﻿26 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  the 
  southern 
  end 
  and 
  the 
  western 
  fork 
  interrupted 
  by 
  a 
  cross 
  fold 
  at 
  

   the 
  Harlem 
  River, 
  ends 
  on 
  Manhattan 
  Island 
  in 
  the 
  low 
  ridge 
  which 
  

   borders 
  Seventh 
  avenue 
  on 
  the 
  west 
  at 
  One 
  Hundred 
  and 
  Fifty-fifth 
  

   street, 
  and 
  disappears 
  by 
  pitching 
  below 
  the 
  general 
  surface 
  level 
  

   about 
  half 
  a 
  mile 
  southward. 
  The 
  eastern 
  fork 
  which, 
  owing 
  to 
  the 
  

   same 
  cross 
  fold, 
  disappears 
  beneath 
  the 
  Hmestone 
  in 
  Morrisania, 
  

   reappears 
  near 
  the 
  Bronx 
  Kills 
  in 
  Mott 
  Haven, 
  vv^here 
  it 
  forms 
  a 
  low 
  

   anticlinal 
  ridge 
  interrupted 
  by 
  the 
  Kills 
  and 
  represented 
  on 
  Manhat- 
  

   tan 
  Island 
  by 
  a 
  few 
  outcrops 
  below 
  high 
  water 
  mark 
  at 
  the 
  foot 
  of 
  

   East 
  123rd 
  and 
  125th 
  streets 
  which 
  are 
  now 
  obliterated. 
  Some 
  nar- 
  

   row 
  anticlinal 
  ridges 
  of 
  Fordham 
  gneiss 
  are 
  seen 
  on 
  the 
  islands 
  in 
  

   the 
  East 
  River, 
  notably 
  Blackw 
  ell's. 
  Ward's, 
  N. 
  Brother's 
  and 
  S. 
  

   Brother's, 
  and 
  it 
  is 
  the 
  only 
  stratified 
  crystalline 
  rock 
  at 
  present 
  

   exposed 
  on 
  Long 
  Island, 
  where 
  it 
  may 
  be 
  seen 
  near 
  the 
  court 
  house 
  

   in 
  Long 
  Island 
  City 
  and 
  at 
  intervals 
  on 
  or 
  near 
  the 
  shore 
  of 
  the 
  East 
  

   River 
  from 
  Ravenswood 
  to 
  Lawrence's 
  Point. 
  

  

  PALAEOZOIC. 
  

  

  At 
  the 
  base 
  of 
  the 
  metamorphosed 
  Palaeozoic 
  limestone 
  and 
  over- 
  

   lying 
  the 
  Fordham 
  gneiss 
  is 
  a 
  stratum 
  of 
  thinly 
  bedded 
  quartzite. 
  

   This 
  deposit 
  occurs 
  in 
  southern 
  Westchester 
  county 
  near 
  Lowerre 
  

   station 
  in 
  Yonkers 
  at 
  the 
  Hastings 
  marble 
  quarry 
  and 
  about 
  one- 
  

   quarter 
  mile 
  south 
  of 
  Sparta 
  on 
  the 
  shore 
  of 
  the 
  Hudson 
  River. 
  It 
  is 
  

   well 
  shown 
  north 
  of 
  Peekskill 
  along 
  the 
  east 
  shore 
  of 
  Annsville 
  

   Cove 
  and 
  in 
  the 
  valley 
  of 
  Peekskill 
  Hollow 
  Creek 
  near 
  Oregon. 
  

   It 
  does 
  not 
  exceed 
  sixteen 
  feet 
  in 
  thickness 
  at 
  Hastings. 
  From 
  the 
  

   name 
  of 
  the 
  southern 
  locality 
  this 
  is 
  called 
  the 
  Lowerre 
  quartzite. 
  

   Its 
  age 
  is 
  probably 
  Cambrian 
  and 
  possibly 
  Georgian. 
  

  

  INWOOD 
  LIMESTONE. 
  

  

  This 
  is 
  one 
  of 
  the 
  most 
  prominent 
  formations 
  of 
  the 
  region 
  mapped 
  

   and 
  is 
  a 
  coarsely 
  crystalline 
  dolomite, 
  distinctly 
  bedded 
  and 
  contain- 
  

   ing 
  at 
  many 
  localities 
  the 
  lime-magnesia 
  silicates, 
  diopside 
  and 
  tremo- 
  

   lite, 
  and 
  occasionally 
  tourmaline. 
  Of 
  its 
  maximum 
  thickness 
  little 
  

   is 
  definitely 
  known. 
  At 
  Tuckahoe 
  a 
  thickness 
  of 
  one 
  hundred 
  and 
  

  

  