﻿63 
  

  

  Chapter 
  VIII. 
  — 
  Jurassic 
  Rocks. 
  

   The 
  Rajmahal 
  Series. 
  

   The 
  name 
  of 
  the 
  "Rajmahal-" 
  rocks 
  having 
  been 
  given 
  by 
  Dr. 
  

   Oldham 
  and 
  applied 
  by 
  other 
  members 
  of 
  the 
  Geological 
  Survey 
  of 
  India 
  

   to 
  a 
  certain 
  group 
  of 
  beds 
  in 
  the 
  Rajmahal 
  hills 
  in 
  Bengal, 
  it 
  cannot 
  

   be 
  a 
  misnomer 
  to 
  apply 
  the 
  same 
  name 
  to 
  a 
  series 
  of 
  rocks 
  in 
  the 
  Madras 
  

   Presidency, 
  which 
  contain 
  fossils 
  specifically 
  identical 
  with 
  those 
  typical 
  

   of 
  the 
  Bengal 
  rocks. 
  The 
  interest 
  which 
  attaches 
  to 
  these 
  rocks 
  is 
  

   enhanced 
  very 
  greatly 
  by 
  the 
  fact 
  that 
  they 
  have 
  equivalents 
  also 
  in 
  

   Cutch, 
  where 
  their 
  association 
  with 
  beds 
  containing 
  unequivocally 
  Jurassic 
  

   Ammonites 
  and 
  other 
  marine 
  fossils, 
  after 
  having 
  been 
  long 
  suspected 
  in 
  

   consequence 
  of 
  the 
  researches 
  of 
  Colonel 
  Grant,* 
  has 
  been 
  conclusively 
  

   established 
  by 
  the 
  recent 
  labours 
  of 
  Messrs. 
  W. 
  T. 
  Blanford 
  and 
  A. 
  B. 
  

   Wynne 
  of 
  the 
  Geological 
  Survey 
  of 
  India. 
  

  

  The 
  existence 
  of 
  these 
  rocks 
  in 
  the 
  Carnatic 
  as 
  a 
  distinct 
  formation 
  

   was 
  first 
  ascertained 
  in 
  the 
  Trichinopoly 
  district 
  near 
  Ootatoor, 
  where 
  

   fronds 
  of 
  Palaozamice 
  were 
  first 
  discovered 
  by 
  Mr. 
  Charles 
  Oldham. 
  

   Since 
  then 
  they 
  have 
  been 
  traced 
  northward 
  to 
  beyond 
  Nellore 
  occur- 
  

   ring 
  in 
  a 
  number 
  of 
  detached 
  patches, 
  which, 
  except 
  in 
  the 
  neigh- 
  

   bourhood 
  of 
  Madras, 
  are 
  of 
  very 
  small 
  size. 
  

  

  The 
  boundary 
  6f 
  the 
  very 
  irregular 
  area 
  over 
  which 
  these 
  rocks 
  

   extend 
  in 
  the 
  north-east 
  quarter 
  of 
  sheet 
  78 
  of 
  the 
  ' 
  Indian 
  Atlas' 
  stretches 
  

   northward 
  from 
  close 
  to 
  the 
  north 
  bank 
  of 
  the 
  Palar 
  river, 
  about 
  four 
  miles 
  

   west 
  of 
  Conjeveram, 
  to 
  the 
  western 
  extremity 
  of 
  the 
  southern 
  part 
  of 
  the 
  

   Alicoor 
  hills. 
  Thence 
  it 
  follows 
  the 
  westerly 
  base 
  of 
  those 
  hills 
  and 
  of 
  the 
  

   Sattavedu 
  hills. 
  At 
  the 
  northern 
  extremity 
  of 
  the 
  latter 
  group 
  of 
  hills 
  

   the 
  boundary 
  bends, 
  and 
  trends 
  south 
  along 
  their 
  eastern 
  flank 
  down 
  to 
  

  

  * 
  Trans. 
  Geological 
  Society, 
  London, 
  2nd 
  Series, 
  Vol. 
  "V, 
  p. 
  289i 
  Mr. 
  Blanford's 
  

   observations 
  are 
  recorded 
  in 
  the 
  Memoirs 
  of 
  the 
  Geological 
  Survey 
  of 
  India, 
  Vol 
  VI 
  p 
  17 
  

   and 
  Mr. 
  Wynne's 
  in 
  his 
  Report 
  on 
  the 
  Geology 
  of 
  Kutch 
  in 
  Vol. 
  IX 
  of 
  the 
  Memoirs. 
  

  

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  63 
  ) 
  

  

  