﻿102 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  The 
  linear 
  type 
  of 
  lake 
  is 
  by 
  far 
  the 
  most 
  common,, 
  this 
  being 
  pre- 
  

   eminently 
  true 
  of 
  the 
  Finger 
  lakes 
  and 
  to 
  a 
  large 
  extent 
  of 
  the 
  

   Adirondacks. 
  It 
  is 
  well 
  known 
  that 
  most 
  of 
  the 
  larger 
  lakes, 
  espe- 
  

   cially 
  those 
  of 
  the 
  linear 
  type, 
  occupy 
  portions 
  of 
  preglacial 
  stream 
  

   channels. 
  All 
  the 
  existing 
  lakes 
  are 
  due, 
  either 
  directly 
  or 
  indi- 
  

   rectly, 
  to 
  glacial 
  action, 
  and 
  among 
  the 
  ways 
  by 
  which 
  such 
  bodies 
  

   of 
  water 
  were 
  formed 
  are 
  these: 
  by 
  building 
  dams 
  of 
  glacial 
  drift 
  

   across 
  old 
  river 
  channels 
  ; 
  by 
  ice 
  erosion 
  ; 
  and 
  by 
  the 
  filling 
  of 
  the 
  

   numerous 
  depressions 
  which 
  were 
  formed 
  by 
  irregular 
  deposition 
  

   of 
  the 
  drift 
  (kettle 
  holes, 
  etc.). 
  Hundreds 
  of 
  small 
  lakes, 
  often 
  

  

  Fig. 
  34 
  The 
  time 
  of 
  the 
  Nipissing 
  Great 
  Lakes 
  and 
  Champlain 
  submer- 
  

   gence. 
  The 
  shaded 
  area 
  on 
  the 
  east 
  was 
  covered 
  by 
  sea 
  water. 
  

  

  After 
  Taylor 
  

  

  not 
  more 
  than 
  mere 
  ponds 
  in 
  size, 
  belong 
  to 
  the 
  last 
  named 
  type, 
  

   while 
  most 
  of 
  the 
  large 
  lakes 
  are 
  due 
  chiefly 
  to 
  the 
  existence 
  of 
  drift 
  

   dams. 
  

  

  Much 
  has 
  been 
  written 
  concerning 
  the 
  origin 
  of 
  the 
  Finger 
  lakes, 
  

   and 
  only 
  the 
  briefest 
  summary 
  will 
  here 
  be 
  given. 
  All 
  are 
  agreed 
  

   that 
  the 
  lakes 
  of 
  this 
  remarkable 
  group 
  occupy 
  preglacial 
  valleys, 
  

   most 
  of 
  which, 
  at 
  least, 
  contained 
  north-flowing 
  streams. 
  These 
  

   lakes 
  have 
  dams 
  of 
  glacial 
  drift 
  across 
  their 
  lower 
  (north) 
  ends, 
  

   and 
  the 
  dams 
  have 
  largely 
  contributed 
  to 
  the 
  formation 
  of 
  the 
  lakes, 
  

   being 
  in 
  some 
  cases 
  perhaps 
  the 
  sole 
  cause 
  of 
  the 
  lakes. 
  In 
  the 
  

  

  