﻿336 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Feet 
  

  

  the 
  line 
  of 
  division 
  between 
  the 
  Marcellus 
  and 
  

   Hamilton 
  formations. 
  Again 
  in 
  the 
  Helderberg 
  

   region 
  there 
  is 
  a 
  gradual 
  change 
  in 
  the 
  lithologic 
  

   characters 
  from 
  the 
  Marcellus 
  to 
  the 
  Hamilton, 
  

   and 
  the 
  Marcellus 
  shales 
  have 
  a 
  greater 
  thickness- 
  

   than 
  in 
  central 
  and 
  western 
  New 
  York. 
  It 
  is 
  prob- 
  

   able 
  that 
  the 
  upper 
  part 
  of 
  the 
  hill 
  belongs 
  in 
  the 
  

   Hamilton 
  formation. 
  To 
  the 
  southwest 
  across 
  

   one 
  of 
  the 
  head 
  branches 
  of 
  the 
  Oniskethau 
  creek 
  

   is 
  the 
  highest 
  ridge 
  of 
  the 
  Helderbergs 
  which 
  is 
  

   composed 
  of 
  slightly 
  arenaceous 
  shales 
  contain- 
  

   ing 
  abundant 
  Hamilton 
  fossils. 
  

  

  A 
  12 
  Cliff 
  of 
  massive 
  limestone, 
  the 
  top 
  of 
  which 
  forms 
  100=822 
  

   the 
  upper 
  terrace 
  due 
  to 
  the 
  erosion 
  of 
  the 
  Marcel- 
  

   lus 
  shale. 
  The 
  rock 
  is 
  light 
  gray 
  in 
  color, 
  contains 
  

   in 
  places 
  a 
  considerable 
  amount 
  of 
  chert 
  and 
  is 
  not 
  

   very 
  fossiliferous, 
  most 
  of 
  the 
  species 
  being 
  corals. 
  

   Onondaga 
  limestone. 
  

  

  A 
  11 
  An 
  impure, 
  dark 
  gray 
  limestone 
  which 
  weathers 
  to 
  3=722 
  

   a 
  buff, 
  porous 
  sandrock, 
  shown 
  in 
  places 
  at 
  the 
  

   base 
  of 
  the 
  Onondaga 
  limestone 
  on 
  the 
  cliff 
  south 
  

   of 
  west 
  of 
  the 
  house 
  of 
  Mr 
  K. 
  P. 
  Parrish, 
  where 
  a 
  

   thickness 
  of 
  2' 
  10" 
  was 
  measured. 
  Schoharie 
  grit. 
  

  

  A 
  10 
  Blackish, 
  somewhat 
  arenaceous 
  shales 
  which 
  con- 
  121=719 
  

   tain 
  specimens 
  of 
  Spirophyton 
  cauda-galli 
  (Van.) 
  

   Hall. 
  Esopus 
  shale 
  or 
  Cauda-galli 
  grit. 
  

  

  A 
  9 
  Very 
  dark 
  gray 
  quartzitic 
  sandstone 
  which 
  weath- 
  2=598 
  

   ers 
  to 
  a 
  brownish 
  color 
  and 
  contains 
  abundant 
  fos- 
  

   sils. 
  The 
  upper 
  surface 
  of 
  this 
  sandstone 
  is 
  gener- 
  

   ally 
  covered 
  with 
  markings 
  of 
  Spirophyton 
  cauda- 
  

   galli, 
  and 
  it 
  forms 
  the 
  upper 
  part 
  of 
  the 
  lower 
  ter- 
  

   race. 
  Oriskany 
  sandstone. 
  

  

  A 
  8 
  Ledge 
  of 
  massive, 
  light 
  gray, 
  fossiliferous 
  limestone 
  13=596 
  

   which 
  is 
  well 
  exposed 
  for 
  some 
  distance 
  above 
  the 
  

   highway 
  in 
  the 
  vicinity 
  of 
  the 
  house 
  of 
  Mr 
  K. 
  P. 
  

  

  