﻿REPORT 
  OF 
  THE 
  DIRECTOR 
  r77 
  

  

  instances 
  this 
  type 
  of 
  terrace 
  has 
  been 
  formed 
  by 
  accident 
  at 
  one 
  or 
  

   more 
  of 
  the 
  higher 
  lake 
  levels, 
  and 
  by 
  static 
  water 
  modification 
  

   possibly 
  transformed 
  into 
  a 
  lake 
  shoreline. 
  This 
  is 
  shown 
  along 
  

   the 
  south 
  side 
  of 
  Six 
  Mile 
  creek, 
  beginning 
  at 
  the 
  east 
  side 
  of 
  the 
  

   Inlet 
  valley 
  just 
  out 
  of 
  the 
  city 
  limits 
  of 
  Ithaca, 
  and 
  forming 
  the 
  

   juncture 
  of 
  the 
  two 
  valleys; 
  and, 
  is 
  again 
  marked 
  along 
  the 
  south 
  

   and 
  east 
  side 
  of 
  Cascadilla 
  creek, 
  which 
  marks 
  the 
  beginning 
  of 
  the 
  

   divide 
  between 
  Six 
  Mile 
  and 
  Cascadilla 
  creeks. 
  

  

  Statement 
  of 
  the 
  possibilities 
  

  

  During. 
  the 
  entire 
  progress 
  of 
  the 
  field 
  work 
  the 
  writer 
  has 
  con- 
  

   stantly 
  borne 
  in 
  mind 
  all 
  possible 
  hypotheses 
  by 
  which 
  the 
  conditions 
  

   might 
  be 
  explained. 
  A 
  large 
  amount 
  of 
  data 
  has 
  been 
  accumu- 
  

   lated, 
  which 
  will 
  be 
  stated 
  as 
  we 
  have 
  need 
  for 
  it 
  and 
  will 
  find 
  its 
  

   proper 
  place 
  in 
  a 
  subsequent 
  part 
  of 
  the 
  discussion. 
  Three 
  and 
  

   only 
  three, 
  hypotheses 
  have 
  appealed 
  to 
  him 
  as 
  being 
  at 
  all 
  plausible 
  

   in 
  explaining 
  the 
  facts. 
  They 
  may 
  be 
  stated 
  as 
  follows 
  : 
  

  

  1 
  The 
  whole 
  or 
  a 
  part 
  of 
  the 
  terraces 
  are 
  glacial 
  or 
  morainal 
  

  

  terraces. 
  This 
  hypothesis 
  necessitates 
  the 
  former 
  existence 
  of 
  

   a 
  glacial 
  tongue, 
  partially 
  filling 
  the 
  valley, 
  against 
  which 
  allu- 
  

   vial 
  deposits 
  were 
  built; 
  a 
  subsequent 
  entire 
  or 
  partial 
  with- 
  

   drawal 
  of 
  the 
  tongue 
  brings 
  the 
  deposit 
  to 
  the 
  angle 
  of 
  rest, 
  

   assuming 
  in 
  part 
  the 
  form 
  and 
  outline 
  of 
  a 
  delta. 
  Generally 
  

   a 
  portion 
  of 
  the 
  terrace 
  material 
  is 
  derived 
  from 
  the 
  glacier. 
  

  

  2 
  A 
  condition 
  of 
  marginal 
  lakes 
  due 
  to 
  differential 
  wastage 
  of 
  a 
  

  

  stagnant 
  ice 
  tongue 
  or 
  lobe, 
  mostly 
  along 
  the 
  ice 
  and 
  land 
  

   contact. 
  

  

  3 
  A 
  general 
  lake 
  condition. 
  This 
  hypothesis 
  postulates 
  a 
  north- 
  

  

  ward 
  withdrawal 
  of 
  the 
  ice-lobe, 
  acting 
  as 
  a 
  northern 
  dam 
  or 
  

   barrier 
  to 
  the 
  north 
  flowing 
  waters 
  and 
  holding 
  them 
  up 
  to 
  

   the 
  levels 
  of 
  their 
  respective 
  divides, 
  thereby 
  reversing 
  the 
  

   drainage 
  to 
  the 
  Chemung-Susquehanna 
  system, 
  until 
  the 
  ice 
  

   had 
  nearly 
  or 
  entirely 
  uncovered 
  the 
  Finger-lake 
  region. 
  Or, 
  

   as 
  may 
  have 
  been 
  the 
  case 
  in 
  some 
  of 
  the 
  lower 
  stages 
  the 
  

   outlet 
  was 
  to 
  the 
  north, 
  and 
  was 
  possibly 
  either 
  super- 
  

   glacial 
  or 
  susglacial, 
  or, 
  both. 
  

  

  