﻿PRELIMINARY 
  NOTICE. 
  7 
  

  

  broad 
  stretch 
  of 
  low 
  ridges, 
  preserving 
  a 
  general 
  parallelism 
  to 
  the 
  

   scarps 
  and 
  to 
  the 
  general 
  strike 
  of 
  the 
  formations. 
  This 
  area 
  is 
  drained 
  

   principally 
  by 
  the 
  Sonbudra, 
  a 
  tributary 
  of 
  the 
  Denwa, 
  having 
  its 
  prin- 
  

   cipal 
  sources 
  on 
  the 
  Motur 
  ridge, 
  which 
  has 
  here 
  been 
  separated 
  from 
  

   the 
  crystalline 
  plateau, 
  by 
  the 
  denudation 
  of 
  the 
  upper 
  Tawa, 
  into 
  a 
  

   short 
  independent 
  range, 
  terminating 
  in 
  Kilendeo 
  and 
  Asirgarh 
  hills. 
  

  

  It 
  thus 
  appears 
  that, 
  although 
  the 
  Pachmari 
  peaks 
  are 
  higher 
  by 
  

  

  several 
  hundred 
  feet 
  than 
  the 
  summits 
  of 
  the 
  

   The 
  Motur 
  ridge. 
  

  

  Motur, 
  the 
  latter 
  is 
  the 
  main 
  axis 
  of 
  the 
  drainage, 
  

  

  probably 
  corresponding 
  to 
  an 
  original 
  axis 
  of 
  greatest 
  elevation 
  ; 
  which 
  

  

  axis 
  is 
  altogether 
  within 
  the 
  basin 
  of 
  the 
  sedimentary 
  rocks, 
  at 
  a 
  

  

  distance 
  of 
  from 
  eight 
  to 
  twelve 
  miles 
  from 
  the 
  southern 
  boundary. 
  It 
  

  

  seems 
  to 
  correspond 
  with 
  a 
  broad 
  anticlinal 
  flexure. 
  Both 
  the 
  Denwa 
  

  

  and 
  the 
  Sonbudra, 
  having 
  their 
  most 
  distant 
  sources 
  on 
  the 
  Motur 
  rido-e 
  

  

  pass 
  by 
  deep, 
  narrow, 
  cliffed 
  gorges 
  through 
  the 
  massive 
  sandstones 
  of 
  

  

  the 
  Pachmari 
  range. 
  These 
  gorges 
  must 
  have 
  been 
  deeply 
  graven 
  in 
  the 
  

  

  rocks 
  before 
  the 
  ground 
  attained 
  anything 
  like 
  its 
  present 
  configuration. 
  

  

  The 
  figured 
  section 
  (fig. 
  1) 
  very 
  nearly 
  represents 
  the 
  exact 
  features 
  

   The 
  general 
  cross-sec- 
  on 
  a 
  cross-section 
  through 
  the 
  centre 
  of 
  the 
  basin, 
  

   tion 
  of 
  the 
  basin. 
  passing 
  south-south-east 
  through 
  the 
  plateau 
  of 
  

  

  Pachmari. 
  To 
  make 
  it 
  more 
  typical, 
  some 
  characters 
  at 
  either 
  end 
  are 
  

   taken 
  from 
  a 
  short 
  distance 
  to 
  one 
  side, 
  where 
  the 
  general 
  features 
  hap- 
  

   pen 
  to 
  be 
  better 
  exposed 
  than 
  on 
  that 
  precise 
  line. 
  The 
  exceptional 
  fea- 
  

   tures 
  of 
  the 
  northern 
  boundary 
  will 
  be 
  separately 
  illustrated. 
  The 
  

   several 
  rock-groups 
  are 
  only 
  tentatively 
  designated 
  by 
  letters, 
  pending 
  

   the 
  complete 
  examination 
  of 
  the 
  field, 
  and 
  because 
  the 
  limits 
  of 
  the 
  

   groups 
  are 
  locally 
  very 
  ill-defined, 
  owing 
  to 
  the 
  conformable 
  and 
  transi- 
  

   tional 
  character 
  of 
  the 
  formations. 
  The 
  section 
  presents 
  a 
  descending 
  

   series 
  from 
  north 
  to 
  south 
  ; 
  a 
  flat 
  synclinal 
  is 
  a 
  very 
  general 
  feature 
  

   within 
  three 
  miles 
  of 
  the 
  north 
  boundary, 
  but 
  to 
  the 
  south 
  of 
  this 
  the 
  

   rocks 
  have 
  an 
  almost 
  constant 
  northerly 
  dip. 
  

  

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  ) 
  

  

  