﻿656 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  makes 
  it 
  highly 
  probable 
  that 
  for 
  a 
  time 
  Hempstead 
  harbor 
  was 
  

   the 
  site 
  of 
  a 
  small 
  glacial 
  lake, 
  at 
  first 
  discharging 
  at 
  the 
  120 
  foot 
  

   level 
  at 
  Eosljn, 
  and 
  later 
  by 
  the 
  80 
  foot 
  channel 
  into 
  the 
  Manhasset 
  

   water 
  body. 
  It 
  now 
  remains 
  to 
  determine 
  whether 
  tlie 
  high 
  level 
  of 
  

   water 
  in 
  Manhasset 
  bay 
  was 
  then 
  at 
  sealevel 
  or 
  whether 
  it 
  too 
  w^as 
  

   held 
  up 
  by 
  a 
  glacial 
  barrier. 
  

  

  South 
  of 
  Manhasset 
  is 
  a 
  col 
  in 
  the 
  moraine, 
  at 
  an 
  elevation 
  of 
  

   about 
  175 
  feet, 
  much 
  higher 
  than 
  many 
  cols 
  separating 
  the 
  bay 
  from 
  

   lower 
  passes 
  through 
  the 
  moraine 
  in 
  the 
  country 
  on 
  the 
  east 
  of 
  the 
  

   bay. 
  It 
  is 
  evident 
  tliat 
  this 
  col, 
  which 
  lies 
  just 
  east 
  of 
  Lake 
  Sur- 
  

   prise, 
  could 
  not 
  have 
  been 
  used 
  as 
  an 
  outlet 
  for 
  the 
  water 
  confined 
  

   in 
  Manhasset 
  bay 
  after 
  the 
  ice 
  front 
  had 
  retired 
  as 
  far 
  north 
  as 
  Port 
  

   "Washington, 
  for 
  the 
  water 
  level 
  had 
  then 
  fallen 
  to 
  80 
  feet, 
  as 
  wit- 
  

   nessed 
  by 
  the 
  delta 
  at 
  that 
  locality. 
  

  

  West 
  of 
  Manhasset 
  bay, 
  most 
  of 
  the 
  region 
  north 
  of 
  the 
  moraine 
  

   fails 
  to 
  attain 
  the 
  100 
  foot 
  level. 
  The 
  moraine 
  itself 
  presents 
  a 
  con- 
  

   tinuous 
  barrier 
  rising 
  above 
  the 
  80 
  foot 
  contour 
  line 
  at 
  all 
  points 
  till 
  

   the 
  vicinity 
  of 
  Maple 
  Grove 
  is 
  reached. 
  Between 
  this 
  locality 
  and 
  

   Prospect 
  park 
  in 
  Brooklyn, 
  there 
  are 
  eight 
  or 
  nine 
  low, 
  troughlike 
  

   passes 
  across 
  the 
  crest 
  of 
  the 
  moraine, 
  which 
  might 
  have 
  served 
  for 
  

   the 
  overflow 
  of 
  water 
  held 
  in 
  on 
  the 
  north 
  between 
  the 
  moraine 
  and 
  

   the 
  retreating 
  ice 
  front 
  as 
  late 
  as 
  the 
  Port 
  Washington 
  stage, 
  w^hile 
  

   the 
  ice, 
  on 
  account 
  of 
  its 
  greater 
  activity 
  near 
  the 
  axis 
  of 
  the 
  Hud- 
  

   son 
  lobe, 
  maintained 
  its 
  position 
  close 
  to 
  the 
  moraine 
  in 
  the 
  vicinity 
  

   of 
  Brooklyn, 
  at 
  least 
  depassing 
  the 
  80 
  foot 
  contour 
  line 
  on 
  the 
  back 
  

   of 
  the 
  moraine 
  so 
  as 
  effectually 
  to 
  prevent 
  discharge 
  by 
  a 
  lower 
  

   level 
  into 
  New 
  York 
  bay 
  north 
  of 
  the 
  Narrows. 
  

  

  These 
  troughs 
  across 
  the 
  moraine 
  are 
  singularly 
  uniform 
  in 
  level. 
  

   In 
  all 
  those 
  enumerated 
  their 
  bottoms 
  lie 
  according 
  to 
  the 
  govern- 
  

   ment 
  survey 
  between 
  the 
  100 
  foot 
  and 
  the 
  80 
  foot 
  contour 
  lines. 
  

   Some 
  of 
  them 
  are 
  clearly 
  inosculating 
  kettle-holes, 
  marking 
  the 
  site 
  

   of 
  melting 
  masses 
  of 
  the 
  ice. 
  From 
  some 
  of 
  them, 
  drainage 
  creases 
  

   can 
  be 
  traced 
  out 
  over 
  the 
  frontal 
  plain. 
  They 
  are 
  best 
  developed 
  

   in 
  line 
  with 
  the 
  bays 
  aud 
  depressions 
  on 
  the 
  north 
  side 
  of 
  the 
  

   moraine, 
  and 
  hence 
  v/ere 
  probably 
  the 
  paths 
  of 
  subglacial 
  streams, 
  

   as 
  in 
  the 
  case 
  of 
  the 
  passes 
  on 
  the 
  Oyster 
  Bay 
  quadrangle. 
  They 
  

   are 
  however 
  not 
  unique 
  in 
  this 
  portion 
  of 
  the 
  moraine. 
  There 
  are 
  

  

  