﻿624 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Columbia 
  formation. 
  The 
  rude 
  terraced 
  jAsiins 
  lying 
  north 
  of 
  

   the 
  main 
  moraine 
  on 
  the 
  Oyster 
  Bay 
  quadrangle 
  are 
  but 
  the 
  surface 
  

   of 
  a 
  thick 
  series 
  of 
  gravels 
  and 
  sands 
  on 
  which 
  the 
  moraines 
  have 
  

   been 
  heaped. 
  The 
  reasons 
  for 
  referring 
  to 
  tliem 
  heretofore 
  as 
  older 
  

   Pleistocene 
  may 
  now 
  be 
  set 
  forth, 
  together 
  with 
  the 
  evidence 
  in 
  

   favor 
  of 
  referring 
  them 
  to 
  the 
  Columbia 
  formation 
  of 
  McGee/ 
  the 
  

   group 
  to 
  w^hich 
  the 
  deposits 
  appear 
  to 
  have 
  been 
  referred 
  by 
  that 
  

   author, 
  in 
  1888. 
  

  

  F. 
  J. 
  H. 
  Merrill, 
  following 
  the 
  pioneer 
  work 
  of 
  Mather, 
  pointed 
  

   out 
  in 
  1886 
  that 
  these 
  gravels 
  and 
  sands 
  under 
  the 
  name 
  of 
  "gravel 
  

   drift" 
  underlie 
  unconformably 
  the 
  moraine, 
  and 
  concluded 
  that 
  

   they 
  were 
  deposited 
  by 
  swift 
  currents 
  carrying 
  along 
  line 
  and 
  coarse 
  

   materials 
  together.'^ 
  

  

  The 
  deposits 
  as 
  exposed 
  on 
  the 
  Oyster 
  Bay 
  quadrangle 
  consist 
  of 
  

   water-worn 
  gravels 
  and 
  sands, 
  clearly 
  divisible 
  in 
  certain 
  sections 
  

   into 
  an 
  upper 
  and 
  lower 
  series 
  by 
  a 
  thin 
  bed 
  of 
  glacial 
  boulder 
  clay. 
  

   It 
  has 
  not 
  been 
  possible 
  in 
  the 
  course 
  of 
  the 
  present 
  survey 
  within 
  

   the 
  area 
  to 
  determine 
  whether 
  or 
  not 
  the 
  group 
  thus 
  defined 
  is 
  to 
  

   be 
  divided 
  into 
  an 
  earlier 
  dislocated 
  and 
  a 
  later 
  undisturbed 
  series, 
  

   but 
  it 
  is 
  clear 
  that 
  many 
  sections 
  of 
  these 
  gravels, 
  along 
  with 
  v/hat 
  

   appears 
  to 
  be 
  the 
  boulder 
  bed 
  named, 
  have 
  been 
  dislocated 
  along 
  the 
  

   north 
  coast 
  of 
  the 
  island. 
  On 
  Marthas 
  Vineyard 
  and 
  Block 
  island 
  

   such 
  a 
  division 
  has 
  been 
  made 
  out,^ 
  but 
  the 
  boulder 
  clay 
  parting, 
  on 
  

   the 
  other 
  hand, 
  has 
  not 
  been 
  found 
  there 
  in 
  the 
  position 
  of 
  an 
  inter- 
  

   mediate 
  conformable 
  bed. 
  

  

  The 
  gravels 
  consist 
  of 
  water-worn 
  fragments 
  of 
  quartz 
  derived 
  

   from 
  veins, 
  granite 
  and 
  gneiss 
  from 
  the 
  ancient 
  Piedmont 
  terrane 
  of 
  

   the 
  mainland, 
  of 
  silicified 
  fossils 
  from 
  the 
  metamorphic 
  Paleozoic 
  

   limestones 
  of 
  the 
  mainland, 
  cherts 
  of 
  the 
  same 
  origin, 
  and 
  ferrugin- 
  

   ous 
  sandstones 
  and 
  fragments 
  of 
  concretions 
  from 
  the 
  underlying 
  

   Cretaceous 
  or 
  Potomac 
  section. 
  

  

  ^3IcGee, 
  W 
  J. 
  Three 
  formations 
  of 
  the 
  middle 
  Atlantic 
  slope. 
  Am. 
  jour, 
  

   sci. 
  Ser. 
  3. 
  1888. 
  35 
  : 
  367-88, 
  448-66. 
  It 
  has 
  not 
  seemed 
  possible 
  at 
  present 
  to 
  

   establish 
  a 
  satisfactory 
  comparison 
  of 
  the 
  deposits 
  in 
  this 
  portion 
  of 
  Long 
  Island 
  

   with 
  the 
  formations 
  recognized 
  in 
  New 
  Jersey 
  by 
  Prof. 
  Salisbury. 
  

  

  2 
  Merrill, 
  F. 
  J. 
  H. 
  N. 
  Y. 
  acad. 
  sci. 
  Annals. 
  1886. 
  3 
  : 
  341-64. 
  

  

  ^Woodworth, 
  J. 
  B. 
  Unconformities 
  on 
  Marthas 
  Vineyard 
  and 
  Block 
  island. 
  

   Geol. 
  soc. 
  Am. 
  Bui. 
  1897. 
  8 
  : 
  204-11. 
  

  

  