﻿r80 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  assume 
  the 
  angle 
  of 
  rest 
  or 
  repose, 
  generally 
  causing 
  a 
  considerable 
  

   settling 
  for 
  this 
  part 
  of 
  the 
  terrace. 
  I 
  have 
  been 
  unable 
  to 
  detect 
  

   any 
  such 
  necessary 
  movement. 
  

  

  To 
  sum 
  up 
  the 
  characteristics 
  of 
  a 
  moraine 
  terrace, 
  we 
  find 
  them 
  

   to 
  be 
  : 
  (1), 
  in 
  some 
  cases 
  a 
  composite 
  form, 
  that 
  is, 
  constructed 
  from 
  

   both 
  land 
  and 
  glacial 
  derived 
  material. 
  (2), 
  The 
  terrace 
  front 
  is 
  

   either 
  a 
  smooth 
  flowing 
  frontal 
  outline, 
  or, 
  most 
  generally, 
  a 
  

   hummocky 
  morainal 
  outline. 
  From 
  either 
  condition 
  would 
  follow 
  

   the 
  al^senee 
  of 
  a 
  serrated 
  margin. 
  (3), 
  A 
  settling 
  or 
  shoving 
  motion 
  

   as 
  manifested 
  in 
  the 
  frontal 
  portion 
  of 
  the 
  terrace 
  after 
  the 
  retreat 
  of 
  

   the 
  ice. 
  (4), 
  Closely 
  simulating 
  the 
  stream 
  terrace 
  as 
  regards 
  sur- 
  

   face 
  slope 
  on 
  the 
  terrace 
  top 
  and 
  not 
  having 
  the 
  true 
  flat 
  topped 
  

   outline 
  so 
  characteristic 
  of 
  delta 
  terraces. 
  These 
  characteristics, 
  

   from 
  the 
  writer's 
  observations, 
  do 
  not 
  enter 
  into 
  the 
  make 
  up 
  of 
  the 
  

   Finger-lake 
  terraces. 
  Thus, 
  it 
  is 
  evident 
  that 
  this 
  hypothesis 
  is 
  

   entirely 
  at 
  variance 
  with 
  the 
  facts, 
  and 
  can, 
  therefore, 
  be 
  eliminated 
  

   and 
  precluded 
  from 
  the 
  possibilities, 
  as 
  being 
  entirely 
  inadequate 
  to 
  

   explain 
  the 
  terraces. 
  

  

  Marginal 
  lake 
  hypothesis 
  

  

  The 
  second 
  hypothesis 
  postulates 
  the 
  existence 
  of 
  marginal 
  lakes 
  

   into 
  which 
  the 
  streams 
  poured 
  and 
  in 
  this 
  manner 
  built 
  up 
  the 
  

   existing 
  delta 
  terraces. 
  The 
  occurrence 
  of 
  marginal 
  lakes 
  along 
  the 
  

   ice 
  border 
  is 
  by 
  no 
  means 
  an 
  exceptional 
  and 
  rare 
  feature 
  but, 
  on 
  the 
  

   other 
  hand, 
  is 
  in 
  many 
  instances 
  found 
  to 
  be 
  one 
  of 
  the 
  marginal 
  

   associates. 
  There 
  are 
  many 
  wa^^s 
  by 
  which 
  this 
  kind 
  of 
  lake 
  may 
  

   be 
  formed, 
  dependent 
  largely 
  if 
  not 
  entirely 
  upon 
  the 
  topographic 
  

   relations 
  of 
  the 
  land 
  to 
  the 
  ice. 
  No 
  matter 
  in 
  what 
  ways 
  these 
  lakes 
  

   are 
  called 
  into 
  existence, 
  they 
  seldom 
  assume 
  very 
  large 
  dimensions, 
  

   comparatively 
  speaking, 
  but 
  are 
  usually 
  of 
  medium 
  or 
  small 
  dimen- 
  

   sions, 
  grading 
  from 
  a 
  mere 
  pond 
  up 
  to 
  a 
  moderate 
  sized 
  lake. 
  

  

  In 
  a 
  narrow 
  longitudinal 
  valley 
  similar 
  to 
  the 
  ones 
  studied 
  here, 
  

   and 
  down 
  which 
  ice 
  tongues, 
  were 
  protruded, 
  marginal 
  lakes 
  of 
  two 
  

   kinds 
  are 
  capable 
  of 
  being 
  formed. 
  

  

  (a). 
  Separate 
  and 
  independent 
  lakes 
  formed 
  along 
  the 
  lateral 
  con- 
  

   tact 
  between 
  the 
  land 
  and 
  ice, 
  where 
  tributar3^ 
  streams 
  en- 
  

   tered 
  and 
  thereby 
  augmented 
  the 
  wastage 
  in 
  the 
  ice. 
  Or, 
  

  

  