﻿32 
  

  

  Section 
  10. 
  — 
  Boundaries. 
  

  

  In 
  describing" 
  the 
  Jabalpur 
  and 
  Bagra 
  groups 
  as 
  they 
  appear 
  along 
  

  

  m 
  , 
  ,, 
  , 
  ", 
  the 
  north 
  edge 
  of 
  the 
  basin, 
  the 
  general 
  charac- 
  

  

  The 
  north 
  boundary 
  : 
  & 
  ' 
  ° 
  

  

  its 
  general 
  features. 
  ^ 
  QVS 
  Q 
  f 
  ^e 
  "b 
  oun 
  daiy 
  have 
  been 
  noticed 
  : 
  how, 
  at 
  

  

  many 
  places 
  and 
  for 
  considerable 
  lengths, 
  conglomeritic 
  sedimentary 
  

   rocks 
  are 
  steeply 
  banked 
  against 
  narrow 
  fringing 
  ridges, 
  or 
  rest 
  upon 
  

   the 
  edges 
  of 
  low 
  reefs, 
  of 
  metamorphics 
  ; 
  both, 
  it 
  is 
  perfectly 
  plain, 
  in 
  

   their 
  original 
  relative 
  positions. 
  The 
  question 
  thus 
  presents 
  itself 
  — 
  are 
  

   these 
  metamorphics 
  the 
  remnants 
  of 
  spurs, 
  or 
  headlands, 
  of 
  a 
  once 
  con- 
  

   tinuous 
  and 
  elevated 
  area 
  of 
  these 
  rocks 
  in 
  the 
  position 
  of 
  the 
  present 
  

   Narbada 
  valley 
  ? 
  or 
  are 
  they 
  only 
  a 
  chain 
  of 
  islands 
  or 
  hills 
  forming, 
  

   indeed, 
  the 
  original 
  general 
  limit 
  of 
  the 
  actual 
  basin 
  of 
  sedimentary 
  

   rocks, 
  but 
  through 
  and 
  beyond 
  which 
  these 
  rocks 
  formerly 
  extended 
  

   indefinitely 
  over 
  the 
  position 
  of 
  the 
  present 
  valley 
  ? 
  

  

  The 
  direct 
  evidence 
  for 
  the 
  discussion 
  of 
  this 
  question 
  is 
  wanting". 
  

  

  _, 
  ., 
  . 
  . 
  . 
  The 
  only 
  rocks 
  that 
  do 
  show 
  under 
  the 
  old 
  alluvial 
  

  

  Possible 
  extension 
  in 
  J 
  

  

  the 
  Narbad& 
  valley. 
  deposits 
  of 
  the 
  valley 
  are 
  metaniorphics 
  ; 
  but 
  there 
  

  

  is 
  a 
  very 
  large 
  area, 
  and 
  precisely 
  in 
  front 
  of 
  the 
  coal-basin, 
  where 
  the 
  

   subjacents 
  have 
  not 
  been 
  observed 
  ; 
  so 
  that 
  we 
  are 
  left 
  to 
  more 
  indirect 
  

   argument. 
  There 
  are 
  some 
  presumptive 
  difficulties 
  that 
  cannot 
  be 
  

   ignored 
  in 
  approaching 
  this 
  question 
  : 
  supposing 
  the 
  present 
  bounding 
  

   ridges 
  to 
  be 
  remnants 
  of 
  a 
  former 
  main-land 
  of 
  metamorphics, 
  how 
  

   to 
  account 
  for 
  the 
  removal 
  of 
  such 
  a 
  prominent 
  mass 
  of 
  the 
  fundamental 
  

   r0 
  ck 
  — 
  the 
  actual 
  reversal 
  of 
  the 
  orographical 
  features 
  — 
  the 
  conversion 
  

   of 
  what 
  must 
  then 
  have 
  been 
  an 
  area 
  of 
  water-shed 
  into 
  what 
  is 
  

   now 
  the 
  main 
  water-way. 
  The 
  analogy 
  of 
  other 
  parts 
  of 
  India 
  adds 
  

   much 
  to 
  the 
  force 
  of 
  this 
  objection 
  ; 
  for 
  it 
  is 
  there 
  very 
  remarkable 
  

   how 
  generally 
  the 
  main 
  actual 
  drainage-depressions 
  correspond 
  with 
  the 
  

   basins 
  of 
  the 
  coal-bearing 
  sedimentaries. 
  From 
  this 
  point 
  of 
  view, 
  

   therefore, 
  it 
  would 
  seem 
  probable, 
  that 
  no 
  mountainous 
  mass 
  of 
  meta- 
  

   morphics 
  occupied 
  the 
  ground 
  to 
  the 
  north 
  of 
  the 
  present 
  boundary 
  

   ( 
  164 
  ) 
  

  

  