Nummu- 
  

   litic 
  rocks, 
  for 
  these 
  latter 
  rest 
  upon 
  the 
  decomposition-products 
  of 
  

   the 
  trap, 
  which 
  do 
  not 
  require 
  long 
  to 
  form, 
  and 
  they 
  nowhere 
  

   extend 
  to 
  the 
  Jurassic 
  rocks, 
  as 
  they 
  surely 
  must 
  have 
  done, 
  if 
  

   these 
  had 
  been 
  already 
  denuded 
  to 
  any 
  great 
  extent. 
  Whereas, 
  

   before 
  these 
  laterites 
  were 
  produced, 
  not 
  only 
  must 
  the 
  lowest 
  

   Jurassics 
  have 
  been 
  exposed 
  by 
  denudation, 
  but 
  the 
  general 
  contour 
  

   of 
  the 
  country 
  must 
  have 
  been 
  not 
  far 
  different 
  from 
  what 
  it 
  is 
  at 
  

   present. 
  The 
  only 
  indication 
  of 
  age 
  that 
  I 
  can 
  quote 
  is 
  that 
  they 
  

   underlie 
  the 
  boulder-beds 
  in 
  Patcham. 
  

  

  The 
  laterite 
  here 
  is 
  a 
  sort 
  of 
  gravelly 
  deposit, 
  the 
  pieces 
  being 
  of 
  

   fantastic 
  shapes 
  with 
  a 
  crinkly 
  surface. 
  They 
  are 
  dark 
  red 
  or 
  black 
  

   in 
  colour, 
  and 
  consist 
  of 
  concretionary 
  and 
  stringy 
  ferruginous 
  

   matter, 
  more 
  or 
  less 
  closely 
  sprinkled 
  with 
  sand-grains. 
  The 
  

   several 
  pieces 
  often 
  interosculate 
  into 
  a 
  vacuous 
  spongy 
  mass, 
  in 
  

   which 
  case 
  the 
  rock 
  so 
  closely 
  resembles 
  some 
  of 
  the 
  higher 
  members 
  

   of 
  the 
  Jurassic 
  series 
  as 
  to 
  be 
  undistinguishable 
  in 
  hand-specimens. 
  

   In 
  certain 
  well-defined 
  spots, 
  the 
  surface 
  of 
  the 
  ground 
  is 
  covered 
  

   with 
  small, 
  irregularly-shaped, 
  and 
  obviously 
  detrital 
  agates, 
  some- 
  

   times 
  white 
  and 
  sometimes 
  tinged 
  yellow 
  and 
  red. 
  These 
  ferru- 
  

   ginous 
  beds 
  are 
  frequently 
  seen 
  to 
  overlie 
  well-stratified, 
  soft, 
  white 
  

   sandstones 
  and 
  earthy 
  beds, 
  which 
  are 
  tinged 
  with 
  pink 
  and 
  purple 
  

   by 
  the 
  infiltration 
  from 
  the 
  laterite, 
  as 
  seen 
  by 
  the 
  stalactitic 
  form 
  

   of 
  the 
  coloured 
  parts 
  (see 
  fig. 
  1, 
  p. 
  69 
  of 
  Mr. 
  Wynne's 
  memoir). 
  

  

  Deposits 
  of 
  this 
  kind 
  are 
  mostly 
  found 
  at 
  levels 
  relatively 
  low, 
  

   as 
  compared 
  with 
  the 
  surrounding 
  Jurassics, 
  and 
  they 
  seem 
  to 
  be 
  

   limited 
  to 
  a 
  level 
  lower 
  than 
  about 
  120 
  feet 
  above 
  the 
  Ean. 
  They 
  

   are 
  only 
  found 
  inland 
  at 
  spots 
  which 
  would 
  become 
  lakes 
  if 
  the 
  

   water-level 
  were 
  restored 
  to 
  that 
  height. 
  

  

  