﻿226 
  Geological 
  Survey 
  of 
  Louisiana 
  [Sect. 
  

  

  erosion. 
  (See 
  Plate 
  23.) 
  Numerous 
  pieces 
  were 
  scattered 
  over 
  

   the 
  dump 
  at 
  the 
  time 
  of 
  the 
  writer's 
  visit. 
  

  

  Dr. 
  A. 
  C. 
  Gill, 
  of 
  Cornell 
  University, 
  who 
  has 
  very 
  kindly 
  

   examined 
  and 
  identified 
  the 
  specimens 
  collected, 
  states 
  that 
  the 
  

   galena 
  shows 
  no 
  silver, 
  which 
  is 
  common 
  in 
  vein 
  deposits, 
  and 
  

   that 
  it 
  therefore 
  seems 
  more 
  probable 
  that 
  this 
  represents 
  a 
  

   deposition 
  from 
  sea 
  water 
  by 
  chemical 
  action. 
  The 
  manner 
  of 
  

   occurrence, 
  scattered 
  through 
  a 
  bed 
  of 
  blue 
  clay, 
  strongly 
  

   emphasizes 
  this 
  conclusion. 
  

  

  Numerous 
  finds 
  of 
  galena 
  are 
  reported 
  from 
  different 
  parts 
  of 
  

   the 
  State 
  especially 
  in 
  the 
  northern 
  parishes. 
  These 
  when 
  

   looked 
  into, 
  have 
  always 
  shown 
  that 
  the 
  lead 
  was 
  not 
  in 
  situ 
  but 
  

   had, 
  without 
  a 
  reasonable 
  doubt, 
  been 
  carried 
  there 
  by 
  the 
  

   Indians. 
  Such 
  an 
  explanation 
  will 
  not 
  apply 
  to 
  this 
  deposit. 
  

  

  Salt. 
  — 
  The 
  salt, 
  occurs 
  in 
  several 
  forms 
  ; 
  large 
  transparent 
  

   crystals 
  one 
  to 
  eight 
  or 
  more 
  inches 
  long, 
  either 
  in 
  masses, 
  where 
  

   interference 
  has 
  prevented 
  the 
  formation 
  of 
  perfect 
  crj-stals 
  or 
  

   scattered 
  through 
  dark 
  colored 
  clay, 
  as 
  in 
  the 
  upper 
  part 
  of 
  the 
  

   salt 
  mass 
  ; 
  smaller 
  crj^stals 
  in 
  masses 
  having 
  the 
  appearance 
  of 
  

   rather 
  coarse 
  crushed 
  ice 
  or 
  inclosing 
  pieces 
  of 
  dark 
  colored 
  clay 
  

   which 
  gives 
  the 
  salt 
  a 
  dirty 
  earth-like 
  appearance. 
  Occasionally 
  

   the 
  large 
  salt 
  crystals 
  show 
  crystals 
  of 
  gypsum. 
  

  

  Unlike 
  any 
  of 
  the 
  other 
  islands 
  the 
  salt 
  when 
  first 
  struck 
  on 
  

   Belle 
  Isle 
  is 
  very 
  impure 
  ; 
  its 
  purity 
  seeming 
  to 
  increase 
  with 
  

   the 
  depth. 
  The 
  black 
  material 
  which 
  is 
  abundant 
  enough 
  in 
  the 
  

   upper 
  part 
  of 
  the 
  salt 
  to 
  color 
  the 
  whole 
  mass 
  and 
  which 
  shows 
  

   some 
  traces 
  of 
  oil, 
  brings 
  to 
  mind 
  the 
  thin 
  black 
  bands 
  in 
  the 
  

   Petite 
  Anse 
  salt. 
  The 
  resemblance 
  is 
  further 
  heightened 
  by 
  the 
  

   fact 
  that 
  the 
  black 
  salt 
  on 
  Petite 
  Anse 
  shows 
  about 
  seven 
  per 
  

   cent, 
  of 
  insoluble 
  matter, 
  part 
  of 
  which 
  is 
  gypsum* 
  and 
  the 
  

   Belle 
  Isle 
  black 
  salt 
  shows 
  about 
  the 
  same 
  amount 
  of 
  insoluble 
  

   matter, 
  part 
  of 
  which, 
  although 
  a 
  much 
  smaller 
  part, 
  is 
  gypsum. 
  

  

  A7ialyses 
  of 
  salt. 
  — 
  Two 
  samples 
  of 
  salt 
  from 
  Belle 
  Isle 
  have 
  

   been 
  analyzed 
  under 
  direction 
  of 
  Mr. 
  R. 
  E. 
  Blouin 
  of 
  the 
  Experi- 
  

   ment 
  Stations. 
  To 
  these 
  records 
  we 
  have 
  added 
  for 
  the 
  purpose 
  

   of 
  comparison 
  three 
  analyses 
  of 
  .salt 
  produced 
  by 
  evaporation 
  of 
  

   sea 
  water. 
  

  

  *Notes 
  on 
  the 
  Great 
  Salt 
  Deposit 
  of 
  Petite 
  Anse, 
  Louisiana 
  (Abstract) 
  b}- 
  

   Dr. 
  H. 
  C. 
  Bolton. 
  New 
  York 
  Acad. 
  Sci. 
  Trans., 
  vol. 
  6, 
  p. 
  125, 
  1888. 
  

  

  