﻿428 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  South 
  of 
  Feurabush 
  the 
  escarpment 
  increases 
  in 
  altitude, 
  and 
  

   extends 
  eastward 
  to 
  the 
  margin 
  of 
  the 
  plain 
  of 
  which 
  it 
  thence 
  

   constitutes 
  the 
  western 
  boundary 
  to 
  the 
  southeastern 
  corner 
  of 
  

   the 
  county. 
  It 
  here 
  presents 
  its 
  usual 
  characteristics 
  of 
  long 
  walls 
  

   of 
  limestone 
  cliffs, 
  but 
  the 
  altitude 
  above 
  the 
  plain 
  here 
  averages 
  

   only 
  about 
  200 
  feet. 
  Opposite 
  South 
  Bethlehem 
  the 
  escarpment 
  

   is 
  broken 
  through 
  by 
  Oniskethau 
  creek 
  and 
  the 
  Spraytkill. 
  

  

  In 
  New 
  Scotland 
  and 
  Coeymans 
  townships 
  the 
  plateaus 
  and 
  

   terraces 
  above 
  the 
  Helderberg 
  escarpment 
  have 
  a 
  width 
  varying 
  

   from 
  two 
  to 
  four 
  miles. 
  They 
  present 
  a 
  considerable 
  variety 
  of 
  

   surface 
  features 
  owing 
  to 
  the 
  erosion 
  to 
  which 
  they 
  have 
  been 
  

   subjected 
  by 
  the 
  Oniskethau 
  and 
  Hannecrois 
  creeks 
  and 
  their 
  

   branches. 
  These 
  streams 
  have 
  cut 
  irregular 
  valleys 
  of 
  consider- 
  

   able 
  width 
  across 
  the 
  terraces 
  and 
  isolated 
  a 
  number 
  of 
  abrupt 
  

   ridges, 
  especially 
  to 
  the 
  southward. 
  

  

  Southwestern 
  townships. 
  — 
  The 
  highly 
  elevated 
  region 
  of 
  the 
  

   southwestern 
  third 
  of 
  the 
  county 
  presents 
  a 
  great 
  variety 
  of 
  

   topographic 
  form. 
  Its 
  general 
  character 
  is 
  a 
  high 
  plateau 
  deeply 
  

   and 
  widely 
  invaded 
  by 
  a 
  complex 
  system 
  of 
  valleys 
  which 
  have 
  

   reduced 
  the 
  greater 
  part 
  of 
  the 
  area 
  to 
  a 
  series 
  of 
  slopes. 
  A 
  

   noteworthy 
  feature 
  of 
  the 
  region 
  is 
  the 
  very 
  steep 
  front 
  which 
  

   it 
  presents 
  to 
  the 
  north 
  and 
  to 
  the 
  east, 
  which 
  rises 
  from 
  400 
  to 
  

   500 
  feet 
  abruptly 
  from 
  the 
  upper 
  terrace 
  behind 
  the 
  Helderberg 
  

   escarpment. 
  This 
  front 
  extends 
  almost 
  due 
  east 
  through 
  the 
  

   northern 
  part 
  of 
  Berne 
  township 
  and 
  then 
  turns 
  abruptly 
  south- 
  

   ward 
  and 
  extends 
  along 
  the 
  eastern 
  front 
  of 
  the 
  Helderberg 
  

   mountains 
  to 
  Clarksville. 
  South 
  from 
  Clarksville, 
  in 
  Bennett, 
  

   Copeland 
  and 
  Blodgett 
  hills, 
  it 
  offsets 
  to 
  the 
  eastward 
  in 
  a 
  series 
  

   of 
  ridges 
  very 
  abruptly 
  terminated 
  northward. 
  A 
  reference 
  to 
  

   the 
  topographic 
  base 
  map 
  accompanying 
  this 
  report 
  will, 
  I 
  believe, 
  

   be 
  the 
  most 
  satisfactory 
  means 
  of 
  forming 
  a 
  conception 
  of 
  the 
  

   nature 
  of 
  these 
  curious 
  offsets. 
  

  

  The 
  hills 
  of 
  this 
  southwestern 
  region 
  increase 
  in 
  altitude 
  to 
  the 
  

   north 
  and 
  west 
  from 
  about 
  1000 
  feet 
  in 
  Coeymans 
  township 
  to 
  

   1700 
  feet 
  in 
  the 
  northern 
  part 
  of 
  the 
  Helderberg 
  mountain, 
  and 
  

   over 
  2000 
  feet 
  west 
  of 
  Kensselaerville. 
  To 
  the 
  north 
  the 
  region 
  

   is 
  deeply 
  invaded 
  by 
  the 
  Switzkill, 
  which 
  has 
  cut 
  a 
  deep, 
  steep- 
  

   sided 
  valley 
  extending 
  far 
  southward. 
  From 
  the 
  west 
  it 
  is 
  

  

  