﻿JO 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  taining 
  a 
  pond) 
  below 
  the 
  level 
  of 
  the 
  plain. 
  Such 
  depressions 
  

   are 
  thought 
  to 
  be 
  due 
  either 
  to 
  unequal 
  deposition 
  of 
  the 
  delta 
  

   material 
  or 
  the 
  presence 
  of 
  large 
  buried 
  blocks 
  of 
  ice 
  which 
  on 
  

   melting 
  would 
  leave 
  the 
  depressions. 
  The 
  contact 
  of 
  the 
  lake 
  sur- 
  

   face, 
  at 
  its 
  height, 
  with 
  the 
  surrounding 
  land 
  is 
  quite 
  accurately 
  

   indicated 
  by 
  the 
  760 
  foot 
  contour 
  line 
  but, 
  because 
  of 
  postglacial 
  

   changes 
  of 
  level, 
  the 
  actual 
  altitude 
  of 
  the 
  lake 
  above 
  the 
  sea 
  is 
  not 
  

   known. 
  On 
  a 
  line 
  passing 
  east 
  and 
  west 
  through 
  Warrensburg 
  

   the 
  main 
  body 
  of 
  water 
  showed 
  its 
  greatest 
  width 
  of 
  about 
  3 
  miles. 
  

   Clearly 
  defined 
  sand 
  terraces, 
  the 
  highest 
  of 
  which 
  always 
  rise 
  to 
  

   the 
  760 
  or 
  780 
  foot 
  contour 
  lines, 
  prove 
  that 
  important 
  arms 
  of 
  

   the 
  lake 
  extended 
  fully 
  9 
  miles 
  up 
  the 
  Schroon 
  river 
  valley 
  above 
  

   Warrensburg; 
  nearly 
  4 
  miles 
  up 
  the 
  Hudson 
  valley 
  above 
  the 
  

   mouth 
  of 
  the 
  Schroon 
  ; 
  and 
  at 
  least 
  2 
  miles 
  down 
  the 
  Hudson 
  from 
  

   the 
  mouth 
  of 
  the 
  Schroon. 
  The 
  altitudes 
  of 
  these 
  sand 
  terraces 
  

   gradually 
  increase 
  slightly 
  toward 
  the 
  north 
  because 
  of 
  the 
  post- 
  

   glacial 
  warping 
  of 
  the 
  region 
  as 
  explained 
  on 
  page 
  66. 
  

  

  In 
  the 
  vicinity 
  of 
  Warrensburg, 
  and 
  especially 
  along 
  the 
  Schroon 
  

   river, 
  the 
  lake 
  deposits, 
  though 
  deeply 
  trenched, 
  have 
  seldom 
  been 
  

   cut 
  through 
  to 
  the 
  underlying 
  rock. 
  As 
  a 
  result 
  of 
  the 
  meandering 
  

   of 
  the 
  Hudson 
  and 
  Schroon 
  rivers, 
  during 
  the 
  process 
  of 
  trench- 
  

   ing 
  the 
  old 
  lake 
  deposits, 
  fine 
  terraces 
  have 
  been 
  developed. 
  Such 
  

   terraces 
  are 
  particularly 
  well 
  shown 
  between 
  Potter, 
  Heath, 
  and 
  

   Moon 
  mountains 
  where 
  they 
  are 
  at 
  two 
  or 
  three 
  different 
  levels 
  

   and 
  from 
  a 
  quarter 
  to 
  a 
  half 
  mile 
  back 
  from 
  the 
  river 
  as 
  the 
  

   contour 
  lines 
  partly 
  indicate. 
  

  

  The 
  cause 
  of 
  the 
  standing 
  water 
  was 
  a 
  blockade, 
  probably 
  of 
  

   glacial 
  drift, 
  in 
  the 
  Stony 
  Creek 
  gorge 
  (Luzerne 
  sheet). 
  

  

  Glacial 
  Lake 
  Pottersville. 
  This 
  lake, 
  here 
  described 
  for 
  the 
  

   first 
  time, 
  must 
  take 
  rank 
  as 
  one 
  of 
  the 
  largest 
  and 
  most 
  interest- 
  

   ing 
  extinct 
  glacial 
  lakes 
  yet 
  recognized 
  in 
  the 
  Adirondacks. 
  It 
  is 
  

   so 
  named 
  because 
  the 
  best 
  example 
  of 
  sand 
  flat 
  delta 
  deposit 
  

   formed 
  in 
  the 
  lake 
  lies 
  in 
  the 
  vicinity 
  of 
  Pottersville. 
  This 
  sand 
  

   plain 
  covers 
  fully 
  a 
  square 
  mile 
  at 
  an 
  altitude 
  of 
  about 
  800 
  feet,, 
  

   though 
  the 
  highest 
  waterlaid 
  sands 
  and 
  gravels 
  occur 
  from 
  one- 
  

   third 
  to 
  two-thirds 
  of 
  a 
  mile 
  northwest 
  of 
  the 
  village 
  and 
  at 
  an 
  

   altitude 
  of 
  nearly 
  900 
  feet. 
  This 
  material 
  was 
  all 
  formed 
  as 
  a 
  

   delta 
  deposit 
  by 
  Trout 
  brook 
  in 
  a 
  body 
  of 
  water 
  which 
  stood 
  at 
  

   a 
  level 
  corresponding 
  approximately 
  to 
  the 
  present 
  900 
  foot 
  con- 
  

   tour 
  line 
  at 
  Pottersville. 
  This 
  body 
  of 
  water 
  was 
  Lake 
  Potters- 
  

   ville 
  of 
  which 
  Schroon 
  lake 
  is 
  only 
  a 
  shrunken 
  remnant. 
  The 
  

  

  