﻿THE 
  

  

  AMERICAN 
  JOURNAL 
  OF 
  SCIENCE 
  

  

  [THIRD 
  SERIES.] 
  

  

  Art. 
  XXI. 
  — 
  Niagara 
  and 
  the 
  Great 
  ZaJces 
  ; 
  by 
  Frank 
  

   Bursley 
  Taylor. 
  

  

  Introduction. 
  

  

  In 
  the 
  recent 
  papers 
  of 
  Professor 
  J. 
  W. 
  Spencer* 
  and 
  Mr. 
  

   Warren 
  Upham 
  f 
  the 
  post-glacial 
  history 
  of 
  the 
  Great 
  Lakes 
  

   has 
  been 
  ably 
  told 
  according 
  to 
  two 
  very 
  different 
  ideas 
  of 
  the 
  

   cause 
  of 
  Pleistocene 
  change. 
  Prof. 
  Spencer 
  on 
  the 
  one 
  hand 
  

   levels 
  all 
  the 
  higher 
  abandoned 
  beaches 
  with 
  the 
  sea, 
  and 
  does 
  

   not 
  distinctly 
  recognize 
  a 
  single 
  ice-dammed 
  lake. 
  Mr. 
  

   Upham, 
  on 
  the 
  other 
  hand, 
  ascribes 
  nearly 
  all 
  submergence 
  

   to 
  ice-dammed 
  lakes, 
  and 
  admits 
  none 
  as 
  marine 
  except 
  that 
  

   which 
  is 
  proved 
  by 
  fossils. 
  As 
  often 
  happens 
  in 
  such 
  cases, 
  

   the 
  probability 
  is 
  that 
  the 
  truth 
  lies 
  between 
  these 
  wide 
  

   extremes. 
  Ice 
  dams 
  have 
  played 
  an 
  important 
  part, 
  but 
  not 
  

   to 
  the 
  exclusion 
  of 
  marine 
  submergence 
  even 
  at 
  high 
  levels. 
  

   On 
  the 
  other 
  hand, 
  marine 
  invasion 
  is 
  not 
  available 
  as 
  an 
  

   explanation 
  for 
  some 
  of 
  the 
  most 
  important 
  areas 
  of 
  sub- 
  

   mergence. 
  

  

  The 
  St. 
  Lawrence 
  river 
  and 
  the 
  Great 
  Lakes 
  with 
  their 
  con- 
  

   necting 
  channels 
  are 
  really 
  all 
  one 
  stream. 
  The 
  lakes 
  are 
  

   great 
  reservoirs 
  which 
  feed 
  the 
  rivers 
  below 
  them, 
  and 
  because 
  

   they 
  derive 
  nearly 
  all 
  their 
  supply 
  from 
  the 
  lakes 
  the 
  rivers 
  

  

  *''The 
  Duration 
  of 
  Niagara 
  Falls," 
  by 
  J. 
  "W. 
  Spencer, 
  this 
  Journal, 
  Dec, 
  

   1894; 
  "A 
  Review 
  of 
  the 
  Historv 
  of 
  the 
  Great 
  Lakes," 
  Am. 
  Geol., 
  vol. 
  xiv, 
  Nov., 
  

   1894. 
  

  

  f 
  ' 
  ' 
  Late 
  Glacial 
  or 
  Champlain 
  Subsidence 
  and 
  Reelevation 
  of 
  the 
  St. 
  Lawrence 
  

   River 
  Basin," 
  by 
  Warren 
  Upham, 
  this 
  Journal, 
  Jan., 
  1895 
  ; 
  Twenty-second 
  

   Ann. 
  Rep't 
  Geol. 
  and 
  Nat. 
  Hist. 
  Survey 
  of 
  Minn., 
  Part 
  III, 
  pp. 
  54-66; 
  "Depart- 
  

   ure 
  of 
  the 
  Ice-Sheet 
  from 
  the 
  Laurentian 
  Lakes," 
  Bull. 
  G. 
  S. 
  A., 
  vol. 
  vi, 
  1894. 
  

  

  Am. 
  Jour. 
  Sci.— 
  Third 
  Series, 
  Yol. 
  XLIX, 
  No. 
  292.— 
  April, 
  1895. 
  

   17 
  

  

  