﻿34:6 
  

  

  J. 
  Barrell 
  — 
  The 
  Piedmont 
  Terraces 
  

  

  the 
  river 
  from 
  Port 
  Jervis. 
  The 
  plateau 
  here 
  has 
  sum- 
  

   mit 
  elevations 
  of 
  about 
  1,500 
  feet 
  and 
  has 
  clearly 
  been 
  

   dissected 
  by 
  an 
  ancient 
  river 
  with 
  respect 
  to 
  a 
  baselevel 
  

   at 
  a 
  present 
  elevation 
  of 
  about 
  1,400 
  feet. 
  This 
  oldest 
  

   valley 
  is 
  seen 
  to 
  have 
  been 
  about 
  six 
  miles 
  wide 
  and 
  200 
  

   feet 
  deep. 
  The 
  river 
  presumably 
  developed 
  a 
  set 
  of 
  

   meanders 
  in 
  this 
  wide 
  flat 
  valley 
  and 
  there 
  would 
  have 
  

   been 
  very 
  flat 
  spurs 
  advancing 
  out 
  to 
  the 
  margins 
  of 
  the 
  

   meander 
  belt. 
  There 
  appear 
  to 
  be 
  traces 
  of 
  such 
  spurs 
  

   close 
  to 
  the 
  1,400 
  ± 
  baselevel, 
  but 
  most 
  of 
  them, 
  in 
  any 
  

   case, 
  would 
  have 
  been 
  sapped 
  by 
  erosion 
  with 
  respect 
  to 
  

   lower 
  baselevels. 
  

  

  Fig. 
  12. 
  

  

  

  

  

  

  

  - 
  

  

  I60C 
  

  

  

  VM 
  

  

  \J%£~\ 
  

  

  ^^o 
  

  

  \0\< 
  

  

  

  1600 
  

  

  ISOO 
  

  

  

  

  

  

  1500 
  

  

  I4O0 
  

  

  W- 
  

  

  W?\^L 
  

  

  ^l^\ 
  n 
  

  

  \J1I1 
  

  

  

  

  I4O0 
  

  

  I3O0 
  

   1200 
  

  

  

  

  

  \\9yy%yy 
  

  

  

  

  1300 
  

   1200 
  

  

  IIOO 
  

  

  

  

  

  

  

  

  1100 
  

  

  1000 
  

   900 
  

  

  

  ^yyyy>\ 
  

  

  *• 
  o 
  r 
  

  

  2 
  3 
  Miles' 
  

  

  lltl 
  

  

  'Wz 
  

  

  1000 
  

   900 
  

  

  S 
  / 
  S 
  / 
  ■/ 
  . 
  

  

  

  

  

  

  

  

  

  

  Fig. 
  12. 
  — 
  Projected 
  profile 
  of 
  part 
  of 
  the 
  Montieello 
  (Pa.) 
  quadrangle. 
  

   View 
  looking 
  north. 
  

  

  A 
  section 
  of 
  the 
  oldest 
  erosion 
  surface 
  as 
  it 
  appears 
  on 
  

   the 
  Montieello 
  quadrangle 
  is 
  shown 
  in 
  fig. 
  12. 
  It 
  em- 
  

   braces 
  an 
  area 
  about 
  9 
  by 
  6 
  miles, 
  with 
  Montieello 
  in 
  the 
  

   northeast 
  corner, 
  the 
  direction 
  of 
  view 
  being 
  north. 
  The 
  

   plateau 
  is 
  here 
  slightly 
  higher 
  than 
  at 
  the 
  localities 
  just 
  

   described 
  and 
  is 
  trenched 
  by 
  the 
  valley 
  of 
  the 
  Neversink 
  

   River. 
  It 
  is 
  underlaid 
  by 
  the 
  Catskill 
  sandstones 
  and 
  

   shales 
  dipping 
  gently 
  to 
  the 
  northwest. 
  The 
  surface 
  

   thus 
  bevels 
  across 
  the 
  formation 
  and 
  the 
  higher 
  hills 
  

   mark 
  outcrops 
  of 
  the 
  harder 
  beds. 
  This 
  beveling 
  of 
  the 
  

   ancient 
  structure 
  shows 
  that 
  the 
  upland 
  is 
  a 
  peneplaned 
  

   surface 
  which 
  originally 
  had 
  a 
  high 
  degree 
  of 
  perfection. 
  

   The 
  topography 
  of 
  the 
  part 
  covered 
  by 
  the 
  Montieello 
  

   quadrangle 
  indicates 
  that' 
  this 
  plane, 
  which 
  is 
  assigned 
  

  

  