﻿234 
  J. 
  Bar 
  r 
  ell 
  — 
  The 
  Piedmont 
  Terraces 
  

  

  sale 
  marine 
  erosion 
  of 
  a 
  mountain 
  region," 
  as 
  he 
  tersely 
  

   put 
  it 
  in 
  a 
  marginal 
  note 
  for 
  guidance 
  on 
  this 
  point. 
  

  

  It 
  is 
  quite 
  evident 
  that 
  Professor 
  Barrell 
  was 
  led, 
  by 
  

   his 
  conclusion 
  as 
  to 
  the 
  marine 
  origin 
  of 
  the 
  terraces, 
  

   into 
  investigations 
  along 
  several 
  much 
  neglected 
  lines. 
  

   The 
  absence 
  of 
  a 
  generally 
  accepted 
  body 
  of 
  criteria 
  for 
  

   distinguishing 
  between 
  the 
  effects 
  of 
  marine 
  and 
  fluvial 
  

   denudation 
  caused 
  him 
  to 
  take 
  up 
  the 
  study 
  of 
  marine 
  

   action 
  on 
  present 
  coasts 
  of 
  different 
  character. 
  Empha- 
  

   sis 
  was 
  naturally 
  placed 
  on 
  the 
  effects 
  of 
  marine 
  plana- 
  

   tion 
  on 
  surfaces 
  characterized 
  by 
  a 
  post-maturity 
  of 
  

   form 
  developed 
  in 
  a 
  normal 
  erosion 
  cycle 
  and 
  on 
  the 
  

   determination 
  of 
  those 
  features 
  which 
  should 
  be 
  expected 
  

   to 
  endure 
  through 
  later 
  cycles 
  of 
  fluvial 
  erosion. 
  He 
  was 
  

   extending 
  an 
  earlier 
  study 
  on 
  marine 
  and 
  terrestrial 
  con- 
  

   glomerates 
  in 
  order 
  to 
  develop 
  criteria 
  for 
  the 
  determi- 
  

   nation 
  of 
  fluvial 
  conglomerates 
  that 
  had 
  been 
  reworked 
  

   by 
  the 
  sea. 
  He 
  was 
  carefully 
  studying 
  the 
  Cretaceous 
  

   and 
  Tertiary 
  sedimentary 
  deposits, 
  for 
  it 
  was 
  evident, 
  

   as 
  was 
  long 
  ago 
  pointed 
  out 
  by 
  McGree, 
  that 
  a 
  correct 
  

   interpretation 
  of 
  their 
  physical 
  history 
  would 
  go 
  far 
  

   toward 
  solving 
  the 
  physiographic 
  history 
  of 
  the 
  contem- 
  

   poraneous 
  land 
  areas. 
  Professor 
  Barrell 
  had 
  convinc- 
  

   ingly 
  demonstrated 
  his 
  ability 
  to 
  handle 
  such 
  a 
  method 
  

   of 
  attack 
  in 
  his 
  paper 
  on 
  the 
  " 
  Upper 
  Devonian 
  Delta 
  of 
  

   the 
  Appalachian 
  Geosyncline" 
  and 
  I 
  have 
  no 
  doubt 
  that 
  

   in 
  the 
  present 
  instance 
  he 
  would 
  have 
  been 
  able 
  to 
  apply 
  

   it 
  with 
  much 
  greater 
  refinement 
  because 
  the 
  problem 
  con- 
  

   tained 
  fewer 
  unknown 
  quantities. 
  

  

  It 
  is 
  clear, 
  then, 
  that 
  he 
  was 
  developing 
  several 
  groups 
  

   of 
  ideas 
  side 
  by 
  side 
  and 
  had 
  presumably 
  not 
  reached 
  

   the 
  point 
  where 
  he 
  could 
  exactly 
  judge 
  to 
  what 
  extent 
  

   any 
  conclusions 
  reached 
  along 
  these 
  lines 
  might 
  modify 
  

   his 
  early 
  views. 
  Thus, 
  such 
  inconsistencies 
  of 
  thought 
  

   as 
  may 
  exist 
  in 
  the 
  manuscript 
  he 
  left, 
  point 
  to 
  a 
  healthy 
  

   state 
  of 
  mind. 
  Moreover, 
  the 
  fact 
  that 
  he 
  was 
  following 
  

   out 
  logically 
  each 
  principle 
  and 
  its 
  deduced 
  consequences 
  

   as 
  he 
  developed 
  them 
  shows 
  that 
  he 
  was 
  not 
  wedded 
  

   to 
  any 
  one 
  fixed 
  theory 
  as 
  to 
  the 
  origin 
  of 
  the 
  Piedmont 
  

   terraces. 
  He 
  was 
  holding 
  the 
  balance, 
  indeed, 
  with 
  rare 
  

   judgment 
  between 
  apparently 
  contradictory 
  facts 
  and 
  at 
  

   all 
  times 
  keeping 
  his 
  mind 
  open 
  to 
  conviction. 
  

  

  As 
  bearing 
  on 
  this 
  matter 
  it 
  will 
  be 
  interesting, 
  per- 
  

   haps, 
  to 
  sketch 
  very 
  briefly 
  the 
  development 
  of 
  the 
  prob- 
  

  

  