﻿420 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  There 
  is 
  a 
  small 
  overlap 
  feature 
  in 
  the 
  southwestern 
  corner 
  of 
  

   Herkimer 
  county 
  which 
  is 
  of 
  interest. 
  Here 
  I 
  found, 
  as 
  I 
  have 
  

   mentioned 
  above, 
  that 
  the 
  Onondaga 
  limestone 
  lies 
  directly 
  on 
  

   the 
  Pentamerus 
  limestone, 
  the 
  Oriskany 
  and 
  upper 
  members 
  of 
  

   the 
  Helderberg 
  formations 
  having 
  been 
  removed, 
  apparently 
  by 
  

   uplift 
  and 
  erosion, 
  in 
  time 
  just 
  preceding 
  Onondaga 
  deposition. 
  

   The 
  relations 
  are 
  shown 
  in 
  the 
  following 
  figure 
  : 
  

  

  Fig. 
  3.— 
  Section 
  of 
  overlap 
  in 
  southwestern 
  Herkimer 
  county. 
  On., 
  Onondaga 
  limestone; 
  

   O., 
  Oriskany; 
  S., 
  Shaly 
  and 
  Becraft 
  limestone; 
  P., 
  Pentamerus 
  beds; 
  T., 
  Tentaculite 
  lime- 
  

   stone. 
  

  

  The 
  thinning 
  out 
  of 
  the 
  Esopus 
  shales 
  may 
  be 
  correlated 
  with 
  

   this 
  uplift 
  either 
  to 
  erosion 
  by 
  it 
  or 
  their 
  shore 
  cutting 
  off 
  their 
  

   deposition. 
  Possibly, 
  also, 
  the 
  overlap 
  of 
  Onondaga 
  limestone 
  

   on 
  Oriskany 
  and 
  Helderberg 
  limestone 
  westward 
  may 
  be 
  due 
  

   to 
  another 
  area 
  of 
  this 
  uplift. 
  

  

  Structure. 
  

  

  General 
  features. 
  — 
  In 
  western 
  and 
  central 
  New 
  York 
  the 
  

   Palaeozoic 
  rocks 
  lie 
  in 
  a 
  great 
  monocline, 
  dipping 
  gently 
  to 
  the 
  

   southward 
  and 
  traversed 
  by 
  an 
  obscure 
  series 
  of 
  low 
  undula- 
  

   tions* 
  having 
  a 
  north 
  and 
  south 
  trend. 
  This 
  structure 
  is 
  not 
  

   usually 
  perceptible 
  to 
  the 
  eye 
  and 
  the 
  rocks 
  appear 
  to 
  lie 
  flat. 
  

   An 
  occasional 
  local 
  flexure 
  or 
  slip 
  is 
  exposed 
  but 
  they 
  appear 
  

   only 
  to 
  involve 
  beds 
  near 
  the 
  surface. 
  Approaching 
  the 
  Hudson 
  

   river 
  a 
  disturbed 
  region 
  is 
  entered 
  and 
  the 
  undulating 
  monocline 
  

   rapidly 
  gives 
  place 
  to 
  sharp 
  folds, 
  with 
  some 
  faults, 
  which 
  con 
  : 
  

   tinue 
  far 
  eastward. 
  This 
  region 
  of 
  folds 
  and 
  faults 
  is 
  the 
  

   northern 
  continuation 
  of 
  the 
  Appalachian 
  system 
  which 
  extends 
  

   through 
  New 
  Jersey, 
  New 
  York 
  and 
  eastern 
  New 
  England 
  far 
  

   into 
  Canada. 
  The 
  greater 
  part 
  of 
  this 
  area 
  of 
  disturbance 
  is 
  in 
  

  

  *Some 
  of 
  these 
  undulations 
  are 
  described 
  by 
  H. 
  S. 
  Williams, 
  Am. 
  Assoc. 
  Adv. 
  Sci., 
  Proc, 
  voL 
  

   31. 
  1882. 
  

  

  