﻿650 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  the 
  moraine. 
  So 
  far 
  as 
  can 
  be 
  seen, 
  such 
  a 
  body 
  of 
  water 
  must 
  

   have 
  been 
  the 
  sea, 
  and 
  it 
  would 
  be 
  warrantable 
  to 
  suppose 
  that 
  the 
  

   land 
  stood 
  80 
  feet 
  lower 
  than 
  now 
  with 
  reference 
  to 
  the 
  ocean. 
  

  

  Jamaica 
  bay 
  depression 
  

  

  The 
  possibility 
  of 
  such 
  deformation 
  of 
  the 
  frontal 
  plain 
  since 
  

   glacial 
  times 
  as 
  would 
  produce 
  the 
  present 
  departure 
  from 
  the 
  80 
  

   foot 
  level 
  along 
  the 
  northern 
  margin 
  is 
  negatived 
  by 
  the 
  peculiar 
  

   depression 
  known 
  as 
  Jamaica 
  bay, 
  whose 
  origin 
  it 
  is 
  now 
  necessary 
  

   to 
  consider 
  before 
  arriving 
  at 
  a 
  conclusion 
  concerning 
  the 
  submer- 
  

   gence 
  or 
  non-submergence 
  of 
  the 
  island 
  at 
  the 
  time 
  of 
  the 
  Port 
  

   Washington 
  stage 
  of 
  ice 
  retreat. 
  

  

  The 
  semicircular 
  area 
  of 
  marshes 
  and 
  salt 
  creeks 
  forming 
  Jamaica 
  

   bay 
  outlines 
  a 
  remarkable 
  depression 
  in 
  the 
  outwash 
  plain. 
  The 
  

   moraine 
  immediately 
  back 
  of 
  it 
  is 
  quite 
  as 
  well 
  developed 
  as 
  for 
  

   some 
  distance 
  east 
  and 
  west 
  of 
  it, 
  nor 
  is 
  the 
  crest 
  of 
  the 
  moraine 
  

   perceptibly 
  lower 
  at 
  this 
  point, 
  where 
  there 
  appears 
  to 
  be 
  a 
  lack 
  

   of 
  development 
  of 
  the 
  plain. 
  The 
  moraine 
  shows 
  therefore 
  no 
  

   signs 
  of 
  having 
  been 
  depressed 
  at 
  this 
  point, 
  and 
  was 
  formed 
  prob- 
  

   ably 
  later 
  than 
  the 
  dejDression 
  referred 
  to. 
  

  

  That 
  this 
  depression 
  in 
  the 
  plain 
  is 
  a 
  feature 
  dating 
  from 
  early 
  

   glacial 
  times 
  and 
  an 
  original 
  feature 
  in 
  the 
  growth 
  of 
  the 
  plain 
  is 
  

   also 
  shown 
  by 
  the 
  behavior 
  of 
  the 
  creases 
  or 
  drainage 
  channels 
  

   which 
  lead 
  into 
  the 
  bay 
  : 
  these 
  creases 
  converge 
  on 
  all 
  sides 
  toward 
  

   the 
  depression, 
  showing 
  that 
  the 
  slopes 
  of 
  the 
  plain 
  were 
  then 
  as 
  

   now 
  toward 
  this 
  relatively 
  unfilled 
  area. 
  It 
  follows 
  therefore 
  that 
  

   the 
  plain 
  has 
  not 
  necessarily 
  been 
  deformed 
  since 
  glacial 
  times, 
  and 
  

   that 
  the 
  rising 
  and 
  falling 
  of 
  the 
  inner 
  line 
  of 
  contact 
  of 
  the 
  plain 
  

   with 
  the 
  moraine 
  is 
  an 
  original 
  constructional 
  characteristic 
  of 
  the 
  

   deposits. 
  If 
  this 
  reasoning 
  be 
  correct, 
  then 
  the 
  local 
  coincidence 
  in 
  

   level 
  of 
  the 
  inner 
  margin 
  of 
  the 
  plain 
  with 
  the 
  level 
  of 
  the 
  Port 
  

   Washington 
  delta 
  is 
  not 
  due 
  to 
  the 
  control 
  of 
  a 
  water 
  level 
  common 
  

   to 
  both 
  areas. 
  

  

  Moreover 
  there 
  is 
  reason 
  to 
  believe 
  that 
  the 
  frontal 
  plain 
  was 
  

   mainly 
  developed 
  when 
  the 
  ice 
  lay 
  along 
  the 
  inner 
  moraine 
  pre- 
  

   vious 
  to 
  the 
  Port 
  Washington 
  stage, 
  and, 
  as 
  will 
  shortly 
  be 
  stated, 
  

   that 
  the 
  Port 
  Washington 
  delta 
  was 
  deposited 
  later 
  in 
  a 
  temporary 
  

   lake 
  confined 
  between 
  the 
  moraine 
  and 
  the 
  retreating 
  ice 
  front. 
  

  

  