﻿Ill] 
  The 
  Fire 
  Islands 
  ; 
  Origin 
  261 
  

  

  wherever 
  the 
  outcrop 
  is 
  large 
  enough 
  to 
  see 
  the 
  stratigraphy, 
  a 
  

   marked 
  dome. 
  The 
  salt 
  springs 
  apparently 
  emerge 
  from 
  this 
  

   gypseous 
  limestone, 
  which 
  Hilgard, 
  on 
  two 
  fossils 
  found 
  at 
  

   King's 
  salt 
  works, 
  pronounced 
  Cretaceous. 
  Vaughan 
  on 
  very 
  

   slender 
  evidence 
  guessed 
  it 
  to 
  be 
  upper 
  Cretaceous.* 
  This 
  was 
  

   proven 
  this 
  year 
  beyond 
  question 
  by 
  a 
  large 
  suite 
  of 
  fossils 
  col- 
  

   lected 
  at 
  Rayburn's 
  salt 
  works. 
  - 
  

  

  The 
  salt 
  springs 
  of 
  northern 
  Louisiana 
  are 
  then 
  known 
  to 
  

   emerge 
  from 
  upper 
  Cretaceous 
  outcrops. 
  No 
  salt 
  springs 
  are 
  

   known 
  in 
  the 
  Tertiary 
  of 
  this 
  region 
  ; 
  therefore 
  Hilgard 
  con- 
  

   cluded 
  the 
  salt 
  to 
  be 
  Cretaceous. 
  So 
  far 
  as 
  our 
  evidence 
  goes 
  

   this 
  seems 
  the 
  most 
  probable 
  though 
  it 
  can 
  hardly 
  be 
  said 
  to 
  be 
  

   proven 
  . 
  

  

  Compariso?i 
  of 
  the 
  Louisiana 
  rock 
  salt 
  deposit 
  to 
  the 
  great 
  deposits 
  of 
  

   theworld. 
  — 
  In 
  thickness 
  and 
  purity 
  the 
  Louisiana 
  salt 
  deposit 
  easily 
  

   outranks 
  any 
  other 
  3'et 
  known 
  in 
  this 
  country. 
  In 
  Europe 
  the 
  

   famous 
  Strassfurt 
  deposits 
  of 
  Permian 
  age 
  show 
  only 
  685 
  feet 
  of 
  

   pure 
  rock 
  salt.f 
  But 
  it 
  is 
  outranked 
  by 
  the 
  salt 
  wells 
  in 
  strata 
  

   of 
  the 
  same 
  age 
  at 
  Sperenberg 
  near 
  Berlin, 
  which 
  passes 
  through 
  

   3,769 
  feet 
  of 
  rock 
  salt.+ 
  Geikie 
  gives 
  to 
  the 
  famous 
  Wieliczka 
  

   deposits 
  of 
  Gallacia, 
  Austria, 
  which 
  are 
  now 
  believed 
  to 
  be 
  Ter- 
  

   tiary, 
  § 
  possibly 
  Miocene, 
  or 
  even 
  later, 
  || 
  an 
  aggregate 
  thickness 
  

   of 
  4,600 
  feet. 
  But 
  this 
  does 
  not 
  represent 
  the 
  thickness 
  of 
  a 
  

   single 
  mass 
  of 
  salt 
  as 
  is 
  the 
  case 
  in 
  the 
  Cote 
  Carline 
  deposit. 
  

   The 
  saliferous 
  formations 
  of 
  Wieliczka 
  consist 
  of 
  layers 
  and 
  

  

  *A 
  Brief 
  Contribution 
  to 
  the 
  Geology 
  and 
  Paleontology 
  of 
  Northwestern 
  

   Louisiana 
  by 
  T. 
  Wayland 
  Vaughan. 
  Bull. 
  U. 
  S. 
  Geol. 
  Surv. 
  No. 
  142, 
  1896, 
  

   pp. 
  12-13. 
  

  

  f 
  Text 
  Book 
  of 
  Geology 
  by 
  Archibald 
  Geikie, 
  3d 
  ed., 
  London, 
  1893, 
  p. 
  148. 
  

  

  :j: 
  Geology, 
  Chemical, 
  Physical 
  and 
  Stratigraphical, 
  by 
  Joseph 
  Prestwich, 
  

   Oxford, 
  1884, 
  vol. 
  I, 
  p. 
  116, 
  vol. 
  2, 
  p. 
  140. 
  

  

  Nature, 
  vol. 
  15, 
  p. 
  240, 
  1877. 
  

  

  Hand 
  Book 
  of 
  Geology 
  by 
  A. 
  Geikie, 
  3d 
  ed., 
  London, 
  1893, 
  p. 
  148. 
  

  

  Elements 
  of 
  Geology 
  by 
  Joseph 
  LeConte, 
  4th 
  ed., 
  New 
  York, 
  1897, 
  p. 
  439. 
  

  

  § 
  A 
  System 
  of 
  Mineralogy 
  by 
  E. 
  S. 
  Dana, 
  6th 
  ed., 
  New 
  York, 
  1892, 
  p, 
  155. 
  

   Address 
  by 
  Andrew 
  Crombie 
  Ramsey. 
  Report 
  of 
  Brit. 
  Assn. 
  Adv. 
  Sci., 
  

   1880, 
  p. 
  13. 
  

  

  