﻿rl46 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  As 
  Prof. 
  Tarr 
  says 
  : 
  — 
  " 
  " 
  On 
  the 
  lake 
  shore 
  and 
  in 
  the 
  side 
  

   gorges, 
  the 
  shale 
  can 
  be 
  traced 
  in 
  outcrops 
  with 
  practical 
  continuity 
  

   to 
  the 
  mouth 
  of 
  this 
  valley 
  on 
  either 
  side, 
  so 
  that 
  the 
  preglacial 
  

   continuation 
  of 
  the 
  valley 
  is 
  not 
  buried 
  beneath 
  drift 
  in 
  the 
  present 
  

   hillside. 
  There 
  is 
  no 
  gap 
  in 
  the 
  series 
  of 
  outcrops 
  with 
  a 
  width 
  of 
  

   more 
  than 
  200 
  yards." 
  

  

  The 
  rock 
  bottom 
  of 
  Salmon 
  creek 
  can 
  be 
  traced 
  very 
  nearly 
  to 
  

   the 
  lake 
  level. 
  It 
  may 
  be 
  cut 
  down 
  a 
  little, 
  but 
  only 
  a 
  little, 
  lower 
  

   than 
  the 
  lake 
  level 
  and 
  covered 
  with 
  the 
  delta 
  material. 
  

  

  The 
  evidence 
  at 
  Payne's 
  creek, 
  near 
  Aurora, 
  is 
  still 
  more 
  strik- 
  

   ing. 
  The 
  lower 
  part 
  of 
  the 
  stream 
  bed 
  is 
  entirely 
  of 
  loose 
  material 
  — 
  

   no 
  rock 
  being 
  visible 
  for 
  a 
  long 
  distance 
  up 
  the 
  creek 
  — 
  showing 
  

   that 
  the 
  preglacial 
  stream 
  cut 
  its 
  valley 
  below 
  the 
  present 
  sur- 
  

   face 
  of 
  the 
  lake. 
  Just 
  how 
  far 
  down 
  the 
  rock 
  bottom 
  is, 
  can 
  not 
  be 
  

   accurately 
  known. 
  There 
  is 
  an 
  old 
  sulphur 
  spring 
  just 
  here, 
  drilled, 
  

   I 
  am 
  told, 
  by 
  a 
  Syracuse 
  firm, 
  but 
  nobody 
  seems 
  to 
  know 
  where 
  

   the 
  driller's 
  notes 
  are 
  If 
  they 
  could 
  be 
  found 
  they 
  would 
  decide 
  

   this 
  point. 
  

  

  The 
  preglacial 
  rock 
  wall 
  of 
  this 
  stream 
  rises 
  100 
  yards 
  south 
  at 
  a 
  

   gentle 
  slope. 
  Knowing 
  the 
  general 
  form 
  of 
  such 
  valleys 
  in 
  this 
  

   region, 
  we 
  can 
  draw 
  a 
  profile 
  to 
  scale, 
  and 
  by 
  the 
  curve 
  of 
  this 
  slope 
  

   we 
  can 
  get 
  a 
  rough 
  estimate 
  of 
  the 
  depth 
  of 
  the 
  bottom 
  of 
  the 
  pre- 
  

   glacial 
  valley 
  below 
  the 
  lake 
  level. 
  By 
  this 
  method 
  I 
  conclude 
  that 
  

   the 
  rock 
  bottom 
  of 
  this 
  stream 
  is 
  at 
  least 
  45 
  feet 
  below 
  the 
  lake 
  sur- 
  

   face 
  and 
  not 
  more 
  than 
  65 
  feet. 
  (These 
  are 
  the 
  two 
  extreme 
  esti- 
  

   mates.) 
  Of 
  course 
  this 
  method 
  is 
  rough, 
  but 
  a 
  glance 
  at 
  the 
  ravine 
  

   and 
  its 
  surroundings 
  is 
  convincing 
  that 
  the 
  rock 
  bottom 
  is 
  a 
  number 
  

   of 
  feet 
  below 
  the 
  present 
  stream 
  bed 
  at 
  its 
  mouth. 
  

  

  We 
  have 
  noticed 
  that 
  the 
  hills 
  enclosing 
  the 
  lake 
  valley 
  diverge 
  

   gradually 
  northward 
  — 
  from 
  being 
  half 
  a 
  mile 
  apart 
  at 
  Spencer 
  sum- 
  

   mit 
  to 
  some 
  eight 
  or 
  10 
  miles 
  at 
  Cayuga 
  — 
  a 
  distance 
  of 
  60 
  miles 
  ; 
  

   that 
  these 
  hills 
  also 
  decrease 
  in 
  height 
  northward 
  ; 
  we 
  have 
  found 
  

   three 
  preglacial 
  valleys 
  whose 
  bottoms 
  become 
  lower, 
  respectively, 
  

   toward 
  the 
  north. 
  The 
  only 
  logical 
  conclusion 
  therefore, 
  is 
  that 
  the 
  

   lake 
  lives 
  in 
  the 
  valley 
  of 
  a 
  preglacial 
  stream. 
  Fig. 
  6 
  will 
  illustrate 
  

   this 
  evidence. 
  

  

  a 
  Bull, 
  ereol. 
  soc. 
  Am. 
  1894. 
  v. 
  5, 
  PI. 
  14 
  

  

  