﻿THE 
  EPICENTRAL 
  TRACT, 
  155 
  

  

  in 
  

  

  ore 
  defined 
  and 
  the 
  water 
  gradually 
  shallows 
  to 
  the 
  head 
  of 
  the 
  

   pool, 
  where 
  there 
  is 
  an 
  extensive 
  deltaic 
  deposit 
  of 
  sand 
  brought 
  

   down 
  by 
  the 
  stream 
  of 
  the 
  Rongtham. 
  

  

  About 
  3 
  miles 
  above 
  Lenkra 
  the 
  Rongtham 
  divides 
  into 
  two 
  

   branches 
  at 
  the 
  village 
  of 
  Dobu, 
  and 
  in 
  the 
  western 
  of 
  these, 
  just 
  

   above 
  the 
  junction, 
  a 
  pool 
  of 
  about 
  half 
  a 
  mile 
  long 
  and 
  a 
  maximum 
  

   depth 
  of 
  10 
  feet 
  has 
  been 
  formed. 
  

  

  From 
  Dobu 
  I 
  crossed 
  into 
  the 
  drainage 
  area 
  of 
  the 
  Ronghri 
  and 
  at 
  

   Naphak 
  found 
  a 
  group 
  of 
  three 
  lakes, 
  in 
  a 
  series 
  of 
  parallel 
  valleys 
  

   having 
  a 
  general 
  course 
  of 
  about 
  north 
  and 
  south. 
  Of 
  these 
  the 
  

   central 
  and 
  western 
  flow 
  north 
  and 
  unite 
  below 
  the 
  lakes, 
  the 
  

   eastern 
  on 
  the 
  other 
  hand 
  drains 
  to 
  the 
  south 
  and 
  joins 
  the 
  central 
  

   stream 
  above 
  the 
  lake 
  in 
  it. 
  

  

  The 
  easternmost 
  of 
  the 
  three 
  lakes 
  is 
  in 
  the 
  valley 
  of 
  a 
  small 
  

   tributary 
  which 
  apparently 
  carried 
  no 
  water 
  in 
  the 
  dry 
  weather, 
  at 
  

   any 
  rate 
  the 
  water 
  was 
  absolutely 
  stagnant, 
  there 
  being 
  no 
  current 
  

   over 
  the 
  barrier 
  at 
  the 
  outlet. 
  This 
  valley 
  had 
  an 
  alluvial 
  bottom 
  

   which 
  has 
  been 
  flooded 
  for 
  a 
  maximum 
  width 
  of 
  about 
  ioo 
  yards 
  and 
  

   a 
  depth 
  of 
  certainly 
  not 
  more 
  than 
  12 
  feet, 
  a 
  sounding 
  of 
  9! 
  feet 
  

   being 
  obtained 
  at 
  the 
  only 
  place 
  where 
  I 
  could 
  get 
  well 
  out 
  into 
  

   the 
  centre. 
  Owing 
  to 
  the 
  character 
  of 
  the 
  valley 
  there 
  is 
  no 
  clear 
  

   channel 
  through 
  the 
  lake, 
  but 
  the 
  whole 
  width 
  of 
  the 
  water 
  is 
  occu- 
  

   pied 
  by 
  a 
  thicket 
  of 
  dead 
  saplings 
  and 
  bamboos. 
  At 
  the 
  outlet 
  the 
  

   alluvium 
  of 
  the 
  valley 
  is 
  very 
  much 
  fissured. 
  

  

  The 
  central 
  lake 
  is 
  larger 
  and 
  more 
  open, 
  the 
  latter 
  fact 
  being 
  

   largely 
  due 
  to 
  its 
  having 
  been 
  formed 
  in 
  aj'/ium, 
  or 
  forest 
  clearance 
  

   for 
  temporary 
  cultivation. 
  It 
  is 
  about 
  a 
  mile 
  long 
  and 
  about 
  12 
  feet 
  

   maximum 
  depth. 
  The 
  outlet 
  at 
  the 
  lower 
  end 
  is 
  over 
  crystalline 
  

   gneiss, 
  and 
  the 
  water 
  deepens 
  gradually 
  to 
  the 
  lake. 
  

  

  The 
  western 
  lake 
  is 
  rather 
  smaller 
  but 
  of 
  the 
  same 
  type. 
  

  

  The 
  barriers 
  of 
  these 
  two 
  lakes 
  might 
  be 
  ascribed 
  to 
  a 
  single 
  

   roll 
  or 
  fold 
  striking 
  about 
  N\V 
  and 
  crossing 
  both 
  the 
  valleys 
  

   which 
  drain 
  to 
  the 
  northwards. 
  The 
  barriers 
  of 
  the 
  eastern 
  lake 
  

   must, 
  however, 
  be 
  attributed 
  to 
  a 
  different 
  fold, 
  for 
  the 
  valley 
  drains 
  

  

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  155 
  ) 
  

  

  