﻿STRATIGRAPHIC 
  GEOLOGY 
  OF 
  THE 
  EASTERN 
  HELDERBERGS 
  333 
  

  

  Pentamerus, 
  Shaly 
  and 
  Becraft 
  limestones 
  were 
  apparently 
  over- 
  

   looked 
  since 
  the 
  succeeding 
  and 
  highest 
  division 
  is 
  described 
  as 
  

   a 
  " 
  porous 
  sandstone 
  containing 
  organic 
  relics 
  " 
  which 
  judging 
  

   from 
  the 
  statement 
  that 
  " 
  the 
  best 
  locality 
  of 
  this 
  rock 
  is 
  in 
  the 
  

   town 
  of 
  Berne 
  on 
  the 
  height 
  of 
  the 
  Helderberg 
  " 
  a 
  is 
  undoubtedly 
  

   the 
  Oriskany 
  sandstone. 
  

  

  Next 
  in 
  order 
  is 
  the 
  report 
  of 
  Mather 
  in 
  1843 
  describing 
  the 
  

   geology 
  of 
  the 
  first 
  geological 
  district 
  of 
  New 
  York, 
  6 
  while 
  Em- 
  

   mons 
  in 
  1846 
  added 
  materially 
  to 
  the 
  knowledge 
  of 
  the 
  geology 
  

   of 
  that 
  region. 
  

  

  In 
  1859 
  Prof. 
  Hall 
  enumerated 
  the 
  formations 
  " 
  comprising 
  the 
  

   Helderberg 
  mountains 
  proper 
  in 
  Albany 
  county 
  " 
  and 
  proposed 
  

   the 
  names 
  " 
  Lower 
  Helderberg 
  group 
  " 
  composed 
  of 
  the 
  Tentacu- 
  

   lite, 
  Pentamerus, 
  Delthyris 
  shaly, 
  Encrinal 
  and 
  Upper 
  Pentani- 
  

   erus 
  limestones 
  and 
  " 
  Upper 
  Helderberg 
  group 
  " 
  composed 
  of 
  

   the 
  Schoharie 
  grit, 
  Onondaga 
  and 
  Corniferous 
  limestones.^ 
  It 
  

   was 
  stated 
  that 
  "the 
  Lower 
  Helderberg 
  group... 
  has 
  been 
  so 
  

   termed 
  from 
  its 
  very 
  complete 
  development 
  along 
  the 
  base 
  of 
  the 
  

   Helderberg 
  mountains; 
  constituting 
  in 
  this 
  part 
  of 
  New 
  York 
  an 
  

   important 
  fossiliferous 
  group. 
  e 
  

  

  In 
  geological 
  classification 
  the 
  Upper 
  Helderberg 
  has 
  been 
  

   partly 
  superseded 
  by 
  the 
  term 
  Corniferous 
  period 
  and 
  series 
  but 
  

   the 
  name 
  Lower 
  Helderberg 
  series 
  or 
  Helderberg 
  limestones 
  is 
  

   still 
  generally 
  in 
  use. 
  

  

  Mr 
  Darton 
  has 
  discussed 
  recently 
  "the 
  relations 
  of 
  the 
  Helder- 
  

   berg 
  limestones 
  and 
  associated 
  formations 
  in 
  eastern 
  New 
  York 
  " 
  

   and 
  described 
  the 
  geology 
  of 
  Albany 
  co., 
  adding 
  considerably 
  

   to 
  the 
  knowledge 
  of 
  the 
  stratigraphical 
  and 
  structural 
  geology 
  of 
  

   the 
  Helderbergs/ 
  However 
  on 
  account 
  of 
  the 
  absence 
  of 
  any 
  

   detailed 
  section 
  in 
  the 
  above 
  works 
  the 
  authors 
  of 
  the 
  present 
  

   paper 
  decided 
  to 
  describe 
  two 
  typical 
  sections 
  of 
  the 
  eastern 
  flank 
  

  

  a 
  Geol. 
  surv. 
  of 
  the 
  co. 
  of 
  Albany, 
  p. 
  29. 
  A 
  description 
  of 
  the 
  geological 
  divisions 
  men- 
  

   tioned 
  above 
  is 
  given 
  on 
  p. 
  26-30. 
  

   fiGeol. 
  of 
  N. 
  Y. 
  pt 
  1, 
  p. 
  317-53. 
  

   cAgriculture 
  of 
  N. 
  Y. 
  1:153-86. 
  . 
  

   fZGeol. 
  surv. 
  N. 
  Y. 
  Paleontology, 
  vol. 
  3, 
  pt 
  1, 
  p. 
  97. 
  

   elbid, 
  p. 
  33. 
  See 
  also 
  p. 
  33-45. 
  

   /13th 
  An. 
  rept. 
  N. 
  Y. 
  state 
  geol. 
  1894. 
  1:197-261. 
  

  

  