﻿2 
  W. 
  Upham 
  — 
  Champlain 
  Subsidence 
  and 
  

  

  Evidence 
  from 
  the 
  Beaches 
  of 
  the 
  Glacial 
  Lakes 
  in 
  the 
  St. 
  

   Lawrence 
  basin. 
  

  

  Well 
  marked 
  old 
  channels 
  of 
  outflow 
  are 
  fonnd 
  extending 
  

   southward, 
  at 
  the 
  levels 
  of 
  the 
  deserted 
  beaches, 
  from 
  Lake 
  

   Agassiz 
  and 
  from 
  the 
  glacial 
  lakes 
  which 
  are 
  now 
  represented 
  

   by 
  the 
  diminished, 
  but 
  still 
  large, 
  modern 
  lakes 
  Superior, 
  Michi- 
  

   gan, 
  Huron, 
  Erie, 
  Ontario, 
  and 
  Champlain. 
  The 
  outlets 
  prove 
  

   that 
  the 
  great 
  Pleistocene 
  water 
  bodies 
  which 
  occupied 
  these 
  

   basins 
  were 
  lakes, 
  not 
  gulfs 
  or 
  arms 
  of 
  the 
  sea 
  ; 
  and 
  the 
  differ- 
  

   ential 
  uplifts 
  of 
  the 
  basins, 
  increasing 
  toward 
  the 
  central 
  part 
  

   of 
  the 
  area 
  of 
  the 
  continental 
  ice-sheet, 
  show 
  that 
  no 
  land 
  bar- 
  

   riers, 
  but 
  the 
  ice 
  itself 
  in 
  its 
  retreat, 
  held 
  in 
  these 
  lakes 
  on 
  

   their 
  northward 
  sides. 
  

  

  The 
  basin 
  of 
  the 
  St. 
  Lawrence 
  during 
  the 
  glacial 
  recession 
  

   held 
  successively, 
  and 
  in 
  part 
  contemporaneously, 
  no 
  less 
  than 
  

   eight 
  important 
  glacial 
  lakes, 
  distinguished 
  by 
  their 
  different 
  

   areas, 
  heights, 
  and 
  places 
  of 
  outlet. 
  They 
  are 
  named 
  the 
  

   Western 
  Superior 
  and 
  Western 
  Erie 
  glacial 
  lakes 
  ; 
  Lake 
  

   Warren, 
  the 
  most 
  extensive, 
  into 
  which 
  the 
  two 
  foregoing 
  

   were 
  merged 
  ; 
  Lake 
  Algonquin, 
  the 
  successor 
  of 
  Lake 
  Warren 
  

   in 
  the 
  basins 
  of 
  Lakes 
  Huron, 
  Michigan, 
  and 
  Superior 
  ; 
  Lake 
  

   Lundy, 
  the 
  glacial 
  representative 
  of 
  Lake 
  Erie 
  ; 
  Lake 
  Iroquois, 
  

   in 
  the 
  basin 
  of 
  Lake 
  Ontario 
  ; 
  Lake 
  Hudson-Champlain 
  ; 
  and 
  

   Lake 
  St. 
  Lawrence, 
  into 
  which 
  the 
  two 
  last 
  named 
  became 
  

   merged. 
  The 
  glacial 
  Lake 
  St. 
  Lawrence, 
  which 
  is 
  the 
  only 
  

   one 
  of 
  the 
  series 
  hitherto 
  unnamed, 
  extended 
  over 
  the 
  Ottawa, 
  

   Champlain, 
  and 
  St. 
  Lawrence 
  valleys 
  previous 
  to 
  the 
  melting 
  

   away 
  of 
  the 
  ice 
  barrier, 
  remaining 
  latest 
  in 
  the 
  vicinity 
  of 
  

   Quebec, 
  by 
  which 
  event 
  the 
  sea, 
  at 
  a 
  lower 
  level 
  than 
  the 
  

   former 
  lake, 
  was 
  admitted 
  to 
  these 
  valleys. 
  

  

  The 
  Western 
  Superior 
  glacial 
  lake* 
  — 
  In 
  the 
  west 
  part 
  of 
  

   the 
  basin 
  of 
  Lake 
  Superior 
  the 
  receding 
  ice-sheet 
  held 
  a 
  lake 
  

   which 
  outflowed 
  southward 
  through 
  northwestern 
  Wisconsin, 
  

   across 
  the 
  present 
  watershed 
  between 
  the 
  Bois 
  Brule 
  and 
  St. 
  

   Croix 
  rivers. 
  The 
  highest 
  shore 
  line 
  of 
  this 
  lake 
  at 
  Duluth 
  is 
  

   535 
  feet 
  above 
  Lake 
  Superior 
  (which 
  has 
  a 
  mean 
  level 
  602 
  feet 
  

   above 
  the 
  sea) 
  ; 
  on 
  Mt. 
  Josephine, 
  about 
  130 
  miles 
  northeast 
  

   from 
  Duluth, 
  its 
  height, 
  according 
  to 
  leveling 
  by 
  Dr. 
  A. 
  C. 
  

   Lawson,f 
  is 
  607 
  feet 
  ; 
  and 
  at 
  L'Anse 
  and 
  Marquette, 
  Mich., 
  

   175 
  and 
  225 
  miles 
  east 
  of 
  Duluth, 
  it 
  is 
  found 
  by 
  Mr. 
  F. 
  B. 
  

   Taylor:); 
  about 
  590 
  feet 
  above 
  the 
  lake. 
  The 
  northeastward 
  

  

  *Proc. 
  A. 
  A. 
  A. 
  S., 
  vol. 
  xxxii, 
  for 
  1883, 
  p. 
  230. 
  Geo], 
  and 
  Nat. 
  Hist. 
  Survey 
  

   of 
  Minnesota, 
  Final 
  Report, 
  vol. 
  ii, 
  1888, 
  p. 
  642; 
  Twenty-second 
  Ann. 
  Rep. 
  for 
  

   1893, 
  pp. 
  54-66 
  (first 
  use 
  of 
  this 
  name). 
  Bulletin 
  Geol. 
  Soc. 
  Am., 
  vol. 
  ii, 
  1891, 
  

   p. 
  258. 
  Am. 
  Geologist, 
  vol. 
  xi. 
  p. 
  357, 
  May, 
  1893 
  ; 
  and 
  vol. 
  xiv, 
  p. 
  63, 
  July, 
  1894^ 
  

  

  f 
  Minnesota 
  Geol. 
  Survey, 
  Twentieth 
  Ann. 
  Rep. 
  for 
  1891, 
  pp. 
  181-289, 
  with 
  

   map 
  and 
  profiles. 
  

  

  \ 
  Am. 
  Geologist, 
  vol. 
  xiii, 
  pp. 
  316-327 
  and 
  365-383, 
  with 
  maps, 
  May 
  and 
  June, 
  

   1894. 
  

  

  