﻿632 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  tlie 
  Manhasset 
  sands. 
  The 
  deposit, 
  now 
  largely 
  removed 
  for 
  

   mason's 
  supplies, 
  exhibits 
  a 
  strong 
  flexure 
  with 
  a 
  downthrow 
  to 
  the 
  

   south. 
  On 
  either 
  side 
  of 
  this 
  flexure 
  the 
  beds 
  are 
  horizontal 
  but 
  

   those 
  on 
  the 
  north 
  belong 
  stratigraphicallj 
  below 
  those 
  now 
  on 
  the 
  

   same 
  level 
  but 
  on 
  the 
  south 
  of 
  tlie 
  flexure. 
  The 
  annexed 
  cut 
  

   (flg. 
  8) 
  as 
  sketched 
  from 
  a 
  photograph 
  exhibits 
  the 
  sand 
  beds 
  in 
  

   the 
  top 
  of 
  flexure. 
  The 
  truncation 
  of 
  the 
  flexed 
  beds 
  at 
  the 
  

   present 
  surface 
  is 
  sufiicient 
  evidence 
  of 
  the 
  erosion 
  of 
  the 
  whole 
  to 
  

   its 
  present 
  level. 
  A 
  few 
  small 
  glacial 
  erratics 
  occur 
  on 
  the 
  surface, 
  

   but 
  the 
  ice 
  sheet 
  appears 
  to 
  have 
  swept 
  over 
  it 
  without 
  leaving 
  

   other 
  deposits. 
  The 
  top 
  sands 
  have 
  lost 
  their 
  stratification 
  but 
  it 
  is 
  

   impossible 
  to 
  say 
  how 
  far 
  this 
  disturbance 
  was 
  due 
  to 
  the 
  ice 
  sheet 
  

   and 
  how 
  much 
  has 
  been 
  done 
  by 
  the 
  growth 
  of 
  plant 
  roots 
  in 
  the 
  

   subsoil. 
  

  

  The 
  small 
  heads 
  of 
  Cretaceous 
  clay 
  appearing 
  above 
  sealevel 
  on 
  the 
  

   shore 
  of 
  Manhasset 
  bay, 
  where 
  the 
  older 
  Pleistocene 
  is 
  essentially 
  

   horizontal, 
  along 
  with 
  the 
  protruding 
  masses 
  of 
  these 
  older 
  clays 
  in 
  the 
  

   Qiassive 
  portions 
  of 
  the 
  section, 
  indicate 
  a 
  relatively 
  early 
  disloca- 
  

   tion 
  of 
  por- 
  

   tions 
  of 
  the 
  

   pre- 
  Pleisto- 
  

   cene 
  base- 
  

   ment 
  of 
  the 
  

   island. 
  It 
  

   would 
  there- 
  

   fore 
  appear 
  

   that 
  the 
  dislo- 
  

   cations 
  were 
  

   not 
  all 
  of 
  the 
  

   same 
  date 
  in 
  this 
  portion 
  of 
  the 
  island, 
  ranging 
  in 
  age 
  from 
  at 
  least 
  

   the 
  oldest 
  Pleistocene 
  to 
  the 
  time 
  of 
  the 
  main 
  moraines, 
  certainly 
  

   Qone 
  of 
  them 
  are 
  later 
  than 
  the 
  Port 
  Washington 
  stage. 
  

  

  The 
  upper 
  limit 
  of 
  the 
  Columbia 
  accords 
  roughly 
  with 
  the 
  hight 
  

   assigned 
  to 
  the 
  plains 
  described 
  as 
  lying 
  north 
  of 
  the 
  inner 
  moraine, 
  

   that 
  is 
  to 
  say, 
  the 
  deposits 
  are 
  approximately 
  delimited 
  by 
  the 
  200 
  

   foot 
  contour 
  line. 
  Where 
  lower, 
  they 
  have 
  been 
  eroded; 
  where 
  

   higher 
  surfaces 
  exist, 
  later 
  glacial 
  drift, 
  usually 
  till, 
  is 
  found 
  cover- 
  

  

  Fig. 
  8 
  Southward 
  dipping 
  flexed 
  beds 
  in 
  Manhasset 
  sands 
  at 
  Tom 
  point 
  

   near 
  Port 
  Washington, 
  showing 
  eroded 
  surface 
  

  

  