﻿78 
  FOOTE 
  : 
  GEOLOGY 
  OF 
  MADRAS. 
  

  

  schist 
  striking 
  north 
  by 
  east, 
  with 
  a 
  dip 
  of 
  75° 
  to 
  85° 
  west 
  by 
  north. 
  

   The 
  schist 
  is 
  much 
  weathered 
  and 
  traversed 
  by 
  a 
  yet 
  more 
  decom- 
  

   posed 
  dyke 
  of 
  trap 
  which 
  has 
  a 
  nearly 
  due 
  east-west 
  course. 
  A 
  very 
  

   few 
  feet 
  above 
  this 
  section 
  occurs 
  probably 
  the 
  junction 
  of 
  the 
  two 
  

   rocks, 
  where 
  there 
  is 
  a 
  slight 
  shelf 
  or 
  terrace 
  on 
  the 
  hill 
  side. 
  

  

  It 
  will 
  be 
  seen 
  on 
  reference 
  to 
  the 
  map 
  that 
  the 
  lowest 
  part 
  of 
  the 
  

   Sattavedu 
  group 
  occurring 
  on 
  the 
  west 
  side 
  of 
  the 
  Sattavedu 
  hills 
  

   rests 
  ou 
  a 
  small 
  outlier 
  of 
  quartzite 
  belonging 
  to 
  the 
  Kaddapa 
  system 
  ; 
  

   whether 
  such 
  an 
  outlier 
  exists 
  under 
  the 
  beds 
  forming 
  the 
  western 
  

   and 
  south-western 
  sides 
  of 
  the 
  Rajmahal 
  area 
  in 
  the 
  Alicoor 
  area 
  is 
  a 
  

   question 
  yet 
  to 
  be 
  decided. 
  The 
  facts 
  which 
  suggest 
  the 
  possibility 
  of 
  

   such 
  outlier 
  of 
  quartzites 
  having 
  been 
  left 
  when 
  

  

  Probable 
  outlier 
  of 
  . 
  , 
  

  

  quartzite 
  of 
  the 
  Kaddapa 
  the 
  great 
  denudation 
  ot 
  the 
  Kaddapa 
  rocks 
  had 
  

  

  taken 
  place 
  previous 
  to 
  the 
  commencement 
  of 
  the 
  

  

  Rajmahal 
  era, 
  are 
  the 
  presence 
  of 
  several 
  groups 
  of 
  huge 
  masses 
  of 
  

  

  quartzite 
  at 
  levels 
  apparently 
  coincident 
  with 
  the 
  junction 
  of 
  the 
  

  

  Rajmahal 
  rocks 
  with 
  the 
  underlying 
  gneissic 
  rocks. 
  These 
  groups 
  of 
  

  

  blocks 
  occur 
  along 
  the 
  southern 
  side 
  of 
  the 
  Naikenpolliam 
  hills 
  ; 
  the 
  

  

  first 
  group 
  occupies 
  a 
  considerable 
  area 
  of 
  ground 
  on 
  the 
  west 
  side 
  

  

  of 
  the 
  rounded 
  hill 
  lying 
  between 
  Illatoor 
  and 
  Naikenpolliam. 
  

  

  The 
  immense 
  number 
  and 
  size 
  of 
  the 
  quartzite 
  blocks 
  lying 
  close 
  

  

  together 
  at 
  this 
  spot, 
  and 
  their 
  angular 
  condition, 
  

   Illatoor 
  bed. 
  

  

  suggest 
  the 
  idea 
  that 
  they 
  are 
  but 
  the 
  ruins 
  of 
  a 
  

   bed 
  of 
  quartzite 
  broken 
  up, 
  but 
  not 
  entirely 
  removed 
  by 
  denudation. 
  

   Several 
  acres 
  of 
  ground 
  are 
  here 
  thickly 
  strewn 
  with 
  these 
  large 
  blocks, 
  

   so 
  thickly, 
  in 
  some 
  parts, 
  that 
  it 
  is 
  easy 
  to 
  walk 
  along 
  the 
  tops 
  of 
  them 
  

   for 
  several 
  yards 
  at 
  a 
  time. 
  Hundreds 
  of 
  these 
  blocks 
  must 
  exceed 
  

   half 
  a 
  ton 
  in 
  weight, 
  and 
  many 
  are 
  yet 
  larger 
  in 
  size. 
  They 
  appear 
  

   to 
  be 
  all 
  of 
  one 
  variety 
  of 
  quartzite, 
  namely, 
  an 
  intensely 
  hard 
  compact 
  

   variety 
  of 
  grey 
  and 
  white 
  colors 
  in 
  bands, 
  and 
  including 
  bands 
  of 
  large 
  

   pebbles 
  of 
  an 
  older 
  quartzite 
  and 
  of 
  jasper. 
  The 
  largest 
  block 
  observed 
  

   ( 
  78 
  ) 
  

  

  