﻿rl48 
  NEW 
  YOKK 
  STATE 
  MUSEUM 
  

  

  dition, 
  we 
  would 
  have 
  a 
  mature 
  stream, 
  in 
  a 
  region 
  of 
  remarkable 
  

   homogeneity 
  of 
  structure, 
  suddenly 
  dropping 
  off 
  near 
  its 
  mouth 
  at 
  a 
  

   much 
  steeper 
  grade 
  than 
  that 
  a 
  little 
  farther 
  up 
  — 
  a 
  condition 
  con- 
  

   trary 
  to 
  the 
  definition 
  of 
  a 
  mature 
  stream. 
  Therefore 
  it 
  is 
  evident 
  

   that 
  at 
  the 
  lake 
  shore 
  the 
  preglacial 
  valley 
  of 
  Payne's 
  creek 
  must 
  

   be 
  filled 
  to 
  a 
  depth 
  of 
  at 
  least 
  50 
  feet. 
  

  

  Considering 
  Salmon 
  creek 
  in 
  the 
  same 
  way, 
  we 
  have 
  a 
  still 
  more 
  

   remarkable 
  case. 
  

  

  The 
  stream 
  for 
  a 
  mile 
  and 
  a 
  half 
  above 
  its 
  moutli 
  descends 
  no 
  

   more 
  rapidly 
  than 
  Payne's 
  creek, 
  — 
  that 
  is, 
  100 
  feet 
  to 
  the 
  mile. 
  

  

  The 
  distance 
  from 
  its 
  mouth 
  to 
  the 
  center 
  of 
  the 
  lake 
  is 
  | 
  of 
  a 
  

   mile, 
  while 
  the 
  depth 
  of 
  the 
  lake 
  here 
  is 
  about 
  350 
  feet. 
  So 
  that, 
  

   if 
  the 
  main 
  preglacial 
  stream 
  flowed 
  on 
  the 
  bottom 
  of 
  the 
  lake, 
  the 
  

   old 
  creek 
  would 
  have 
  fallen 
  350 
  feet 
  in 
  f 
  of 
  a 
  mile 
  at 
  its 
  mouth 
  and 
  

   then 
  suddenly 
  have 
  changed 
  its 
  slope 
  to 
  but 
  100 
  feet 
  in 
  a 
  mile. 
  

   Surely 
  such 
  a 
  condition 
  could 
  never 
  have 
  existed 
  in 
  a 
  mature 
  

   stream, 
  as 
  this 
  unquestionably 
  was. 
  

  

  If, 
  as 
  I 
  have 
  claimed, 
  these 
  two 
  streams 
  had 
  established 
  anything 
  

   like 
  the 
  profile 
  of 
  equilibrium 
  for 
  two 
  or 
  three 
  miles 
  near 
  their 
  

   mouths, 
  with 
  the 
  slope 
  at 
  the 
  rate 
  of 
  100 
  feet 
  to 
  the 
  mile, 
  (which 
  is 
  

   many 
  times 
  greater 
  than 
  the 
  usual 
  rate 
  of 
  fall 
  of 
  a 
  mature 
  stream) 
  

   then 
  the 
  preglacial 
  main 
  stream 
  (considering 
  it 
  to 
  have 
  been 
  near 
  

   the 
  center 
  of 
  the 
  lake) 
  must 
  have 
  been 
  about 
  150 
  feet 
  above 
  the 
  

   lake 
  bottom 
  opposite 
  Payne's 
  creek, 
  and 
  more 
  than 
  250 
  feet 
  above 
  

   it 
  opposite 
  Salmon 
  creek. 
  

  

  Similar 
  evidence 
  can 
  be 
  deduced 
  from 
  several 
  other 
  preglacial 
  

   streams 
  and 
  from 
  buried 
  valleys 
  along 
  the 
  shores. 
  Bnt 
  the 
  two 
  

   given 
  are 
  typical, 
  and 
  the 
  evidence 
  of 
  the 
  others 
  is 
  not 
  needed. 
  

  

  Of 
  course 
  these 
  figures 
  are 
  deduced 
  from 
  the 
  few 
  actual 
  measure- 
  

   ments 
  it 
  is 
  possible 
  to 
  make, 
  and 
  do 
  not 
  pretend 
  to 
  be 
  exact. 
  They 
  

   are 
  introduced, 
  because 
  they 
  follow 
  logically 
  from 
  the 
  conditions 
  

   that 
  would 
  exist 
  if 
  the 
  conclusion 
  reached 
  (that 
  the 
  preglacial 
  

   stream 
  flowed 
  above 
  the 
  present 
  bottom 
  of 
  the 
  lake) 
  were 
  true, 
  and 
  

   the 
  fact 
  that 
  the 
  estimates 
  do 
  fit 
  the 
  hypothesis 
  so 
  well 
  is 
  a 
  strong 
  

   argument 
  in 
  its 
  favor. 
  

  

  As 
  to 
  what 
  caused 
  the 
  deepening 
  of 
  the 
  valley— 
  a 
  careful 
  study 
  

   convinces 
  me 
  that 
  there 
  can 
  be 
  but 
  one 
  answer 
  — 
  ice. 
  

  

  To 
  claim 
  for 
  ice 
  the 
  power 
  to 
  pass 
  up 
  a 
  stream 
  valley 
  and 
  erode 
  it 
  

   to 
  the 
  depth 
  of 
  250 
  feet 
  (as 
  off 
  Salmon 
  creek) 
  may 
  seem 
  to 
  call 
  

  

  