﻿230 
  J. 
  Barrell 
  — 
  The 
  Piedmont 
  Terraces 
  

  

  plish 
  his 
  purpose 
  in 
  the 
  shortest 
  time. 
  That 
  he 
  was 
  able 
  

   to 
  present 
  the 
  subject 
  in 
  so 
  comprehensive 
  a 
  manner 
  by 
  

   the 
  end 
  of 
  1912 
  must 
  have 
  been 
  due 
  in 
  a 
  large 
  degree 
  to 
  

   the 
  fact 
  that 
  it 
  had 
  been 
  in 
  mind 
  for 
  many 
  years. 
  He 
  

   had 
  accumulated 
  so 
  many 
  relevant 
  facts 
  that 
  when 
  he 
  

   discovered 
  the 
  terraces 
  in 
  western 
  Connecticut 
  and 
  rec- 
  

   ognized 
  their 
  probable 
  marine 
  origin 
  he 
  was 
  able 
  to 
  reach 
  

   general 
  conclusions, 
  which 
  he 
  was 
  convinced 
  were 
  cor- 
  

   rect, 
  with 
  a 
  minimum 
  of 
  systematic 
  field 
  work. 
  He 
  was 
  

   thus 
  led 
  to 
  publish 
  his 
  conclusions 
  in 
  preliminary 
  form 
  

   in 
  1912 
  and 
  to 
  postpone 
  systematic 
  field 
  study 
  until 
  the 
  

   opportunity 
  should 
  arise 
  for 
  giving 
  it 
  his 
  uninterrupted 
  

   attention. 
  He 
  fully 
  realized 
  that 
  the 
  evidence 
  he 
  had 
  

   gathered 
  was 
  only 
  sufficient, 
  so 
  far 
  as 
  others 
  were 
  con- 
  

   cerned, 
  to 
  give 
  his 
  main 
  conclusion 
  — 
  as 
  to 
  the 
  marine 
  

   origin 
  of 
  the 
  terraces 
  — 
  the 
  status 
  of 
  a 
  working 
  hypothe- 
  

   sis 
  and 
  that 
  much 
  additional 
  field 
  work 
  was 
  required 
  to 
  

   confirm 
  or 
  deny 
  it. 
  

  

  The 
  opportunity 
  to 
  take 
  up 
  the 
  work 
  again 
  in 
  earnest 
  

   did 
  not 
  present 
  itself 
  until 
  1918 
  when 
  a 
  sabbatical 
  year 
  

   gave 
  him 
  the 
  additional 
  time 
  which 
  he 
  had 
  long 
  desired. 
  2 
  

   In 
  the 
  latter 
  part 
  of 
  that 
  year 
  he 
  put 
  a 
  considerable 
  

   number 
  of 
  maps 
  and 
  profiles 
  in 
  form 
  for 
  publication 
  

   and 
  began 
  a 
  first 
  draft 
  of 
  discussions 
  of 
  the 
  principles 
  

   involved 
  in 
  the 
  analysis 
  of 
  the 
  relief 
  of 
  the 
  seaward 
  slope 
  

   of 
  the 
  Appalachians. 
  He 
  had 
  planned 
  field 
  work 
  for 
  the 
  

   summer 
  of 
  1919 
  which 
  embraced 
  a 
  study 
  of 
  (a) 
  compos- 
  

   ite 
  valley 
  slopes 
  in 
  Connecticut 
  and 
  Pennsylvania, 
  (b) 
  

   wind 
  gaps 
  especially 
  in 
  Pennsylvania, 
  (c) 
  baseleveis 
  on 
  

   the 
  Delaware 
  beginning 
  with 
  the 
  Somerville, 
  (d) 
  the 
  slate 
  

   belt 
  between 
  the 
  Susquehanna 
  and 
  the 
  Delaware 
  in 
  rela- 
  

   tion 
  to 
  the 
  Harrisburg 
  peneplain. 
  He 
  had 
  also 
  planned 
  

   to 
  devote 
  the 
  summer 
  of 
  1920 
  to 
  field 
  work. 
  It 
  should 
  

   be 
  noted 
  that 
  he 
  also 
  spent 
  a 
  short 
  time 
  in 
  the 
  field 
  in 
  

   1915 
  studying 
  the 
  uplands 
  in 
  Sullivan 
  County, 
  N. 
  Y., 
  

   where 
  they 
  are 
  developed 
  on 
  nearly 
  horizontal 
  strata. 
  

   The 
  early 
  months 
  of 
  1919 
  were 
  spent 
  on 
  the 
  preparation 
  

   of 
  his 
  manuscript, 
  interrupted 
  temporarily 
  by 
  the 
  writ- 
  

   ing 
  of 
  a 
  paper 
  on 
  isostasy, 
  and 
  he 
  had 
  planned 
  to 
  con- 
  

  

  2 
  During 
  the 
  interval 
  1913-1918 
  the 
  problem 
  was, 
  however, 
  much 
  in 
  his 
  

   mind 
  and 
  various 
  points 
  are 
  treated 
  in 
  articles 
  he 
  was 
  then 
  publishing, 
  

   namely, 
  " 
  Upper 
  Devonian 
  Delta 
  of 
  the 
  Appalachian 
  Geosyneline 
  ' 
  ; 
  (1913- 
  

   1914), 
  "Khythms 
  and 
  the 
  Measurement 
  of 
  Geologic 
  Time" 
  (1917), 
  and 
  

   "Factors 
  in 
  the 
  Movement 
  of 
  the 
  Strand-line 
  and 
  their 
  results 
  in 
  the 
  

   Pleistocene 
  and 
  Post-Pleistocene. 
  

  

  