﻿196 
  Geological 
  Survey 
  of 
  Louisiana 
  [Sect. 
  

  

  have 
  touched 
  this 
  region 
  but, 
  with 
  the 
  exception 
  of 
  the 
  latter, 
  

   the 
  work 
  was 
  of 
  an 
  extremely 
  hasty 
  reconnaissance 
  character 
  and 
  

   our 
  knowledge 
  of 
  the 
  country 
  is 
  very 
  meagre. 
  Vaughan 
  has 
  

   republished 
  Johnson's 
  Slaughter 
  Pen 
  Bluff 
  section 
  but 
  does 
  not 
  

   seem 
  to 
  have 
  visited 
  the 
  locality.* 
  It 
  is 
  with 
  a 
  hope 
  of 
  adding 
  

   something 
  to 
  this 
  meagre 
  information 
  that 
  the 
  facts 
  on 
  the 
  old 
  

   Tertiary 
  which 
  the 
  writer 
  was 
  incidentally 
  able 
  to 
  collect, 
  while 
  

   working 
  on 
  the 
  bottoms, 
  are 
  published. 
  What 
  is 
  needed 
  is 
  a 
  

   very 
  careful 
  examination 
  of 
  the 
  northern 
  Caddo 
  hill-lands 
  ; 
  it 
  

   has 
  been 
  a 
  guessing 
  ground 
  for 
  quite 
  a 
  number 
  of 
  years. 
  

  

  Slaughter 
  Pen 
  bluff 
  section. 
  — 
  This 
  section, 
  which 
  is 
  on 
  Cross 
  

   bayou 
  just 
  above 
  the 
  water-works, 
  has 
  been 
  examined 
  by 
  both 
  

   Johnson 
  and 
  Lerch 
  and 
  as 
  has 
  been 
  stated 
  above, 
  Johnson's 
  

   section 
  has 
  been 
  republished 
  by 
  Vaughan. 
  Johnson 
  considered 
  

   it 
  a 
  part 
  of 
  Hilgard's 
  Mansfield 
  series, 
  the 
  major 
  part 
  of 
  which 
  

   is 
  now 
  known 
  to 
  be 
  L,ignitie 
  Eocene 
  ; 
  Lerch 
  referred 
  it 
  to 
  his 
  

   lower 
  Lignitic, 
  which 
  is 
  in 
  part 
  equivalent 
  to 
  the 
  Lignitic 
  and 
  

   in 
  part 
  to 
  the 
  Lower 
  Claiborne. 
  Vaughan 
  suggests 
  that 
  it 
  is 
  

   probably 
  Lignitic. 
  

  

  The 
  discovery 
  of 
  a 
  small 
  Madra 
  in 
  the 
  upper 
  part 
  of 
  the 
  

   bluff 
  and 
  the 
  general 
  resemblance 
  of 
  this 
  species 
  and 
  the 
  litho- 
  

   logical 
  character 
  of 
  the 
  material 
  to 
  Buhrstone 
  outcrops 
  in 
  

   Alabama 
  on 
  the 
  Alabama 
  river 
  has 
  led 
  Prof, 
  Harris 
  to 
  suspect 
  

   that 
  it 
  may 
  be 
  eventually 
  classed 
  as 
  Lower 
  Claiborne. 
  The 
  

   section 
  here 
  exposed 
  is 
  : 
  

  

  Section 
  at 
  Slaughter 
  Pen 
  Bluff, 
  Shreveport. 
  

  

  (Plate 
  18.) 
  

  

  9. 
  Yellow 
  claj' 
  with 
  plates 
  of 
  calcareous 
  matter 
  grading 
  above 
  

  

  into 
  red 
  soil 
  6 
  ft. 
  

  

  8. 
  Gray 
  calcareous 
  concretions 
  2 
  ft. 
  

  

  7. 
  Grayish 
  and 
  yellow 
  sandy 
  claj^ 
  with 
  leaves 
  and 
  shells. 
  . 
  5 
  ft. 
  

   6. 
  Fine 
  lamellae 
  of 
  brown 
  clay 
  and 
  yellowish 
  graj^ 
  sand 
  

  

  with 
  reddish 
  iron 
  nodules 
  5 
  ft. 
  

  

  5. 
  Same 
  as 
  No 
  6 
  but 
  without 
  iron 
  nodules. 
  Contains 
  

  

  large 
  log 
  of 
  silicified 
  wood 
  6 
  ft. 
  

  

  4. 
  Dark 
  drab 
  clay 
  2 
  ft. 
  

  

  *Am. 
  Geol., 
  vol. 
  15, 
  1895, 
  p. 
  205; 
  also 
  Bull. 
  U. 
  S. 
  Geo!. 
  Surv., 
  

   No. 
  142, 
  1896. 
  

  

  