﻿332 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  eastern 
  Helderberg 
  escarpment 
  and 
  since 
  it 
  would 
  be 
  difficult 
  to 
  

   find 
  a 
  locality 
  in 
  New 
  York 
  at 
  which 
  the 
  stratigraphic 
  position 
  

   of 
  a 
  similar 
  thickness 
  of 
  rocks 
  is 
  as 
  clearly 
  shown, 
  and 
  finally 
  

   since 
  it 
  is 
  the 
  typical 
  locality 
  for 
  the 
  Lower 
  Helderberg 
  series 
  it 
  

   seems 
  important 
  that 
  the 
  thickness, 
  lithologic 
  and 
  faunal 
  charac- 
  

   teristics 
  of 
  typical 
  sections 
  of 
  the 
  northern 
  Helderbergs 
  should 
  

   be 
  published. 
  Mather 
  in 
  1843 
  in 
  using 
  the 
  name 
  " 
  Helderberg 
  

   division 
  " 
  for 
  the 
  rocks 
  forming 
  the 
  northern 
  end 
  of 
  the 
  Helder- 
  

   berg 
  mountains, 
  stated 
  that 
  " 
  in 
  consequence 
  of 
  these 
  rocks 
  

   being 
  so 
  well 
  developed 
  on 
  the 
  Helderberg 
  mountains, 
  and 
  their 
  

   forming 
  a 
  natural 
  group, 
  strongly 
  marked 
  in 
  their 
  lithological 
  

   and 
  paleontological 
  characters 
  from 
  the 
  strata 
  lying 
  above 
  and 
  

   below 
  them, 
  the 
  term 
  of 
  Helderberg 
  division 
  is 
  used 
  to 
  designate 
  

   them." 
  - 
  

  

  This 
  division 
  included 
  all 
  the 
  formations 
  found 
  in 
  the 
  

   northern 
  Helderbergs 
  from 
  the 
  top 
  of 
  the 
  Hudson 
  to 
  the 
  base 
  of 
  

   the 
  Marcellus 
  shale. 
  Mather's 
  classification 
  has 
  not 
  been 
  gener- 
  

   ally 
  adopted 
  but 
  the 
  name 
  Helderberg 
  is 
  perpetuated 
  in 
  geolog- 
  

   ical 
  classification 
  by 
  the 
  Lower 
  Helderberg 
  period 
  or 
  series. 
  

  

  The 
  general 
  geology 
  of 
  the 
  Helderberg 
  region 
  has 
  been 
  more 
  

   or 
  less 
  fully 
  described 
  by 
  various 
  geologists. 
  The 
  first 
  work 
  de- 
  

   scribing 
  to 
  any 
  extent 
  the 
  geology 
  of 
  Albany 
  co. 
  is 
  that 
  by 
  

   Eaton 
  and 
  Beck 
  in 
  1820. 
  & 
  At 
  least 
  a 
  third 
  of 
  the 
  work 
  is 
  devoted 
  

   to 
  a 
  discussion 
  of 
  the 
  different 
  varieties 
  of 
  soil 
  and 
  their 
  treat- 
  

   ment 
  and 
  naturally 
  enough 
  the 
  geological 
  portion 
  is 
  very 
  crude. 
  

   "A 
  section 
  of 
  the 
  Helderberg 
  " 
  is 
  given 
  on 
  p. 
  55 
  which 
  was 
  ap- 
  

   parently 
  made 
  farther 
  north 
  than 
  Countryman 
  hill. 
  At 
  the 
  base 
  

   is 
  a 
  " 
  compact 
  limestone 
  consisting 
  of 
  organic 
  relics." 
  This 
  state- 
  

   ment 
  is 
  clearly 
  an 
  error 
  as 
  no 
  limestone 
  occurs 
  in 
  such 
  strati- 
  

   graphical 
  position 
  near 
  the 
  northern 
  part 
  'of 
  the 
  mountains. 
  Next 
  

   is 
  what 
  is 
  called 
  a 
  " 
  water 
  limestone 
  destitute 
  of 
  organic 
  relics 
  " 
  

   capped 
  by 
  a 
  layer 
  of 
  " 
  iron 
  pyrites 
  " 
  which 
  is 
  evidently 
  the 
  water- 
  

   lime. 
  Above 
  this 
  is 
  a 
  " 
  slaty 
  sandlime 
  destitute 
  of 
  organic 
  relics 
  " 
  

   which 
  apparently 
  refers 
  to 
  the 
  Tentaculite 
  limestone, 
  while 
  the 
  

  

  flGeol. 
  of 
  N. 
  Y. 
  pt 
  1, 
  p. 
  325. 
  

  

  £Geol. 
  surv. 
  of 
  the 
  co. 
  of 
  Albany, 
  p. 
  56. 
  

  

  