﻿198 
  Geological 
  Survey 
  of 
  Louisiana 
  [Sect. 
  

  

  Kansas 
  City, 
  Pittsburg 
  and 
  Gulf 
  Railroad 
  cut 
  south 
  of 
  Cross 
  Lake 
  

   bridge. 
  — 
  The 
  large 
  cut 
  on 
  the 
  Kansas 
  City, 
  Pittsburg 
  and 
  Gulf 
  

   Railroad 
  about 
  midway 
  between 
  the 
  Cross 
  lake 
  bridge 
  and 
  the 
  

   railroad 
  shops 
  shows 
  a 
  very 
  peculiar 
  collection 
  of 
  great 
  rolled 
  

   clay 
  boulders 
  in 
  a^ray 
  and 
  brown 
  sand. 
  Near 
  the 
  northern 
  end 
  

   of 
  the 
  cut 
  are 
  about 
  eight 
  feet 
  of 
  interstratified 
  orange, 
  yellow, 
  

   gray 
  and 
  brown 
  sands 
  and 
  chocolate 
  colored 
  clays. 
  The 
  clay 
  

   strata 
  are 
  quite 
  thin 
  not 
  over 
  two 
  inches 
  thick 
  in 
  any 
  case 
  

   (layer 
  A, 
  fig. 
  5). 
  The 
  layer 
  just 
  above 
  this, 
  B, 
  is 
  a 
  very 
  black 
  

   lignitic 
  clay. 
  As 
  this 
  approaches 
  the 
  fault 
  line 
  it 
  becomes 
  lighter 
  

   and 
  grades 
  into 
  a 
  brown 
  sand. 
  

  

  This 
  fault 
  only 
  extends 
  half 
  way 
  to 
  the 
  surface. 
  The 
  dis- 
  

   turbance 
  along 
  the 
  fault 
  line 
  increases 
  toward 
  the 
  bottom 
  where 
  

   the 
  layers 
  are 
  much 
  crumpled 
  and 
  broken 
  up. 
  Layer 
  D 
  is 
  made 
  

   up 
  entirely 
  of 
  grayish 
  yellow 
  sand 
  with 
  thin 
  pastings 
  of 
  blue 
  

   clay. 
  In 
  this 
  are 
  the 
  large 
  concretionary 
  masses 
  of 
  calcareous 
  

   sandstone 
  which 
  are 
  so 
  well 
  developed 
  in 
  the 
  first 
  cut 
  to 
  the 
  

   south 
  and 
  indeed 
  in 
  all 
  the 
  region 
  about 
  Shreveport. 
  

  

  The 
  southern 
  end 
  of 
  the 
  cut 
  is 
  composed 
  of 
  blue 
  claj'- 
  

   boulders 
  scattered 
  through 
  a 
  gray 
  and 
  brown 
  sand. 
  These 
  

   masses 
  of 
  blue 
  clay 
  are 
  rounded 
  and 
  the 
  stratification 
  lines 
  lie 
  in 
  

   every 
  direction. 
  Some 
  are 
  of 
  large 
  size 
  several 
  measuring 
  25 
  

   by 
  15 
  inches. 
  The 
  outer 
  portions 
  of 
  this 
  clay 
  show 
  a 
  rim 
  of 
  

   yellow 
  clay 
  an 
  inch 
  thick, 
  which 
  has 
  been 
  produced 
  by 
  oxida- 
  

   tion. 
  Many 
  of 
  the 
  clay 
  pebbles 
  have 
  coats 
  of 
  iron 
  oxide. 
  

   Through 
  the 
  mass 
  are 
  often 
  beds 
  of 
  sand, 
  one 
  very 
  noticeable 
  

   one, 
  G, 
  extends 
  diagonally 
  from 
  the 
  top 
  to 
  the 
  bottom 
  of 
  the 
  

   cut. 
  Through 
  it 
  are 
  scattered 
  very 
  small 
  clay 
  pebbles. 
  

  

  These 
  blue 
  clay 
  gravels 
  are 
  shown 
  also 
  in 
  some 
  of 
  the 
  cuts 
  

   between 
  this 
  cut 
  and 
  the 
  lake. 
  They 
  are 
  also 
  exposed 
  in 
  the 
  

   road 
  side 
  a 
  little 
  east 
  of 
  Jewella. 
  

  

  It 
  is 
  diffcult 
  to 
  conceive 
  the 
  exact 
  conditions 
  under 
  which 
  these 
  

   large 
  clay 
  bowlder 
  were 
  fashioned 
  out 
  and 
  transported 
  to 
  this 
  

   place. 
  Vaughan 
  describes 
  an 
  almost 
  identical 
  exposure 
  contain- 
  

   ing 
  large 
  clay 
  bowlders 
  at 
  Port 
  Caddo, 
  Texas, 
  and 
  concludes 
  that 
  

   it 
  represents 
  a 
  local 
  unconformity 
  of 
  Eocene 
  age.* 
  If 
  the 
  beds 
  

   at 
  Slaughter 
  Pen 
  bluff 
  are 
  of 
  Lower 
  Claiborne 
  age 
  the 
  uncon- 
  

  

  * 
  Am. 
  Geol., 
  vol. 
  16, 
  1895, 
  pp. 
  304-308. 
  

  

  i 
  

  

  