﻿644 
  • 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  the 
  one 
  time 
  presence 
  of 
  an 
  ice 
  remnant. 
  The 
  margins 
  of 
  the 
  

   •depression 
  also 
  are 
  contoured 
  as 
  if 
  by 
  deposition 
  against 
  a 
  mass 
  of 
  

   ice. 
  It 
  is 
  precisely 
  in 
  this 
  portion 
  of 
  the 
  ice 
  front 
  that 
  the 
  crest 
  of 
  

   the 
  moraine 
  bears 
  indications 
  of 
  having 
  been 
  overridden 
  by 
  the 
  ice 
  

   (p. 
  638). 
  

  

  The 
  transmorainal 
  water 
  courses 
  are 
  best 
  studied 
  at 
  Roslyn. 
  At 
  

   this 
  point 
  the 
  glacial 
  stream 
  excavated 
  a 
  trench 
  nearly 
  40 
  feet 
  deep 
  

   in 
  the 
  gravels 
  immediately 
  adjacent 
  to 
  the 
  moraine 
  on 
  the 
  south, 
  

   forming 
  well 
  defined 
  terraces 
  fairly 
  well 
  brought 
  out 
  by 
  the 
  con- 
  

   tours 
  on 
  the 
  map. 
  About 
  a 
  mile 
  below 
  Roslyn 
  this 
  crease 
  turns 
  

   sharply 
  eastward 
  for 
  half 
  a 
  mile, 
  then 
  straightens 
  out 
  and 
  continues 
  

   southward 
  by 
  Albertson, 
  to 
  the 
  east 
  of 
  East 
  Williston 
  and 
  thence 
  to 
  

   the 
  sea. 
  

  

  The 
  frontal 
  plain 
  near 
  Creedmoor 
  exhibits 
  no 
  marked 
  trace 
  of 
  a 
  

   crease, 
  and 
  many 
  creases 
  which 
  are 
  distinct 
  on 
  the 
  outer 
  southern 
  

   margin 
  of 
  the 
  outwash 
  plain 
  become 
  faint 
  and 
  practically 
  disappear 
  

   as 
  surface 
  features 
  nearer 
  the 
  moraine. 
  This 
  fading 
  of 
  creases 
  

   would 
  be 
  caused 
  by 
  the 
  wandering 
  of 
  streams 
  over 
  the 
  surface, 
  

   spreading 
  gravel 
  and 
  sand, 
  with 
  the 
  aggradation 
  or 
  building 
  up 
  of 
  

   the 
  plain 
  by 
  the 
  streams 
  near 
  the 
  ice 
  front 
  so 
  long 
  as 
  they 
  were 
  

   overloaded 
  with 
  debris. 
  

  

  The 
  creases 
  on 
  the 
  eastern 
  part 
  of 
  the 
  Hempstead 
  quadrangle 
  are 
  

   deflected 
  southwestward 
  into 
  the 
  Jamaica 
  bay 
  depression. 
  East 
  of 
  

   that 
  region, 
  the 
  streams 
  flow 
  generally 
  southward, 
  the 
  numerous 
  

   creases 
  marked 
  by 
  the 
  100 
  foot 
  contour 
  line, 
  for 
  instance, 
  gathering 
  

   southward 
  into 
  six 
  or 
  seven 
  drainage 
  channels 
  through 
  which 
  small 
  

   streams 
  now 
  drain 
  the 
  water 
  from 
  the 
  plain. 
  

  

  Outwash 
  plain. 
  The 
  outwash 
  plain 
  is 
  evidently 
  more 
  complex 
  

   in 
  its 
  origin 
  that 
  its 
  mere 
  surface 
  would 
  indicate. 
  The 
  disap- 
  

   pearance 
  of 
  the 
  older 
  Pleistocene 
  gravels 
  beneath 
  the 
  moraine 
  on 
  

   the 
  north 
  at 
  about 
  200 
  feet 
  above 
  the 
  sea 
  has 
  already 
  been 
  noted. 
  

   Just 
  as 
  the 
  level 
  of 
  these 
  deposits 
  falls 
  off 
  on 
  the 
  north 
  side 
  of 
  the 
  

   moraine 
  to 
  the 
  westward, 
  so 
  does 
  the 
  hight 
  of 
  the 
  outwash 
  plain, 
  

   and, 
  for 
  that 
  matter, 
  that 
  of 
  the 
  main 
  moraine 
  itself. 
  There 
  is 
  good 
  

   reason 
  for 
  holding 
  therefore 
  that 
  the 
  so-called 
  Columbia 
  deposits 
  

   extend 
  south 
  of 
  the 
  moraine 
  and 
  presumably 
  imderlie 
  the 
  outwash 
  

   plain, 
  if 
  they 
  do 
  not 
  actually 
  form 
  here 
  and 
  there 
  surface 
  exposures. 
  

  

  