﻿RIVER 
  ALLUVIA. 
  

  

  U 
  

  

  When 
  the 
  change 
  in 
  the 
  course 
  of 
  the 
  river 
  took 
  place 
  is 
  not 
  known, 
  

   but 
  from 
  the 
  above 
  fact 
  it 
  probably 
  happened 
  at 
  no 
  very 
  remote 
  period, 
  

   even 
  historically 
  considered. 
  The 
  probable 
  cause 
  of 
  the 
  change, 
  if 
  a 
  

   natural 
  one, 
  was 
  the 
  silting 
  up 
  of 
  the 
  old 
  river 
  valley, 
  which 
  raised 
  the 
  

   river 
  sufficiently 
  during 
  some 
  great 
  flood 
  to 
  find 
  its 
  way 
  through 
  

   and 
  across 
  a 
  dam 
  of 
  gneiss 
  rocks, 
  still 
  in 
  part 
  remaining 
  opposite 
  

   Mavamunglum 
  and 
  Maundoor, 
  when 
  the 
  fall 
  of 
  the 
  land 
  surface 
  being 
  

   more 
  rapid 
  in 
  an 
  easterly 
  direction 
  than 
  in 
  the 
  old 
  bed, 
  the 
  latter 
  

   was 
  permanently 
  abandoned, 
  or 
  only 
  filled 
  during 
  the 
  very 
  highest 
  

   floods, 
  while 
  the 
  main 
  river 
  joined 
  the 
  valley 
  of 
  the 
  Cheear 
  river, 
  which 
  

   it 
  followed 
  to 
  the 
  sea. 
  

  

  Another 
  and 
  in 
  many 
  respects 
  similar 
  change 
  of 
  course 
  has 
  taken 
  

  

  _, 
  , 
  „ 
  „ 
  ,, 
  place 
  in 
  the 
  Naggery 
  river. 
  This 
  river 
  has 
  cut 
  

   Old 
  valley 
  of 
  the 
  l 
  »& 
  J 
  

  

  Naggery 
  river. 
  through 
  a 
  neck 
  of 
  gneissic 
  rock 
  and 
  trap 
  dykes 
  

  

  (about 
  half 
  a 
  mile 
  in 
  width) 
  at 
  a 
  point 
  lying 
  two 
  and 
  half 
  miles 
  east- 
  

   south-east 
  of 
  the 
  town 
  of 
  Naggery, 
  and 
  abandoned 
  the 
  broad 
  alluvial 
  

   valley 
  which 
  stretches 
  eastward 
  along 
  the 
  foot 
  of 
  the 
  Naggery 
  mountain 
  

   towards 
  the 
  Nagloperam 
  range. 
  Before 
  its 
  change 
  of 
  course 
  the 
  Nag- 
  

   gery 
  river 
  undoubtedly 
  joined 
  the 
  Narnaveram 
  river 
  a 
  little 
  to 
  the 
  south 
  

   of 
  Nagloperam 
  village.* 
  

  

  The 
  alluvial 
  valley 
  now 
  occupied 
  by 
  the 
  Conjeveram 
  river 
  or 
  

   The 
  Vaddagar, 
  an 
  old 
  Vadda 
  g 
  ar 
  caa 
  similarly 
  be 
  regarded 
  only 
  as 
  an 
  

   branch 
  of 
  the 
  Palar. 
  abandoned 
  arm 
  of 
  the 
  Palar 
  proper 
  ;— 
  abaudoned, 
  

  

  because 
  silted 
  up. 
  

  

  The 
  alluvium 
  of 
  the 
  Palar 
  is 
  generally 
  nothing 
  but 
  a 
  coarse, 
  gritty, 
  

  

  dusty 
  sand, 
  and 
  rarely 
  consists 
  of 
  gravel; 
  both 
  are 
  

   The 
  Palar 
  alluvium. 
  . 
  , 
  . 
  „ 
  . 
  

  

  made 
  up 
  almost 
  entirely 
  ol 
  the 
  debris 
  of 
  the 
  

  

  coarse-grained 
  granitoid 
  rocks 
  occurring 
  so 
  largely 
  in 
  the 
  North 
  Arcot 
  

  

  * 
  I 
  have 
  heen 
  unable 
  as 
  yet 
  to 
  ascertain 
  whether 
  the 
  natives 
  recognize 
  this 
  alluvial 
  

   valley 
  as 
  an 
  abandoned 
  river 
  course, 
  and 
  have 
  given 
  it 
  any 
  name 
  in 
  reference 
  to 
  that 
  fact 
  as 
  

   in 
  the 
  case 
  of 
  the 
  old 
  Palar. 
  

  

  ( 
  21 
  ) 
  

  

  