﻿of 
  the 
  Northern 
  Appalachians. 
  

  

  345 
  

  

  maturity 
  during 
  a 
  later 
  cycle 
  [the 
  Harrisburg?] 
  and 
  is 
  

   now 
  in 
  a 
  stage 
  of 
  earliest 
  youth 
  with 
  respect 
  to 
  the 
  pres- 
  

   ent 
  river 
  level. 
  On 
  the 
  other 
  hand, 
  the 
  Oriskany 
  sand- 
  

   stone 
  is 
  weaker 
  than 
  the 
  Hamilton; 
  it 
  is 
  sapped 
  from 
  

   two 
  sides 
  and 
  eroded 
  to 
  an 
  average 
  level 
  200 
  feet 
  lower 
  

   than 
  the 
  latter, 
  yet 
  two 
  residual 
  masses 
  (see 
  profile) 
  rise 
  

   to 
  the 
  same 
  height 
  as 
  the 
  many 
  hilltops 
  on 
  the 
  Hamilton 
  

   outcrop 
  west 
  of 
  the 
  river. 
  This 
  is 
  additional 
  evidence 
  

   of 
  the 
  reality 
  of 
  the 
  900-950 
  erosion 
  surface. 
  

  

  Fig. 
  11. 
  

  

  Fig. 
  11. 
  — 
  Projected 
  profile 
  of 
  valley 
  of 
  Delaware 
  Eiver 
  for 
  15 
  miles 
  up 
  

   stream 
  from 
  Port 
  Jervis, 
  N. 
  J. 
  

  

  Another 
  interesting 
  locality 
  is 
  shown 
  on 
  the 
  Milford 
  

   (Pa.) 
  and 
  Port 
  Jervis 
  (N. 
  J.) 
  quadrangles 
  where 
  the 
  

   Delaware 
  River 
  flows 
  southeastward 
  in 
  a 
  deep 
  and 
  nar- 
  

   row 
  gorge 
  across 
  a 
  plateau 
  1,300 
  to 
  1,600 
  feet 
  in 
  elevation 
  

   the 
  surface 
  of 
  which 
  is 
  characterized 
  by 
  low 
  hills 
  and 
  

   swamps. 
  The 
  dissected 
  edge 
  of 
  this 
  plateau 
  forms 
  the 
  

   northwest 
  margin 
  of 
  the 
  projected 
  profile 
  of 
  the 
  Wall- 
  

   pack 
  locality 
  shown 
  in 
  fig. 
  10. 
  The 
  projected 
  profile 
  of 
  

   the 
  Delaware 
  through 
  this 
  plateau 
  in 
  the 
  Milford-Port 
  

   Jervis 
  region 
  is 
  shown 
  in 
  fig. 
  11 
  ; 
  it 
  extends 
  15 
  miles 
  up 
  

  

  