﻿PLEISTOCENE 
  GEOLOGY 
  OF 
  NASSAU 
  CO. 
  AND 
  BOROUGH 
  OF 
  QUEENS 
  635 
  

  

  the 
  surface 
  of 
  the 
  formation 
  north 
  of 
  the 
  moraine 
  is 
  carved 
  into 
  

   valleys 
  and 
  deep 
  reentrants 
  of 
  the 
  coast 
  line, 
  depressions 
  the 
  main 
  

   features 
  of 
  which 
  are 
  consonant 
  neither 
  with 
  the 
  southward 
  move- 
  

   ment 
  of 
  ice 
  over 
  the 
  area 
  nor 
  the 
  erosive 
  work 
  of 
  subglacial 
  streams 
  

   discharging 
  across 
  them 
  at 
  the 
  ice 
  front. 
  That 
  these 
  valleys 
  ante- 
  

   date 
  the 
  last 
  ice 
  advance 
  appears 
  to 
  be 
  shown 
  in 
  that 
  all 
  of 
  them 
  are 
  

   more 
  or 
  less 
  encumbered 
  by 
  morainal 
  materials. 
  

  

  As 
  typical 
  examples 
  of 
  these 
  valleys, 
  that 
  entering 
  into 
  Manhas- 
  

   set 
  bay 
  at 
  Glen 
  Cove, 
  as 
  well 
  as 
  that 
  in 
  whose 
  lower 
  extension 
  Mill 
  

   Neck 
  creek 
  flows, 
  may 
  be 
  taken. 
  The 
  Glen 
  Cove 
  valley 
  heads 
  at 
  

   the 
  inner 
  base 
  of 
  the 
  moraine 
  near 
  a 
  very 
  well 
  marked 
  pass 
  at 
  the 
  

   eastern 
  base 
  of 
  Harbor 
  hill, 
  a 
  passage 
  through 
  which 
  undoubtedly 
  

   subglacial 
  waters 
  escaped 
  when 
  the 
  ice 
  front 
  lay 
  against 
  the 
  moraine 
  

   and 
  at 
  a 
  time 
  when 
  it 
  must 
  be 
  admitted 
  subglacial 
  drainage 
  may 
  

   well 
  have 
  followed 
  the 
  course 
  of 
  this 
  valley 
  for 
  a 
  part 
  or 
  a 
  whole 
  of 
  

   its 
  course. 
  The 
  objections 
  to 
  accepting 
  the 
  valley, 
  however, 
  as 
  the 
  

   work 
  of 
  this 
  subglacial 
  stream, 
  aside 
  from 
  those 
  above 
  stated, 
  are 
  

   1) 
  the 
  graded 
  character 
  of 
  its 
  bed, 
  sloping 
  northward 
  toward 
  the 
  

   sea 
  as 
  if 
  made 
  by 
  a 
  normal 
  stream 
  like 
  that 
  now 
  flowing 
  in 
  it, 
  

   though 
  the 
  existing 
  stream 
  evidently 
  flows 
  in 
  a 
  valley 
  which 
  it 
  

   found 
  encumbered 
  by 
  more 
  or 
  less 
  glacial 
  drift 
  ; 
  2) 
  the 
  tributary 
  

   vales 
  evidently 
  cut 
  by 
  running 
  water 
  as 
  in 
  normal 
  open 
  air 
  streams 
  ; 
  

   3) 
  the 
  course 
  of 
  the 
  stream 
  at 
  Glen 
  Cove, 
  east 
  and 
  west, 
  in 
  a 
  direc- 
  

   tion 
  contrary 
  to 
  ice 
  movement 
  in 
  this 
  locality. 
  The 
  digitation 
  is 
  

   even 
  more 
  pronounced 
  in 
  the 
  case 
  of 
  the 
  Mill 
  I^eck 
  creek 
  valley 
  

   just 
  south 
  of 
  the 
  ponds. 
  The 
  upper 
  part 
  of 
  the 
  valley 
  above 
  the 
  

   100 
  foot 
  contour 
  is 
  also 
  walled 
  in 
  by 
  glacial 
  deposits 
  later 
  than 
  the 
  

   Columbia 
  in 
  which 
  it 
  is 
  cut. 
  Like 
  considerations 
  hold 
  in 
  regard 
  to 
  

   the 
  deep 
  valleys 
  which 
  extend 
  from 
  Oyster 
  Bay 
  village 
  toward 
  

   East 
  JSTorwich. 
  The 
  Mill 
  IN^eck 
  creek 
  depression 
  continues 
  below 
  

   sealevel, 
  and, 
  branching 
  south 
  of 
  Oak 
  neck, 
  separates 
  that 
  island 
  — 
  

   an 
  island 
  except 
  for 
  the 
  barrier 
  beach 
  tying 
  it 
  to 
  the 
  land 
  on 
  the 
  

   west 
  — 
  from 
  Mill 
  IS'eck. 
  It 
  is 
  evident 
  that 
  there 
  has 
  been 
  developed 
  

   a 
  marked 
  dissection 
  of 
  the 
  Columbia, 
  and 
  that 
  this 
  dissection 
  on 
  north 
  

   and 
  south 
  as 
  well 
  as 
  on 
  east 
  and 
  west 
  lines 
  is 
  increasingly 
  severe 
  

   toward 
  the 
  northern 
  coast, 
  as 
  in 
  the 
  normal 
  degradation 
  of 
  an 
  area 
  

   of 
  incoherent 
  materials 
  marginal 
  to 
  a 
  depression 
  such 
  as 
  that 
  of 
  

  

  