﻿rl44 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Their 
  radiated 
  arrangement, 
  in 
  my 
  opinion, 
  admits 
  of 
  bnt 
  one 
  

   explanation, 
  namely, 
  that 
  they 
  were 
  cut 
  by 
  one 
  and 
  the 
  same 
  glacier, 
  

   whose 
  margin 
  was 
  broken 
  into 
  several 
  streams 
  in 
  crossing 
  the 
  

   mountain 
  ridge." 
  

  

  Chamberlin, 
  a 
  leader 
  of 
  the 
  modern 
  school 
  of 
  glacial 
  geologists, 
  

   holds 
  the 
  same 
  view. 
  He 
  writes 
  : 
  

  

  "' 
  " 
  That 
  these 
  troughs 
  were 
  the 
  preglacial 
  channels 
  of 
  streams 
  

   does 
  not 
  seem 
  to 
  me 
  to 
  admit 
  of 
  reasonable 
  doubt 
  ; 
  but 
  that 
  there 
  

   was 
  a 
  selection 
  and 
  moulding 
  of 
  glacial 
  corrasion 
  seems 
  equally 
  

   clear, 
  those 
  channels 
  that 
  lay 
  in 
  the 
  direction 
  that 
  would 
  have 
  been 
  

   pursued 
  had 
  the 
  ice 
  moved 
  on 
  a 
  uniform 
  floor, 
  being 
  ground 
  out 
  

   wider, 
  deeper, 
  straighter 
  and 
  smoother, 
  while 
  those 
  in 
  a 
  transverse 
  

   direction 
  were 
  measurablv 
  tilled 
  and 
  obscured. 
  The 
  whole 
  region 
  

   shows, 
  in 
  a 
  most 
  beautiful 
  manner, 
  the 
  subduing, 
  softening 
  effects 
  of 
  

   glacial 
  grinding 
  and 
  deposition, 
  without 
  the 
  obliteration 
  of 
  the 
  

   bolder 
  features 
  of 
  the 
  preglacial 
  configuration." 
  

  

  Wright 
  rather 
  inclines 
  to 
  the 
  opposite 
  view, 
  agreeing 
  with 
  

   Spencer 
  and 
  Upham, 
  when 
  they 
  use 
  the 
  fact 
  that 
  the 
  bottoms 
  of 
  

   these 
  lakes 
  are 
  below 
  sea 
  level 
  as 
  evidence 
  of 
  a 
  preglacial 
  elevation 
  

   and 
  post-glacial 
  depression 
  of 
  the 
  district. 
  

  

  Wright 
  says 
  ^ 
  " 
  The 
  ice 
  movement 
  naturally 
  centered 
  itself 
  

   more 
  or 
  less 
  in 
  these 
  north 
  and 
  south 
  valleys, 
  and 
  hence 
  somewhat 
  

   enlarged 
  them, 
  but 
  probably 
  did 
  not 
  deepen 
  them. 
  The 
  ice, 
  how- 
  

   ever, 
  did 
  prevent 
  them 
  from 
  becoming 
  filled 
  with 
  sediment, 
  and, 
  on 
  

   its 
  final 
  retreat, 
  gave 
  place 
  to 
  water." 
  

  

  " 
  Ramsay 
  writes 
  that 
  the 
  basins 
  are 
  not 
  entirely 
  ice 
  worn, 
  as 
  is 
  

   proved 
  by 
  the 
  presence 
  of 
  the 
  large 
  number 
  of 
  preglacial 
  tributaries 
  

   flowing 
  in 
  all 
  directions. 
  It 
  is 
  not 
  strange 
  that 
  this, 
  taken 
  in 
  con- 
  

   nection 
  with 
  the 
  general 
  form 
  of 
  the 
  lake 
  valleys 
  and 
  their 
  resemb- 
  

   lance 
  to 
  mature 
  valleys 
  outside 
  of 
  the 
  glacial 
  belt, 
  should 
  have 
  led 
  

   those 
  who 
  have 
  taken 
  a 
  cursory 
  glance 
  at 
  the 
  region 
  to 
  conclude 
  

   that 
  the 
  lakes 
  are 
  merely 
  drift-dammed 
  rivers 
  ; 
  particularly 
  as 
  the 
  

   general 
  opinion 
  has, 
  of 
  late 
  years, 
  been 
  turning 
  away 
  from 
  the 
  

   belief 
  in 
  glacial 
  rock 
  basin 
  erosion, 
  since 
  so 
  few 
  instances 
  of 
  this 
  

   work 
  have 
  been 
  definitely 
  proven, 
  though 
  the 
  theory 
  has 
  been 
  

   before 
  us 
  for 
  30 
  years. 
  

  

  a 
  U. 
  S. 
  geol. 
  sur. 
  8rd 
  an. 
  rep. 
  1883, 
  p. 
  858 
  

  

  6 
  " 
  Man 
  and 
  the 
  glacial 
  period 
  " 
  1892 
  p. 
  94 
  and 
  " 
  Ice 
  age 
  in 
  N. 
  A." 
  p. 
  328 
  

  

  c 
  Quart, 
  jour. 
  geol. 
  soc. 
  Vol. 
  18. 
  1892 
  p. 
  185 
  

  

  