﻿of 
  the 
  Northern 
  Appalachians. 
  237 
  

  

  of 
  Science. 
  The 
  most 
  significant 
  conclusion 
  in 
  the 
  pres- 
  

   ent 
  connection 
  was 
  that 
  derived 
  from 
  a 
  study 
  of 
  the 
  wind 
  

   and 
  water 
  gaps 
  across 
  Kittatinny 
  mountain. 
  From 
  New 
  

   York 
  to 
  Maryland, 
  and 
  even 
  farther 
  south, 
  this 
  resistant 
  

   quartzite 
  ridge 
  rises 
  boldly 
  above 
  the 
  valleys 
  on 
  either 
  

   side, 
  its 
  summit 
  maintaining 
  a 
  remarkably 
  uniform 
  ele- 
  

   vation 
  of 
  1,500 
  to 
  1,700 
  feet 
  through 
  most 
  of 
  the 
  distance. 
  

   In 
  a 
  few 
  places, 
  however, 
  it 
  rises 
  distinctly 
  above 
  this 
  

   level 
  and 
  at 
  others, 
  more 
  especially 
  near 
  stream 
  channels, 
  

   it 
  falls 
  below 
  it. 
  Ridges 
  of 
  the 
  same 
  general 
  elevation 
  

   lie 
  farther 
  to 
  the 
  northwest 
  and 
  all 
  clearly 
  represent 
  

   eroded 
  remnants 
  of 
  a 
  former 
  peneplane. 
  

  

  The 
  Kittatinny 
  ridge 
  is 
  cut 
  by 
  the 
  major 
  streams 
  and 
  

   by 
  some 
  of 
  lesser 
  volume, 
  such 
  as 
  the 
  Swatara. 
  "Wind 
  

   gaps 
  spaced 
  between 
  the 
  water 
  gaps 
  5 
  show 
  that 
  in 
  the 
  

   first 
  cycle 
  of 
  uplift 
  after 
  the 
  formation 
  of 
  the 
  peneplane 
  

   many 
  minor 
  streams 
  flowed 
  across 
  this 
  ridge. 
  The 
  

   drainage 
  at 
  the 
  time 
  of 
  uplift, 
  therefore, 
  was 
  not 
  ad- 
  

   justed 
  to 
  structure 
  but 
  was 
  superposed 
  across 
  a 
  most 
  

   resistant 
  formation. 
  

  

  In 
  the 
  time 
  that 
  has 
  elapsed 
  since 
  the 
  uplift 
  of 
  the 
  

   Kittatinny 
  peneplain 
  broad 
  lowlands 
  have 
  been 
  devel- 
  

   oped 
  while 
  the 
  resistant 
  quartzite 
  has 
  been 
  but 
  slightly 
  

   touched 
  by 
  erosion 
  and 
  still 
  shows 
  nearly 
  original 
  levels. 
  

   Such 
  loss 
  as 
  it 
  has 
  suffered 
  has 
  been 
  through 
  the 
  devel- 
  

   opment 
  of 
  steep 
  slopes 
  by 
  the 
  erosion 
  of 
  adjacent 
  soft 
  

   formations. 
  Let 
  ten 
  times 
  the 
  period 
  pass 
  away 
  which 
  

   has 
  elapsed 
  since 
  the 
  uplift 
  of 
  the 
  Kittatinny 
  peneplain 
  

   and, 
  if 
  only 
  subaerial 
  denudation 
  were 
  concerned, 
  the 
  

   ridge 
  would 
  still 
  stand 
  up 
  with 
  flattened 
  slopes 
  rising 
  

   several 
  hundred 
  feet 
  above 
  the. 
  adjacent 
  lowlands. 
  That 
  

   is 
  to 
  say, 
  the 
  notable 
  persistence 
  of 
  Kittatinny 
  Ridge 
  

   through 
  at 
  least 
  two 
  later 
  cycles 
  of 
  erosion 
  raises 
  the 
  

   very 
  strong 
  presumption 
  that 
  the 
  rock 
  which 
  forms 
  it 
  

   would 
  have 
  stood 
  as 
  a 
  well-defined 
  ridge 
  above 
  the 
  more 
  

   perfectly 
  baseleveled 
  lowlands 
  at 
  the 
  close 
  of 
  the 
  Creta- 
  

   ceous 
  period 
  of 
  peneplanation. 
  Therefore, 
  during 
  the 
  

   prolonged 
  erosion 
  cycles 
  leading 
  up 
  to 
  the 
  Kittatinny 
  

   peneplain, 
  the 
  streams 
  should 
  have 
  become 
  thoroughly 
  

   adjusted 
  to 
  structure 
  and 
  only 
  at 
  wide 
  intervals 
  should 
  

   master 
  streams 
  have 
  crossed 
  the 
  resistant 
  ridges 
  in 
  long- 
  

   inherited 
  courses. 
  How, 
  then, 
  did 
  such 
  a 
  degree 
  of 
  

  

  5 
  [Presumably 
  the 
  depressions 
  along 
  the 
  summit 
  of 
  the 
  ridge 
  rather 
  than 
  

   the 
  well 
  marked 
  wind 
  gaps, 
  like 
  Pen 
  Argyl, 
  at 
  lower 
  elevations. 
  — 
  Editor.] 
  

  

  