﻿I] 
  Historical 
  Review 
  : 
  Second 
  Period 
  31 
  

  

  the 
  bottom 
  of 
  the 
  Gulf 
  not 
  far 
  to 
  the 
  east 
  and 
  southeast 
  of 
  

   Pensacola. 
  

  

  The 
  shelf 
  along 
  the 
  northern 
  coast 
  of 
  the 
  Gulf, 
  in 
  case 
  the 
  

   bottom 
  were 
  raised 
  450 
  feet 
  would 
  be 
  converted 
  into 
  a 
  shallow 
  

   water 
  strip 
  in 
  which 
  both 
  fresh 
  water 
  and 
  marine 
  animals 
  could 
  

   have 
  no 
  safe 
  footing. 
  Add 
  to 
  this 
  the 
  partial 
  closing 
  of 
  the 
  

   Florida 
  Straits 
  and 
  the 
  Yucatan 
  Channel 
  and 
  the 
  whole 
  Gulf 
  

   would 
  have 
  become 
  inhospitable 
  for 
  its 
  marine 
  denizens. 
  

  

  The 
  first 
  report 
  on 
  the 
  Mineral 
  Resources 
  of 
  the 
  United 
  States 
  

   published 
  in 
  1883 
  contains 
  an 
  article 
  by 
  Dr. 
  Hilgard 
  on 
  the 
  

   Salines 
  of 
  lyouisiana.* 
  It 
  contains 
  a 
  complete 
  restatement 
  of 
  

   the 
  information 
  regarding 
  the 
  northern 
  salines 
  published 
  in 
  his 
  

   earlier 
  articles 
  and 
  much 
  additional 
  data 
  on 
  the 
  mining 
  opera- 
  

   tions 
  on 
  Petite 
  Anse. 
  

  

  In 
  the 
  Report 
  on 
  Cotton 
  Production 
  in 
  the 
  United 
  Statesf, 
  

   part 
  I, 
  page 
  iii, 
  et 
  seq., 
  Hilgard 
  gives 
  a 
  brief 
  summary 
  of 
  the 
  

   geological 
  features 
  of 
  the 
  State, 
  including 
  however 
  no 
  new 
  geo- 
  

   logical 
  facts. 
  The 
  soils 
  of 
  the 
  State 
  are 
  discussed 
  with 
  care, 
  and 
  

   many 
  exhaustive 
  analyses 
  of 
  the 
  same 
  are 
  given. 
  

  

  In 
  1885 
  another 
  article 
  was 
  contributed 
  by 
  Hilgard, 
  entitled, 
  

   " 
  The 
  Classification 
  and 
  Paleontology 
  of 
  the 
  United 
  States 
  Ter- 
  

   tiary 
  Deposits."! 
  This 
  article 
  was 
  inspired 
  by 
  the 
  peculiar 
  

   stratigraphy 
  of 
  O, 
  Meyer 
  and 
  the 
  answer 
  by 
  Heilprin. 
  Hilgard 
  

   does 
  not 
  believe 
  in 
  Meyer's 
  stratigraphy. 
  On 
  the 
  other 
  hand, 
  he 
  

   fully 
  sympathizes 
  with 
  Meyer 
  in 
  considering 
  many 
  of 
  Conrad's 
  

   species 
  as 
  spurious 
  or 
  as 
  varieties 
  only 
  ; 
  states 
  he 
  gave 
  up 
  send- 
  

   ing 
  Conrad 
  m.aterial 
  because 
  the 
  latter 
  would 
  describe 
  all 
  varieties 
  

   as 
  species 
  nova. 
  Again 
  and 
  finally 
  : 
  "I 
  doubt 
  if 
  there 
  exists 
  a 
  

   finer 
  opportunity 
  for 
  observing 
  the 
  evolution 
  of 
  marine 
  species 
  

   in 
  Tertiary 
  times 
  than 
  is 
  presented 
  by 
  the 
  minutely 
  differentiated 
  

   formations 
  of 
  Mississippi 
  and 
  Louisiana." 
  

  

  About 
  simultaneously 
  another 
  article 
  appeared 
  from 
  Hilgard's 
  

   pen 
  in 
  the 
  American 
  Journal 
  of 
  Science, 
  on 
  The 
  Old 
  Tertiary 
  of 
  

   the 
  Southwest. 
  "§ 
  He 
  disposes 
  of 
  Meyer's 
  ridiculous 
  stratigraphy 
  

   in 
  trans-Mississippi 
  deposits, 
  and 
  adds: 
  "But, 
  outside 
  of 
  the 
  

  

  *Pp. 
  554-565- 
  

  

  f47th 
  Cong. 
  2d 
  Sess., 
  House 
  Mis. 
  Doc, 
  No. 
  42, 
  part 
  5, 
  1884. 
  

  

  JScience, 
  vol. 
  6, 
  p. 
  44. 
  

  

  §Am. 
  Jour. 
  Sci., 
  vol. 
  30, 
  pp. 
  266-269. 
  

  

  