﻿154 
  GkoIvOGica-l 
  Survey 
  of 
  L,ouisiana 
  [Sect. 
  

  

  of 
  the 
  river 
  has 
  the 
  shape 
  of 
  a 
  great 
  basin 
  ; 
  the 
  hills 
  forming 
  

   the 
  rim 
  of 
  the 
  basin 
  on 
  three 
  sides, 
  and 
  the 
  elevated 
  river 
  ridge 
  on 
  

   the 
  other. 
  The 
  outlet 
  of 
  such 
  a 
  basin 
  must 
  necessarily 
  be 
  at 
  

   its 
  lower 
  end, 
  just 
  above 
  the 
  place 
  where 
  the 
  river 
  again 
  strikes 
  

   the 
  bordering 
  hills. 
  Such 
  bottom-basins 
  are 
  common 
  in 
  all 
  

   alluvial 
  plains. 
  In 
  Red 
  river 
  valley 
  below 
  Shreveport 
  is 
  the 
  

   basin 
  of 
  Bayou 
  Pierre, 
  extending 
  from 
  Shreveport 
  to 
  Grande 
  

   Ecore 
  and 
  having 
  its 
  outlet 
  just 
  above 
  the 
  lower 
  bluff. 
  Above 
  

   Shreveport 
  is 
  the 
  basin 
  of 
  Poston's 
  bayou 
  having 
  its 
  lower 
  limit 
  

   at 
  Miller's 
  bluffs. 
  In 
  the 
  Mississippi 
  valley, 
  probably 
  the 
  best 
  

   example, 
  is 
  the 
  Yazoo 
  bottom 
  extending 
  from 
  Memphis 
  to 
  

   Vicksburg. 
  

  

  Slope 
  of 
  the 
  river. 
  — 
  Varying 
  as 
  it 
  does 
  in 
  different 
  stages 
  and 
  

   dependent 
  as 
  it 
  is 
  on 
  many 
  factors 
  the 
  slope 
  of 
  the 
  river 
  between 
  

   Shreveport 
  and 
  the 
  State 
  line 
  can 
  hardly 
  be 
  stated 
  exactly. 
  

   Of 
  the 
  three 
  methods 
  of 
  determining 
  the 
  average 
  slope 
  by 
  a 
  

   comparison 
  of 
  high 
  water 
  records, 
  bank 
  levels 
  and 
  by 
  simulta- 
  

   neous 
  observations 
  on 
  the 
  water 
  surface, 
  the 
  first 
  two 
  are 
  to 
  be 
  

   preferred. 
  

  

  The 
  average 
  fall 
  in 
  the 
  banks 
  from 
  Missionary 
  to 
  Shreveport 
  

   is 
  .57 
  feet 
  per 
  mile. 
  The 
  high 
  water 
  slopes* 
  vary 
  from 
  .41 
  in 
  the 
  

   flood 
  of 
  1855 
  to 
  .60 
  in 
  the 
  flood 
  of 
  1879. 
  The 
  slope 
  of 
  the 
  flood 
  

   of 
  1892, 
  .55 
  feet 
  or 
  6)^ 
  inches 
  per 
  mile, 
  probably 
  represents 
  

   about 
  the 
  mean. 
  

  

  Smai.i,er 
  Streams 
  of 
  the 
  VALivEvf 
  

  

  Nearly 
  all 
  the 
  streams 
  formerly 
  leading 
  out 
  of 
  Red 
  river 
  have 
  

   now 
  been 
  closed 
  by 
  levee 
  improvements. 
  Their 
  position 
  is 
  

   however 
  well 
  marked 
  by 
  old 
  channels, 
  now 
  mere 
  rain-water 
  

   drains. 
  The 
  streams 
  in 
  the 
  back-lands, 
  not 
  receiving 
  their 
  usual 
  

   compliment 
  of 
  Red 
  river 
  waters, 
  have 
  shrunk 
  to 
  a 
  mere 
  fraction 
  

   of 
  their 
  former 
  size. 
  The 
  intricate 
  network 
  of 
  bayous 
  and 
  

  

  * 
  Tables 
  of 
  high 
  water 
  marks 
  on 
  Red 
  river. 
  Capt. 
  J. 
  H. 
  Willard. 
  

   Annual 
  Report 
  Chief 
  of 
  Eng., 
  for 
  1893, 
  vol. 
  2. 
  

  

  t 
  The 
  nomenclature 
  of 
  these 
  streams 
  is 
  hopelessly 
  confused. 
  I 
  have 
  

   endeavored, 
  in 
  describing 
  the 
  different 
  bayous 
  to 
  give 
  the 
  names 
  

   which 
  have 
  appeared 
  for 
  these 
  bayous 
  in 
  different 
  works 
  and 
  maps 
  and 
  to 
  

   retain 
  the 
  old 
  name 
  if 
  it 
  is 
  not 
  greatly 
  in 
  variance 
  from 
  the 
  common 
  

   name 
  of 
  to-day. 
  

  

  