﻿II] 
  Generai, 
  Geology 
  : 
  Lafayette 
  105 
  

  

  between 
  the 
  Red, 
  the 
  Ouachita 
  and 
  the 
  State 
  line 
  including 
  

   Caldwell, 
  the 
  major 
  part 
  of 
  Winn, 
  Jackson, 
  eastern 
  Bienville, 
  

   southeastern 
  Claiborne, 
  the 
  major 
  part 
  of 
  Lincoln 
  and 
  the 
  west- 
  

   ern 
  part 
  of 
  Ouachita 
  parishes 
  ; 
  (4) 
  all 
  the 
  territor}^ 
  lyi^^g 
  west 
  of 
  

   the 
  Black 
  lake 
  gravel 
  train 
  and 
  north 
  of 
  the 
  Grand 
  Gulf 
  except 
  

   the 
  area 
  about 
  Many 
  and 
  Sabinetown. 
  

  

  Thickness 
  of 
  the 
  Deposit 
  

   In 
  northern 
  Louisiana 
  exposures 
  of 
  a 
  greater 
  thickness 
  than 
  

   ID 
  or 
  20 
  feet 
  seem 
  to 
  be 
  rather 
  rare. 
  In 
  the 
  region 
  of 
  Minden 
  

   the 
  deposit 
  is 
  at 
  least 
  60 
  or 
  70 
  feet 
  thick. 
  In 
  southern 
  Louisi- 
  

   ana 
  it 
  shows 
  a 
  thickness 
  in 
  the 
  Lake 
  Charles 
  wells 
  of 
  from 
  150 
  

   to 
  over 
  200 
  feet. 
  On 
  Cote 
  Carline, 
  Grande 
  Cote 
  and 
  Belle 
  Isle 
  

   the 
  borings 
  show 
  that 
  a 
  thickness 
  of 
  200 
  feet 
  is 
  by 
  no 
  means 
  

   uncommon. 
  Hole 
  No. 
  7 
  on 
  Cote 
  Carline, 
  which 
  is 
  for 
  the 
  most 
  

   part 
  in 
  material 
  of 
  presumably 
  Lafayette 
  age, 
  is 
  442 
  feet 
  deep. 
  

   On 
  Belle 
  Isle 
  400 
  feet 
  of 
  sand 
  is 
  recorded 
  in 
  hole 
  No. 
  2. 
  

  

  Conclusions 
  

   There 
  can 
  be 
  little 
  question 
  that 
  these 
  deposits 
  were 
  all 
  formed 
  

   in 
  the 
  same 
  way 
  and 
  that 
  they 
  represent 
  shore 
  deposits. 
  There 
  

   does 
  seem, 
  however, 
  to 
  be 
  room 
  for 
  a 
  reasonable 
  doubt 
  that 
  they 
  

   were 
  formed 
  at 
  the 
  same 
  time. 
  It 
  is 
  seen 
  in 
  the 
  beginning 
  

   that 
  the 
  argument 
  for 
  the 
  unity 
  of 
  a 
  deposit 
  which 
  is 
  differenti- 
  

   ated 
  from 
  other 
  deposits 
  merely 
  by 
  the 
  presence 
  or 
  absence 
  of 
  

   chert 
  and 
  quartz 
  gravel 
  is 
  not 
  very 
  strong. 
  Hilgard 
  noticed 
  the 
  

   very 
  peculiar 
  irregularity 
  of 
  the 
  distribution 
  of 
  the 
  gravel 
  in 
  

   Mississippi 
  and 
  the 
  same 
  has 
  since 
  been 
  found 
  true 
  in 
  Alabama. 
  

   In 
  Alabama 
  gravel 
  occurs 
  to 
  a 
  very 
  limited 
  extent 
  or 
  not 
  at 
  all 
  

   (i) 
  over 
  the 
  territory 
  of 
  the 
  Rotten 
  limestone, 
  (2) 
  over 
  the 
  Black 
  

   bluff 
  or 
  basal 
  Lignitic 
  and 
  (3) 
  over 
  parts 
  of 
  the 
  Jackson 
  or 
  white 
  

   Limestone.* 
  In 
  Mississippi 
  it 
  is 
  found 
  to 
  a 
  very 
  limited 
  extent 
  

   (i) 
  over 
  the 
  territory 
  of 
  the 
  Jackson, 
  being 
  entirely 
  absent 
  in 
  

   the 
  prairies 
  ; 
  (2) 
  it 
  is 
  wanting 
  in 
  large 
  portions 
  of 
  the 
  territory 
  

   occupied 
  by 
  the 
  Rotten 
  Limestone 
  of 
  the 
  Cretaceous 
  (3) 
  in 
  the 
  

   Flatwoods 
  region 
  [Midway] 
  of 
  the 
  northeastern 
  part 
  of 
  the 
  

   State 
  f. 
  This 
  absence 
  of 
  the 
  gravel 
  from 
  the 
  most 
  calcareous 
  

  

  *Geol. 
  Surv, 
  Ala., 
  1894, 
  p. 
  68. 
  

   fMiss. 
  Rept., 
  i860, 
  p. 
  5. 
  

  

  