﻿362 
  Hay 
  — 
  Ages 
  of 
  Pleistocene 
  Deposits. 
  

  

  either 
  those 
  who 
  believe 
  that 
  the 
  low-lying 
  deposits 
  along 
  

   the 
  Atlantic 
  coast 
  of 
  the 
  southern 
  States 
  belong 
  to 
  the 
  

   late 
  Pleistocene 
  must 
  surrender 
  their 
  position 
  or 
  it 
  must 
  

   be 
  acknowledged 
  that 
  the 
  animals 
  found 
  fossil 
  in 
  them 
  

   existed 
  up 
  to 
  near 
  the 
  end 
  of 
  the 
  Pleistocene 
  or 
  later. 
  

  

  It 
  seems 
  improbable 
  that 
  the 
  early 
  Pleistocene 
  verte- 
  

   brate 
  fauna 
  remained 
  practically 
  unchanged 
  up 
  to 
  the 
  

   end 
  of 
  the 
  epoch. 
  Time 
  itself 
  is 
  a 
  powerful 
  factor 
  in 
  

   bringing 
  about 
  extinctions 
  among 
  living 
  beings. 
  All 
  

   species 
  are 
  continually 
  under 
  stress; 
  and 
  it 
  is 
  to 
  be 
  

   expected 
  that 
  normally 
  first 
  one 
  and 
  then 
  another 
  will 
  

   succumb 
  ; 
  so 
  that 
  in 
  the 
  course 
  of 
  a 
  long 
  period 
  there 
  will 
  

   result 
  a 
  more 
  or 
  less 
  gradual 
  change 
  in 
  the 
  fauna, 
  even 
  

   though 
  there 
  are 
  no 
  great 
  changes 
  in 
  the 
  environment. 
  

   During 
  the 
  course 
  of 
  the 
  Pleistocene 
  there 
  were, 
  especially 
  

   in 
  the 
  north, 
  several 
  alternations 
  of 
  climate 
  from 
  one 
  

   extreme 
  to 
  another 
  ; 
  and 
  it 
  is 
  hardly 
  probable 
  that 
  these 
  

   changes 
  did 
  not 
  affect 
  the 
  vertebrates 
  of 
  the 
  southern 
  

   States. 
  Furthermore, 
  the 
  northern 
  species 
  were 
  at 
  each 
  

   glacial 
  stage 
  forced 
  southward, 
  so 
  that 
  these 
  regions 
  

   tended 
  to 
  become 
  overpopulated. 
  Also, 
  if 
  there 
  is 
  any- 
  

   thing 
  of 
  importance 
  in 
  the 
  idea 
  that 
  northern 
  animals 
  

   are 
  more 
  hardy, 
  these 
  would 
  have 
  had 
  an 
  advantage 
  over 
  

   those 
  not 
  accustomed 
  to 
  the 
  colder 
  climate. 
  It 
  is 
  the 
  

   species 
  of 
  the 
  southern 
  States 
  which 
  especially 
  might 
  be 
  

   expected 
  to 
  have 
  gradually 
  died 
  out 
  during 
  the 
  progress 
  

   of 
  the 
  Pleistocene. 
  There 
  are 
  those 
  1 
  who 
  assert 
  that 
  the 
  

   fauna 
  in 
  question 
  belongs 
  to 
  the 
  late 
  Pleistocene 
  or 
  even 
  

   to 
  the 
  Recent. 
  If 
  such 
  an 
  assemblage 
  of 
  vertebrates 
  as 
  

   is 
  found 
  in 
  the 
  low-lying 
  formations 
  of 
  Florida, 
  Georgia, 
  

   and 
  South 
  Carolina, 
  existed 
  there 
  after 
  the 
  end 
  of 
  the 
  

   last 
  glacial 
  epoch 
  and 
  then 
  suffered 
  the 
  extinction 
  of 
  

   more 
  than 
  two-thirds 
  of 
  the 
  species, 
  some 
  adequate 
  cause 
  

   ought 
  to 
  he 
  sought 
  for 
  such 
  a 
  disaster. 
  That 
  the 
  Indians 
  

   with 
  their 
  feeble 
  weapons 
  effected 
  the 
  destruction 
  is 
  not 
  

   to 
  be 
  believed. 
  They 
  were 
  making 
  no 
  impression 
  on 
  the 
  

   game 
  animals 
  of 
  the 
  country 
  when 
  the 
  whites 
  arrived. 
  

   Nobody 
  has 
  found 
  the 
  bones 
  of 
  elephants, 
  horses, 
  or 
  

   ground-sloths 
  in 
  the 
  shell 
  heaps 
  of 
  Florida. 
  2 
  

  

  If 
  such 
  animals 
  as 
  Elephas 
  imperator, 
  the 
  camels, 
  the 
  

   tapirs, 
  horses, 
  the 
  great 
  cats, 
  the 
  saber-tooth 
  tigers, 
  the 
  

   rnylodons, 
  and 
  Bison 
  latifrons, 
  had 
  lived 
  around 
  the 
  Gulf 
  

  

  1 
  MacCurdy, 
  Jour. 
  Geol., 
  vol. 
  25, 
  p. 
  62 
  ; 
  E. 
  T. 
  Chamberlin, 
  vol. 
  cit. 
  p. 
  662. 
  

  

  2 
  Nelson, 
  Science, 
  vol. 
  46, 
  p. 
  394. 
  

  

  