﻿238 
  eev. 
  j. 
  f. 
  blake 
  on 
  some 
  [May 
  1897, 
  

  

  From 
  the 
  preceding 
  observations 
  we 
  may 
  safely 
  conclude 
  that 
  

  

  (i) 
  This 
  laterite 
  and 
  its 
  associates 
  were 
  formed 
  in 
  water. 
  

  

  (ii) 
  They 
  are 
  not 
  the 
  result 
  of 
  the 
  decomposition 
  of 
  any 
  rock 
  

   in 
  situ. 
  

  

  (iii) 
  They 
  are 
  detrital 
  in 
  origin. 
  

  

  (iv) 
  They 
  were 
  formed 
  at 
  a 
  time 
  when 
  the 
  surface 
  of 
  the 
  country 
  

   was 
  not 
  very 
  different 
  from 
  what 
  it 
  is 
  at 
  the 
  present 
  day, 
  but 
  when 
  

   the 
  water-level 
  was 
  120 
  feet 
  or 
  more 
  higher 
  than 
  now. 
  

  

  As 
  to 
  the 
  source 
  of 
  the 
  detritus, 
  the 
  materials 
  of 
  the 
  sandstones, 
  

   etc., 
  might 
  easily 
  be 
  procured 
  from 
  the 
  higher 
  Jurassic 
  rocks, 
  and 
  

   the 
  iron 
  of 
  the 
  laterite 
  itself 
  could 
  be 
  found 
  abundantly 
  in 
  the 
  

   same 
  beds 
  or 
  in 
  the 
  lower 
  Jurassics 
  — 
  though 
  possibly 
  not 
  in 
  a 
  state 
  

   suited 
  for 
  solution. 
  But 
  we 
  cannot 
  derive 
  the 
  agates 
  thence, 
  and 
  

   agates 
  and 
  iron 
  probably 
  came 
  together. 
  Agates 
  are 
  abundant 
  in 
  

   certain 
  of 
  the 
  lower 
  flows 
  of 
  trap, 
  and 
  to 
  such 
  rocks 
  we 
  must 
  look 
  

   for 
  the 
  source 
  of 
  the 
  laterite. 
  Now, 
  as 
  the 
  ' 
  stratified 
  traps 
  ' 
  are 
  

   flows 
  without 
  pipes, 
  and 
  in 
  the 
  Jurassic 
  area 
  to 
  the 
  north 
  of 
  them 
  

   there 
  are 
  several 
  pipes 
  without 
  flows, 
  it 
  has 
  been 
  natural 
  to 
  connect 
  

   the 
  one 
  with 
  the 
  other 
  ; 
  and 
  if 
  the 
  southern 
  traps 
  were 
  emitted 
  

   from 
  these 
  pipes, 
  there 
  must 
  have 
  been 
  flows 
  also 
  to 
  the 
  north. 
  

   Here, 
  however, 
  is 
  a 
  sharp 
  anticlinal 
  visibly 
  bringing 
  in 
  the 
  higher 
  

   Jurassics, 
  so 
  that 
  the 
  relics 
  of 
  such 
  flows 
  would 
  now 
  be 
  hidden 
  

   beneath 
  the 
  Kan 
  ; 
  and 
  it 
  is 
  from 
  the 
  degradation 
  of 
  these 
  flows 
  that 
  

   we 
  may 
  best 
  seek 
  the 
  source 
  of 
  the 
  laterites. 
  This 
  would 
  account 
  

   for 
  their 
  occurrence 
  on 
  the 
  north 
  side, 
  but 
  not 
  on 
  the 
  south 
  side 
  

   of 
  the 
  inner 
  Ean. 
  

  

  In 
  the 
  absence 
  of 
  any 
  organic 
  remains, 
  it 
  is 
  impossible 
  to 
  say 
  

   whether 
  they 
  are 
  marine 
  or 
  lacustrine 
  deposits. 
  Their 
  resemblance 
  

   to 
  the 
  higher 
  Jurassic 
  rocks 
  which 
  have 
  associated 
  plant-beds 
  

   points 
  to 
  the 
  latter, 
  in 
  which 
  case 
  we 
  may 
  call 
  in 
  the 
  aid 
  of 
  vegeta- 
  

   tion, 
  as 
  suggested 
  by 
  McGee 
  and 
  by 
  Mallet 
  ; 
  but 
  as 
  there 
  are 
  

   other 
  deposits 
  which 
  have 
  a 
  similar 
  distribution, 
  and 
  yet 
  contain 
  

   remains 
  of 
  apparently 
  marine 
  shells, 
  and 
  as 
  moreover 
  a 
  depression 
  is 
  

   easier 
  to 
  imagine 
  than 
  a 
  barrier, 
  the 
  former 
  becomes 
  at 
  least 
  equally 
  

   probable. 
  

  

  (5) 
  The 
  Alluvium 
  and 
  Ran. 
  

  

  The 
  area 
  marked 
  as 
  alluvium 
  on 
  Mr. 
  Wynne's 
  map 
  is 
  a 
  very 
  large 
  

   one. 
  It 
  occupies 
  no 
  less 
  than 
  800 
  square 
  miles. 
  A 
  large 
  portion 
  

   of 
  it, 
  however, 
  lies 
  along 
  the 
  southern 
  margin 
  of 
  the 
  province, 
  

   overlying 
  fossiliferous 
  Tertiary 
  rocks, 
  and 
  it 
  is 
  to 
  this 
  portion 
  that 
  

   I 
  think 
  Mr. 
  Wynne's 
  description 
  must 
  especially 
  apply, 
  when 
  he 
  

   says 
  that 
  ' 
  it 
  is 
  the 
  result 
  of 
  the 
  degradation 
  of 
  the 
  local 
  rocks, 
  

   consisting 
  largely 
  of 
  materials 
  derived 
  from 
  the 
  Tertiary 
  beds, 
  

   frequently 
  mingled 
  with 
  travelled 
  fragments 
  brought 
  by 
  rivers 
  from 
  

   the 
  hills.' 
  On 
  this 
  part 
  of 
  the 
  alluvial 
  area 
  I 
  have 
  nothing 
  to 
  say, 
  

   but 
  of 
  those 
  parts 
  which 
  are 
  in 
  relation 
  to 
  the 
  Jurassic 
  rocks 
  the 
  

   above 
  is 
  scarcely 
  a 
  suitable 
  description. 
  In 
  these 
  I 
  have 
  found 
  

   no 
  evidence 
  that 
  the 
  materials 
  are 
  specially 
  of 
  local 
  origin 
  or 
  of 
  

   Tertiary 
  derivation, 
  and 
  no 
  travelled 
  fragments 
  have 
  been 
  any- 
  

  

  