﻿l6 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  region, 
  and 
  great 
  masses 
  of 
  igneous 
  rocks 
  have 
  been 
  forced 
  through 
  

   these. 
  All 
  these 
  rocks 
  have 
  been 
  subjected 
  to 
  tremendous 
  earth 
  

   pressure 
  which 
  has 
  folded 
  and 
  thoroughly 
  metamorphosed 
  them. 
  

  

  SOUTHWESTERN 
  PLATEAU 
  PROVINCE 
  

  

  This, 
  the 
  largest 
  clearly 
  defined 
  physiographic 
  province, 
  occupies 
  

   nearly 
  one-third 
  of 
  the 
  area 
  of 
  the 
  State. 
  The 
  rocks 
  are 
  all 
  

   unaltered 
  sediments 
  of 
  Devonic 
  age, 
  except 
  a 
  few 
  small 
  patches 
  

   of 
  Carbonic 
  rocks 
  in 
  the 
  southwest, 
  and 
  consist 
  of 
  shales, 
  sandstones, 
  

   and 
  conglomerates. 
  These 
  formations 
  exist 
  as 
  vast 
  sheets 
  or 
  layers 
  

   piled 
  one 
  upon 
  another, 
  with 
  an 
  aggregate 
  thickness 
  of 
  several 
  thou- 
  

   sand 
  feet 
  (see 
  figures 
  3 
  and 
  5). 
  In 
  marked 
  contrast 
  to 
  the 
  Adiron- 
  

   dack 
  province, 
  the 
  rock 
  masses 
  of 
  this 
  southwestern 
  plateau 
  are 
  

   practically 
  devoid 
  of 
  displacements, 
  the 
  only 
  disturbance 
  being 
  a 
  

   slight 
  tilt 
  (30 
  to 
  50 
  feet 
  a 
  mile) 
  of 
  all 
  the 
  strata 
  to 
  the 
  south 
  or 
  

   southwest, 
  associated 
  with 
  low 
  northeast-southwest 
  undulation. 
  

  

  Although 
  this 
  plateau 
  is 
  pretty 
  well 
  trenched 
  or 
  dissected 
  by 
  

   streams, 
  it 
  is 
  nevertheless 
  not 
  a 
  mountainous 
  country, 
  there 
  being 
  

   no 
  high 
  ranges 
  or 
  peaks 
  standing 
  out 
  prominently. 
  The 
  elevation 
  

   of 
  the 
  province 
  varies 
  from 
  500 
  to 
  600 
  feet 
  on 
  the 
  northern 
  side 
  

   to 
  over 
  2000 
  feet 
  on 
  the 
  eastern 
  and 
  western 
  sides. 
  A 
  notable 
  

   feature 
  is 
  the 
  distinct 
  sagging 
  of 
  the 
  plateau 
  toward 
  the 
  middle 
  

   portion. 
  This 
  sagged 
  or 
  depressed 
  portion 
  is 
  occupied 
  by 
  the 
  Finger 
  

   Lakes, 
  especially 
  that 
  portion 
  filled 
  by 
  the 
  south 
  ends 
  of 
  Cayuga 
  

   and 
  Seneca 
  lakes 
  and 
  the 
  valleys 
  which 
  enter 
  them 
  from 
  the 
  south 
  

   in 
  the 
  region 
  of 
  Chemung 
  and 
  Tioga 
  counties. 
  It 
  is 
  possible, 
  by 
  

   traveling 
  along 
  Seneca 
  lake 
  and 
  thence 
  southward 
  to 
  Elmira 
  and 
  

   the 
  Chemung 
  river, 
  to 
  pass 
  entirely 
  across 
  the 
  plateau 
  province 
  

   from 
  north 
  to 
  south 
  without 
  attaining 
  an 
  altitude 
  of 
  much 
  over 
  

   900 
  feet, 
  which 
  is 
  on 
  the 
  divide 
  between 
  Watkins 
  and 
  Elmira. 
  

  

  Physiographically, 
  the 
  Plateau 
  province 
  is 
  really 
  but 
  the 
  north- 
  

   ernmost 
  extension 
  of 
  the 
  great 
  plateau 
  which 
  lies 
  along 
  the 
  western 
  

   base 
  of 
  the 
  Appalachian 
  mountains. 
  On 
  the 
  east 
  the 
  province 
  is 
  

   bounded 
  by 
  the 
  Catskill 
  mountains 
  which 
  are 
  in 
  no 
  sense 
  sharply 
  

   separated 
  from 
  the 
  plateau 
  itself. 
  On 
  the 
  west 
  and 
  north 
  the 
  

   province 
  is 
  bounded 
  by 
  the 
  Erie-Ontario 
  plain 
  and 
  Mohawk 
  valley 
  

   provinces. 
  The 
  northern 
  limit 
  is 
  pretty 
  clearly 
  marked 
  by 
  what 
  

   is 
  known 
  as 
  the 
  " 
  Helderberg 
  escarpment 
  " 
  of 
  Devonic 
  limestone. 
  

   This 
  limestone, 
  being 
  of 
  considerable 
  thickness 
  and 
  more 
  resistant 
  

   than 
  the 
  neighboring 
  formations, 
  has 
  generally 
  stood 
  out 
  boldly 
  

   against 
  erosion, 
  thus 
  causing 
  an 
  abrupt 
  change 
  in 
  relief. 
  The 
  

   escarpment 
  is 
  particularly 
  prominent 
  along 
  the 
  boundary 
  of 
  the 
  

  

  