﻿PLEISTOCENE 
  GEOLOGY 
  OF 
  NASSAU 
  CO. 
  AND 
  BOROUGH 
  OF 
  QUEENS 
  663 
  

  

  made 
  wlien 
  there 
  were 
  no 
  barrier 
  beaches, 
  are 
  beneath 
  the 
  present 
  

   sealeveh^ 
  

  

  Wherever 
  the 
  breadth 
  of 
  water 
  is 
  sufficient, 
  how^ever, 
  and 
  the 
  

   depth 
  too 
  great 
  to 
  permit 
  of 
  marsh 
  growth 
  the 
  bay 
  shores 
  are 
  now 
  

   being 
  cut 
  back 
  in 
  a 
  marked 
  manner 
  by 
  wave 
  action, 
  as 
  at 
  Cooper 
  

   bhiff. 
  

  

  Evidence 
  of 
  local 
  depression 
  of 
  the 
  shore 
  line 
  is 
  found 
  in 
  beds 
  of 
  

   peat 
  extending 
  outside 
  of 
  the 
  beach 
  below 
  low 
  tide 
  level. 
  Such 
  a 
  

   bed, 
  containing 
  a 
  flattened 
  log, 
  was 
  exposed 
  in 
  the 
  summer 
  of 
  1900 
  

   at 
  the 
  northeast 
  end 
  of 
  the 
  barrier 
  beach 
  uniting 
  Prospect 
  point 
  with 
  

   Sands 
  point. 
  Peat 
  was 
  also 
  exposed 
  on 
  the 
  front 
  of 
  the 
  beach 
  at 
  low 
  

   tide 
  half 
  a 
  mile 
  southeast 
  from 
  Prospect 
  point. 
  In 
  view, 
  however, 
  of 
  

   the 
  compressibility 
  of 
  the 
  original 
  swamp 
  deposits, 
  these 
  localities 
  

   can 
  hardly 
  be 
  regarded 
  as 
  proofs 
  of 
  a 
  general 
  sinking 
  of 
  the 
  

   island.^ 
  

  

  It 
  is 
  questionable 
  whether 
  even 
  measurable 
  evidence 
  of 
  a 
  slight 
  

   depression 
  of 
  the 
  shore 
  line 
  along 
  a 
  coast 
  of 
  incoherent 
  and 
  yielding 
  

   materials 
  such 
  as 
  the 
  clays 
  and 
  gravels 
  of 
  the 
  north 
  coast 
  of 
  Long 
  

   Island 
  may 
  be 
  taken 
  as 
  evidence 
  of 
  a 
  movement 
  of 
  the 
  continent. 
  

   There 
  is 
  a 
  slow 
  movement 
  of 
  the 
  loose 
  materials 
  toward 
  the 
  shore 
  in 
  

   rnany 
  high 
  bluffs. 
  At 
  Ragged 
  Land 
  point 
  east 
  of 
  Northport 
  harbor 
  

   this 
  movement 
  in 
  clays 
  has 
  developed 
  a 
  landslide 
  structure, 
  a 
  pro- 
  

   cess 
  which 
  presumably 
  has 
  been 
  continuous 
  since 
  the 
  suggestive 
  

   name 
  was 
  given 
  to 
  the 
  irregular 
  projection 
  which 
  these 
  clays 
  make 
  

   on 
  the 
  beach. 
  They 
  move 
  with 
  something 
  like 
  glacial 
  flow, 
  over- 
  

   running 
  the 
  normal 
  beach, 
  the 
  wave 
  action 
  being 
  there 
  unequal 
  to 
  

   the 
  task 
  of 
  maintaining 
  a 
  straight 
  shore 
  line. 
  

  

  ^ 
  De 
  la 
  Beche 
  appears 
  to 
  have 
  first 
  made 
  this 
  point 
  in 
  the 
  case 
  of 
  certain 
  British 
  

   beaches. 
  See 
  Geological 
  manual. 
  Phil. 
  1833. 
  p. 
  73-75. 
  

   2 
  Siiess, 
  Edouard. 
  La 
  face 
  de 
  la 
  terre. 
  Paris 
  1900. 
  2 
  : 
  670-89. 
  

  

  