﻿112 
  F00TE 
  : 
  GEOLOGY 
  OF 
  MADRAS. 
  

  

  The 
  clays 
  exhibit 
  a 
  slight 
  tendency 
  to 
  the 
  cone-in-cone 
  structure 
  

   noticed 
  as 
  occurring 
  at 
  Atrampakkam. 
  

  

  Returning 
  north-westward 
  to 
  Serupanjeri, 
  the 
  surface 
  of 
  the 
  

   rocks, 
  where 
  exposed 
  in 
  the 
  road, 
  shows 
  yellowish 
  friable 
  sandstone, 
  and 
  

   tesselated 
  iron-stone 
  concretions. 
  True 
  laterite 
  and 
  lateritic 
  gravel 
  is 
  

   sparingly 
  scattered 
  over 
  the 
  country, 
  and 
  not 
  unfrequently 
  rounded 
  

   pieces 
  of 
  the 
  tesselated 
  iron-stone 
  occur 
  washed 
  up 
  with 
  it. 
  

  

  A 
  few 
  score 
  yards 
  south-east 
  of 
  Vanjeri, 
  a 
  small 
  elliptical 
  space 
  of 
  

  

  ground, 
  about 
  an 
  acre 
  in 
  extent, 
  is 
  occupied 
  by 
  

   Vanjeri 
  conglomerate. 
  

  

  large, 
  angular, 
  weathered 
  blocks 
  of 
  a 
  very 
  coarse, 
  

  

  hard 
  conglomerate 
  of 
  quartzite 
  pebbles, 
  imbedded 
  in 
  a 
  calcareo-silicious 
  

   cement 
  of 
  pale 
  grey 
  color. 
  This 
  conglomerate 
  stands 
  on 
  the 
  yellowish 
  

   sandy 
  clays 
  before 
  described 
  as 
  occupying 
  the 
  water-shed 
  running 
  north 
  

   of 
  the 
  old 
  road. 
  The 
  blocks 
  which 
  had 
  not 
  been 
  quarried 
  for 
  building 
  

   stones 
  present 
  every 
  appearance 
  of 
  being 
  part 
  of 
  a 
  true 
  stratum, 
  

   the 
  separation 
  into 
  loose 
  blocks 
  being 
  only 
  an 
  effect 
  of 
  weathering. 
  

   A 
  stalactitic 
  incrustation 
  was 
  observed 
  on 
  a 
  few 
  blocks, 
  having 
  at 
  

   first 
  sight 
  considerable 
  similarity 
  to 
  the 
  exterior 
  rugose 
  surface 
  of 
  cup 
  

   corals, 
  but 
  when 
  fractured 
  no 
  cellular 
  structure 
  of 
  any 
  kind 
  was 
  trace- 
  

   able. 
  This 
  conglomerate 
  is 
  so 
  strikingly 
  different 
  from 
  any 
  other 
  for- 
  

   mation 
  in 
  the 
  Sripermatoor 
  basin 
  that 
  I 
  am 
  acquainted 
  with, 
  and 
  is, 
  

   so 
  far 
  as 
  I 
  know, 
  so 
  entirely 
  limited 
  to 
  this 
  small 
  spot, 
  that 
  it 
  becomes 
  

   very 
  difficult 
  to 
  decide 
  to 
  what 
  series 
  of 
  formations 
  to 
  assign 
  it, 
  and 
  

   whether 
  to 
  consider 
  it 
  as 
  a 
  member 
  of 
  the 
  Rajmahal 
  series, 
  or 
  to 
  regard 
  

   it 
  as 
  a 
  solitary 
  and 
  fragmentary 
  remnant 
  of 
  some 
  younger 
  system 
  of 
  

   formations. 
  In 
  the 
  absence 
  of 
  fossils 
  it 
  is 
  hard 
  to 
  decide. 
  The 
  mineral 
  

   character 
  most 
  resembles 
  the 
  Sattavedu 
  conglomerate 
  as 
  seen 
  im- 
  

   mediately 
  west 
  of 
  Sirgulpilly, 
  and 
  it 
  would 
  be 
  rash 
  to 
  separate 
  this 
  

   Vanjeri 
  conglomerate 
  from 
  the 
  Rajmahal 
  series, 
  no 
  non-conformity 
  

   having 
  been 
  proved 
  to 
  exist 
  between 
  it 
  and 
  the 
  underlying 
  clays. 
  

   ( 
  L12 
  ) 
  

  

  