﻿322 
  Geological 
  Survey 
  of 
  Louisiana 
  [Sect. 
  

  

  Azimuth, 
  P. 
  R. 
  P. 
  to 
  P. 
  A. 
  P. 
  232° 
  52' 
  47". 
  

  

  Alexandria 
  base 
  line, 
  tertiary 
  triangulation 
  of 
  Red 
  river, 
  is 
  in 
  

   Rapides 
  Parish, 
  La., 
  on 
  the 
  right 
  bank 
  of 
  Red 
  river 
  and 
  behind 
  

   the 
  town 
  of 
  Alexandria. 
  Both 
  ends 
  of 
  the 
  base 
  are 
  marked 
  alike 
  

   with 
  stone 
  and 
  pipe 
  similar 
  to 
  the 
  Shreveport 
  base 
  line. 
  

  

  ' 
  ' 
  Northeast 
  base 
  is 
  in 
  a 
  meadow 
  about 
  50 
  meters 
  southeast 
  of 
  a 
  

   barn. 
  

  

  ' 
  ' 
  Southzvest 
  base 
  is 
  in 
  open 
  field 
  on 
  a 
  low 
  levee 
  about 
  50 
  meters 
  

   east 
  of 
  fence. 
  

  

  Length 
  of 
  Base, 
  955.676 
  meters. 
  

  

  Azimuth, 
  N. 
  E. 
  B., 
  to 
  S. 
  W. 
  B., 
  81° 
  48'. 
  

  

  Latitude, 
  N. 
  E. 
  B., 
  31° 
  17' 
  47". 
  

  

  Elevation 
  top 
  of 
  cap 
  N. 
  E. 
  B., 
  30.21 
  meters, 
  [Cairo 
  Datum.] 
  

  

  Elevation 
  top 
  of 
  cap 
  S. 
  W. 
  B., 
  31.58 
  meters, 
  [Cairo 
  Datum.] 
  

  

  '' 
  Perjuanent 
  reference 
  line 
  , 
  Floyd, 
  Bayou 
  Macon 
  survey, 
  is 
  in 
  

   West 
  Carroll 
  Parish, 
  La., 
  on 
  the 
  right 
  bank 
  of 
  the 
  Bayou 
  in 
  and 
  

   below 
  the 
  town 
  of 
  Floyd. 
  

  

  " 
  Pe7^via7ie7it 
  reference 
  poiiit'xs 
  marked 
  hy 
  a 
  4 
  centimeter 
  gas 
  pipe 
  

   with 
  a 
  sleeve 
  on 
  the 
  upper 
  end, 
  driven 
  in 
  the 
  ground 
  about 
  400 
  

   meters 
  below 
  Floyd 
  on 
  Mrs. 
  Emma 
  White's 
  place. 
  It 
  is 
  about 
  

   150 
  meters 
  west 
  of 
  bayou 
  bank, 
  about 
  10 
  meters 
  west 
  of 
  edge 
  of 
  

   hills, 
  about 
  200 
  meters 
  southeast 
  of 
  dwelling, 
  44 
  meters 
  south 
  of 
  

   cabin 
  and 
  27 
  meters 
  north 
  of 
  fence. 
  

  

  ''Permanent 
  azimuth 
  point 
  is 
  the 
  cupola 
  of 
  the 
  Court 
  House 
  in 
  

   Floyd. 
  

  

  Azimuth, 
  P. 
  R. 
  P. 
  to 
  P. 
  A. 
  P., 
  161° 
  46'. 
  

  

  MAGNETIC 
  DECLINATION 
  

  

  Amount 
  of 
  ' 
  ' 
  variation'" 
  determ,ined 
  by 
  o?ie 
  compass 
  not 
  applicable 
  

   to 
  work 
  done 
  with 
  another. 
  — 
  There 
  are 
  in 
  all 
  compasses 
  and 
  tran- 
  

   sits 
  strong 
  probabilities 
  of 
  a 
  certain 
  error 
  in 
  their 
  readings 
  of 
  mag- 
  

   netic 
  bearings 
  owing 
  to 
  the 
  fact 
  ist, 
  that 
  the 
  line 
  of 
  sights 
  is 
  not 
  

   exactly 
  in 
  line 
  with 
  the 
  zero 
  marks 
  on 
  the 
  compass 
  box 
  and 
  2d, 
  

   that 
  the 
  magnetic 
  axis 
  of 
  the 
  needle 
  does 
  not 
  exactly 
  co-incide 
  

   with 
  its 
  physical 
  axis. 
  

  

  Though 
  we 
  made 
  a 
  number 
  of 
  readings 
  at 
  various 
  parish 
  seats 
  

   and 
  elsewhere 
  and 
  though 
  we 
  took 
  the 
  precaution 
  to 
  determine 
  

   the 
  amount 
  of 
  index 
  error 
  of 
  the 
  transit 
  used, 
  yet 
  we 
  feel 
  that 
  

  

  