﻿394 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  field 
  work, 
  being 
  for 
  the 
  greater 
  part 
  of 
  the 
  time 
  accompanied 
  

   by 
  the 
  State 
  Geologist. 
  This 
  report 
  is 
  a 
  description 
  of 
  the 
  results. 
  

   The 
  stratigraphy 
  and 
  the 
  general 
  relations 
  of 
  the 
  formations 
  

   about 
  Schoharie 
  and 
  the 
  Helderberg 
  mountains 
  are 
  already 
  well 
  

   known 
  through 
  the 
  geological 
  and 
  palaeontological 
  reports 
  of 
  the 
  

   New 
  York 
  Survey, 
  and 
  in 
  these 
  regions 
  about 
  all 
  I 
  have 
  to 
  offer 
  

   as 
  new 
  are 
  the 
  details 
  of 
  distribution 
  shown 
  on 
  the 
  map 
  and 
  some 
  

   measurements 
  of 
  thickness 
  and 
  dip. 
  For 
  the 
  relations 
  of 
  the 
  

   Helderberg 
  formation 
  in 
  the 
  folded 
  region 
  which 
  was 
  found 
  to 
  

   extend 
  from 
  the 
  Helderberg 
  mountains 
  southward 
  to 
  the 
  Shawan. 
  

   gunk 
  mountains, 
  there 
  are 
  no 
  reliable 
  data 
  on 
  record, 
  excepting 
  

   for 
  an 
  area 
  just 
  west 
  of 
  Catskill 
  and 
  another 
  about 
  Eondout 
  

   which 
  were 
  worked 
  out 
  in 
  great 
  detail 
  by 
  Professor 
  W. 
  M. 
  Davis.* 
  

   The 
  complicated 
  structure 
  of 
  the 
  very 
  important 
  cement 
  region 
  

   about 
  Eosendale 
  and 
  the 
  interesting 
  relations 
  on 
  the 
  wide 
  northern 
  

   end 
  of 
  Shawangunk 
  mountains 
  have 
  never 
  before 
  been 
  fully 
  

   described. 
  

  

  Physiography. 
  

  

  The 
  region 
  occupied 
  by 
  the 
  Helderberg 
  and 
  associated 
  forma- 
  

   tions 
  in 
  eastern 
  New 
  York 
  presents 
  a 
  considerable 
  variety 
  of 
  

   physical 
  features 
  closely 
  related 
  to 
  the 
  rocks 
  and 
  their 
  structure, 
  

   so 
  that 
  a 
  brief 
  consideration 
  of 
  the 
  physiography 
  will 
  aid 
  in 
  the 
  

   elucidation 
  of 
  the 
  geology. 
  The 
  principal 
  features 
  in 
  which 
  we 
  

   are 
  concerned 
  are 
  the 
  great 
  Helderberg 
  escarpment, 
  the 
  series 
  of 
  

   parallel 
  ridges 
  of 
  Appalachian 
  type 
  to 
  which 
  it 
  gives 
  place 
  from 
  

   Albany 
  county 
  southward, 
  and 
  the 
  great 
  Shawangunk 
  mountain 
  into 
  

   which 
  these 
  ridges 
  merge 
  in 
  central 
  Ulster 
  county. 
  To 
  the 
  south 
  

   of 
  the 
  escarpment 
  and 
  west 
  of 
  the 
  series 
  of 
  ridges 
  and 
  the 
  

   Shawangunk 
  mountain 
  are 
  the 
  high 
  hills 
  and 
  elevated 
  terrace 
  of 
  

   the 
  Hamilton 
  formation. 
  To 
  the 
  north 
  and 
  east 
  are 
  the 
  steep 
  

   slopes 
  ending 
  in 
  the 
  wide 
  terrace 
  of 
  the 
  Mohawk 
  and 
  Hudson, 
  

   excepting 
  south 
  of 
  Kondout 
  where 
  the 
  terrace 
  gives 
  place 
  to 
  a 
  

   rolling 
  region 
  of 
  Hudson 
  slates 
  and 
  sandstones. 
  

  

  The 
  Helderberg 
  escarpment 
  is 
  the 
  precipitous 
  face 
  of 
  an 
  ele- 
  

   vated, 
  evenly-crested 
  shelf, 
  which 
  extends 
  from 
  west 
  to 
  east 
  

  

  *Tbe 
  Little 
  Mountains 
  east 
  of 
  the 
  Catskills, 
  Appalachia, 
  vol. 
  3, 
  pp. 
  20-33, 
  pi. 
  1. 
  1882. 
  The 
  

   folded 
  Helderberg 
  limestones 
  east 
  of 
  the 
  Catskills, 
  Harvard 
  Coll. 
  Mus. 
  Comp. 
  Zool., 
  Bull. 
  vol. 
  7, 
  

   dp. 
  311-329, 
  pis. 
  12, 
  13. 
  1883. 
  The 
  Nonconformity 
  at 
  Rondout, 
  N. 
  Y. 
  Am. 
  Jour. 
  Sci. 
  (3d 
  series), 
  

   vol. 
  26, 
  pp. 
  389-395. 
  1883. 
  

  

  