﻿rTO 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  entering 
  the 
  lake, 
  with 
  only 
  13 
  of 
  this 
  number 
  entering 
  the 
  northern 
  

   third 
  of 
  the 
  basin. 
  The 
  majority 
  of 
  the 
  total 
  number 
  of 
  tributaries, 
  

   however, 
  are 
  very 
  small 
  and 
  distinctly 
  post-glacial 
  throughout 
  

   their 
  courses, 
  but 
  all 
  of 
  the 
  larger 
  ones 
  which 
  have 
  been 
  traced 
  

   as 
  preglacial, 
  enter 
  the 
  southern 
  half 
  of 
  the 
  basin, 
  and 
  not 
  one 
  can 
  

   be 
  shown 
  to 
  have 
  entered 
  near 
  the 
  outlet 
  part 
  of 
  the 
  valley. 
  This 
  

   is 
  entirely 
  in 
  harmony 
  with 
  a 
  normally 
  developed 
  north 
  flowing 
  

   stream, 
  

  

  Tlie 
  evidence 
  for 
  north 
  versus 
  south 
  flow 
  for 
  the 
  preglacial 
  

   Cayuga 
  and 
  Seneca 
  valleys 
  can 
  be 
  summed 
  up 
  in 
  the 
  following 
  brief 
  

   statement; 
  namely, 
  that 
  the 
  entire 
  topography 
  is 
  directly 
  opposed 
  to 
  

   and 
  inconsistent 
  with 
  a 
  south 
  flow 
  for 
  these 
  streams. 
  The 
  divides 
  

   have 
  further 
  suffered 
  from 
  the 
  effects 
  of 
  glaciation, 
  just 
  how 
  much, 
  

   is 
  difficult 
  to 
  state, 
  but 
  the 
  evidence 
  seems 
  not 
  to 
  favor 
  the 
  hypothe- 
  

   ses 
  of 
  any 
  very 
  extensive 
  migration 
  from 
  this 
  cause. 
  

  

  Classification 
  of 
  lacustrine 
  deposits 
  

  

  The 
  deposits 
  in 
  glacial 
  lakes 
  away 
  from 
  the 
  immediate 
  shore 
  line 
  

   are 
  capable 
  of 
  differentiation 
  and 
  classification 
  into 
  two 
  distinct 
  

   types. 
  In 
  many 
  instances, 
  however, 
  these 
  cannot, 
  with 
  any 
  degree 
  

   of 
  certainty, 
  be 
  differentiated 
  from 
  each 
  other. 
  

  

  Berg 
  deposits. 
  No 
  portion 
  of 
  the 
  material 
  found 
  within 
  the 
  

   lacustrine 
  limits 
  has 
  been 
  definitely 
  traced 
  to 
  berg 
  action. 
  Other 
  

   things 
  being 
  equal, 
  the 
  lake 
  depth 
  during 
  some 
  of 
  the 
  higher 
  levels 
  

   was 
  sufficient 
  to 
  float 
  bergs 
  of 
  fair 
  dimensions, 
  and 
  it 
  is 
  not 
  unlikely 
  

   that 
  some 
  of 
  the 
  deposits 
  are 
  due 
  to 
  this 
  cause. 
  There 
  seems 
  to 
  be 
  

   better 
  grounds 
  for 
  ascribing 
  to 
  this 
  agency 
  some 
  of 
  the 
  boulders 
  dis- 
  

   tributed 
  over 
  the 
  valley 
  bottoms, 
  rather 
  than 
  any 
  of 
  the 
  finer 
  material, 
  

   but 
  even 
  in 
  this 
  case, 
  nothing 
  definite 
  can 
  be 
  said, 
  since 
  they 
  might 
  

   very 
  well 
  have 
  resulted 
  directly 
  from 
  the 
  ice. 
  Unless 
  the 
  deposits 
  

   were 
  conspicuously 
  marked 
  it 
  would 
  be 
  exceedingly 
  difficult 
  to 
  

   locate 
  them 
  over 
  the 
  lake 
  floor 
  in 
  the 
  respective 
  valleys, 
  and 
  thereby 
  

   differentiate 
  them 
  from 
  other 
  deposits, 
  inasmuch 
  as 
  the 
  entire 
  lake 
  

   extension 
  lies 
  wholly 
  within 
  the 
  glacial 
  limits, 
  and 
  the 
  true 
  glacial 
  

   drift 
  is 
  very 
  heavy 
  and 
  extensive 
  throughout. 
  

  

  Lacustrine 
  clays 
  and 
  silts. 
  In 
  some 
  parts 
  of 
  the 
  valleys, 
  nota- 
  

   bly 
  in 
  the 
  southern 
  portions, 
  clays 
  and 
  silts 
  resulting 
  in 
  all 
  proba- 
  

   bility 
  from 
  lake 
  action, 
  can, 
  I 
  believe, 
  be 
  differentiated. 
  They 
  by 
  

  

  