﻿114 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  In 
  the 
  southern 
  Finger 
  lakes 
  region 
  of 
  south-central 
  New 
  York 
  

   there 
  are 
  numerous 
  postglacial 
  gorges, 
  a 
  few 
  of 
  the 
  best 
  known 
  

   ones 
  being: 
  Watkins 
  and 
  Havana 
  glens 
  near 
  the 
  southern 
  end 
  of 
  

   Seneca 
  lake, 
  Taughannock 
  gorge 
  on 
  the 
  west 
  side 
  of 
  Cayuga 
  lake 
  

   and 
  in 
  northern 
  Tompkins 
  county, 
  and 
  the 
  gorges 
  of 
  Butternut 
  

   (Enfield), 
  Fall, 
  Six 
  Mile, 
  and 
  Buttermilk 
  creeks 
  in 
  the 
  vicinity 
  of 
  

   Ithaca. 
  These 
  gorges 
  all 
  contain 
  waterfalls 
  and 
  have 
  been 
  cut 
  

   into 
  Devonic 
  shales 
  or 
  sandy 
  shales 
  by 
  streams 
  which 
  have 
  been 
  

   either 
  partly 
  or 
  wholly 
  diverted 
  from 
  their 
  preglacial 
  courses 
  due 
  

   to 
  heavy 
  drift 
  filling. 
  In 
  some 
  cases, 
  as 
  at 
  Watkins 
  and 
  Taughan- 
  

   nock, 
  the 
  main 
  north-south 
  Seneca 
  and 
  Cayuga 
  valleys 
  were 
  scoured 
  

   and 
  somewhat 
  deepened 
  by 
  ice 
  erosion, 
  while 
  in 
  all 
  cases 
  the 
  tribu- 
  

   tary 
  channels 
  were 
  heavily 
  drift 
  filled, 
  thus 
  accounting 
  for 
  the 
  

   frequent 
  postglacial 
  diversion 
  of 
  these 
  streams 
  which 
  were 
  forced 
  

   to 
  cut 
  new 
  channels 
  into 
  the 
  steep 
  slopes 
  facing 
  the 
  main 
  valleys. 
  

  

  Watkins 
  glen 
  is 
  several 
  miles 
  long, 
  often 
  very 
  narrow, 
  and 
  with 
  

   a 
  maximum 
  depth 
  of 
  over 
  300 
  feet. 
  Taughannock 
  gorge, 
  which 
  is 
  

   one 
  and 
  a 
  quarter 
  miles 
  long 
  and 
  with 
  greatest 
  depth 
  of 
  about 
  350 
  

   feet, 
  has 
  in 
  it 
  Taughannock 
  falls 
  whose 
  height 
  is 
  215 
  feet 
  and 
  which 
  

   takes 
  rank 
  as 
  the 
  highest 
  true 
  waterfall 
  in 
  New 
  York 
  State 
  (see 
  

   frontispiece). 
  Fall 
  creek 
  gorge, 
  on 
  the 
  north 
  side 
  of 
  Cornell 
  

   campus, 
  is 
  about 
  a 
  mile 
  long 
  and 
  with 
  greatest 
  depth 
  of 
  about 
  200 
  

   feet, 
  and 
  contains 
  Triphammer 
  and 
  Ithaca 
  falls. 
  The 
  Butternut 
  

   creek 
  (Enfield) 
  gorge 
  is 
  two 
  miles 
  long 
  and 
  with 
  maximum 
  depth 
  

   of 
  over 
  300 
  feet. 
  

  

  In 
  Chautauqua 
  county 
  there 
  are 
  numerous 
  gorges 
  or 
  so-called 
  

   gulfs 
  which 
  have 
  been 
  cut 
  through 
  the 
  steep 
  front 
  or 
  escarpment 
  

   of 
  the 
  western 
  border 
  of 
  the 
  Southwestern 
  plateau 
  province. 
  A 
  

   fine 
  example 
  is 
  the 
  gulf 
  south 
  of 
  Westfield, 
  which 
  is 
  several 
  miles 
  

   long 
  and 
  from 
  300 
  to 
  400 
  feet 
  deep. 
  These 
  are 
  also 
  postglacial 
  

   channels 
  which 
  have 
  been 
  worn 
  into 
  the 
  soft 
  Devonic 
  shales. 
  The 
  

   steepness 
  of 
  the 
  shale 
  escarpment 
  here, 
  as 
  in 
  the 
  case 
  of 
  Tug 
  hill, 
  

   was 
  more 
  than 
  likely 
  produced 
  by 
  ice 
  erosion, 
  while 
  the 
  preglacial 
  

   north-flowing 
  streams 
  had 
  their 
  channels 
  partially 
  or 
  completely 
  

   filled 
  with 
  glacial 
  debris 
  so 
  that 
  the 
  streams 
  now 
  often 
  flow 
  in 
  

   postglacial 
  channels. 
  The 
  conditions 
  are 
  here 
  very 
  similar 
  to 
  those 
  

   of 
  the 
  Finger 
  lakes 
  region 
  already 
  described. 
  

  

  Length 
  of 
  time 
  since 
  the 
  Ice 
  age. 
  Estimates 
  of 
  the 
  duration 
  

   of 
  the 
  glacial 
  epoch 
  by 
  the 
  most 
  able 
  students 
  of 
  the 
  subject 
  vary 
  

   from 
  500,000 
  to 
  1,500,000 
  years, 
  these 
  estimates 
  being 
  based 
  on 
  

   such 
  criteria 
  as 
  amount 
  of 
  erosion 
  and 
  weathering 
  of 
  the 
  earliest 
  

   till 
  sheets 
  (in 
  Mississippi 
  valley), 
  times 
  necessary 
  for 
  the 
  various 
  

  

  