﻿Hay 
  — 
  Ages 
  of 
  Pleistocene 
  Deposits. 
  365 
  

  

  Of 
  those 
  who 
  insist 
  that 
  the 
  great 
  roll 
  of 
  extinct 
  species 
  

   which 
  perished 
  in 
  Florida 
  met 
  their 
  doom 
  during 
  the 
  

   prevalence 
  of 
  the 
  Wisconsin 
  ice 
  sheet 
  and 
  not 
  at 
  its 
  end, 
  

   it 
  may 
  be 
  asked 
  why 
  this 
  epoch 
  was 
  more 
  fatal 
  than 
  the 
  

   three 
  or 
  four 
  preceding 
  glacial 
  stages, 
  during 
  some 
  of 
  

   which 
  the 
  ice 
  reached 
  still 
  farther 
  south. 
  I 
  think 
  that 
  

   there 
  are 
  no 
  evidences 
  to 
  show 
  that 
  during 
  this 
  stage 
  the 
  

   climate 
  was 
  more 
  rigorous 
  than 
  during 
  earlier 
  glacial 
  

   stages; 
  and 
  it 
  is 
  probable 
  too, 
  that 
  it 
  was 
  a 
  stage 
  of 
  

   shorter 
  duration. 
  

  

  To 
  the 
  writer 
  it 
  appears, 
  therefore, 
  that 
  the 
  assign- 
  

   ment 
  of 
  the 
  formation 
  which 
  contains 
  the 
  extinct 
  fauna 
  

   referred 
  to 
  and 
  which 
  constitutes 
  the 
  lowest 
  plain 
  in 
  

   Florida, 
  Georgia, 
  and 
  South 
  Carolina, 
  to 
  the 
  last 
  glacial 
  

   epoch 
  is 
  made 
  impossible 
  by 
  the 
  character 
  of 
  the 
  fossils 
  

   contained 
  in 
  it. 
  

  

  Some 
  of 
  our 
  geological 
  friends 
  argue 
  that 
  the 
  lowest 
  

   formation 
  in 
  the 
  southern 
  States, 
  which 
  they 
  synchronize 
  

   with 
  the 
  Talbot, 
  is 
  young 
  because 
  it 
  shows 
  little 
  erosion 
  

   and 
  dissection. 
  Time, 
  however, 
  is 
  not 
  the 
  only 
  factor 
  

   in 
  the 
  production 
  of 
  erosion 
  and 
  dissection. 
  One 
  would 
  

   not 
  expect 
  much 
  diversification 
  of 
  the 
  surface 
  of 
  Dismal 
  

   Swamp 
  to 
  occur 
  in 
  a 
  million 
  years. 
  In 
  his 
  description 
  

   of 
  the 
  Sardis 
  plain, 
  in 
  southern 
  Mississippi, 
  belonging 
  to 
  

   the 
  Citronelle 
  (Pliocene) 
  formation, 
  Matson 
  4 
  says 
  that 
  

   there 
  are 
  some 
  inter 
  stream 
  plains 
  from 
  five 
  to 
  more 
  than 
  

   ten 
  miles 
  in 
  width 
  which 
  have 
  inadequate 
  drainage. 
  

   W. 
  M. 
  Davis, 
  5 
  in 
  speaking 
  of 
  an 
  area 
  which 
  has 
  reached 
  

   the 
  stage 
  of 
  a 
  peneplain, 
  says 
  that 
  "if 
  no 
  accident 
  enters 
  

   to 
  disturb 
  the 
  relation 
  of 
  mass 
  and 
  base-level, 
  the 
  area 
  

   will 
  remain 
  indefinitely 
  with 
  insignificant 
  change, 
  main- 
  

   taining, 
  like 
  the 
  Sybil, 
  an 
  immortal 
  old 
  age." 
  Contrari- 
  

   wise, 
  the 
  formation 
  which, 
  in 
  the 
  southern 
  States, 
  has 
  

   been 
  regarded 
  as 
  equivalent 
  to 
  the 
  Cape 
  May 
  and 
  Talbot 
  

   might 
  continue 
  to 
  maintain 
  an 
  immortal 
  infancy. 
  

  

  .In 
  North 
  Carolina 
  the 
  Pleistocene 
  formations 
  have 
  

   been 
  studied 
  and 
  mapped 
  by 
  Dr. 
  L. 
  W. 
  Stevenson. 
  6 
  Five 
  

   terrace 
  plains 
  are 
  recognized, 
  as 
  follows, 
  beginning 
  with 
  

   the 
  oldest 
  and 
  most 
  elevated: 
  Coharie, 
  Sunderland, 
  

   Wicomico, 
  Chowan, 
  and 
  Pamlico. 
  The 
  last 
  two 
  together 
  

   are 
  regarded 
  as 
  being 
  equivalent 
  to 
  the 
  Talbot 
  of 
  Mary- 
  

  

  4 
  U. 
  S. 
  Geol. 
  Surv., 
  Prof, 
  paper, 
  98 
  L, 
  p. 
  182. 
  

  

  5 
  Jour. 
  Geol., 
  vol. 
  2, 
  p. 
  546. 
  

  

  6 
  N. 
  C. 
  Geol. 
  Surv., 
  vol. 
  2, 
  pp. 
  266-290, 
  pi. 
  XIII, 
  1912. 
  

  

  