﻿HUDSON 
  RIVER 
  BEDS 
  NEAR 
  ALBANY 
  567 
  

  

  Lapworth, 
  in 
  correlating 
  the 
  Canadian 
  with 
  the 
  British 
  grapto- 
  

   lite 
  shales, 
  transferred 
  his 
  term, 
  Coenograptus 
  gracilis 
  zone, 
  to 
  

   the 
  corresponding 
  Canadian 
  and 
  Normans 
  kill 
  beds. 
  He 
  dis- 
  

   cerned 
  a 
  closely 
  related 
  zone 
  directly 
  above 
  this, 
  which, 
  in 
  his 
  

   opinion, 
  differed 
  by 
  the 
  absence 
  of 
  Coenograptus 
  gra- 
  

   cilis. 
  Ami, 
  however, 
  subsequently 
  also 
  found 
  that 
  graptolite 
  

   in 
  this 
  second 
  zone. 
  The 
  two 
  zones 
  were 
  then 
  termed 
  lower 
  and 
  

   upper 
  Dicellograptus 
  zones 
  (50). 
  But 
  these 
  terms 
  are 
  not 
  fully 
  

   appropriate, 
  because 
  there 
  have 
  been 
  already 
  distinguished 
  two 
  

   Dicellograptus 
  zones 
  in 
  England 
  (those 
  ofD. 
  complanatus 
  

   and 
  D. 
  a 
  n 
  c 
  e 
  p 
  s 
  ), 
  which 
  lie 
  above 
  the 
  zone 
  with 
  Coeno- 
  

   graptus 
  gracilis, 
  and 
  one 
  in 
  Sweden 
  by 
  Tullberg, 
  which 
  

   lies 
  above 
  the 
  beds 
  with 
  Diplograptus 
  pristis 
  and 
  D. 
  

   quadrimucronatus. 
  It 
  would 
  seem 
  more 
  correct 
  to 
  

   designate 
  these 
  American 
  graptolite 
  shales 
  also 
  by 
  their 
  most 
  

   characteristic 
  species, 
  a 
  task 
  which 
  must 
  be 
  postponed 
  till 
  after 
  a 
  

   closer 
  investigation 
  of 
  the 
  vertical 
  distribution 
  of 
  the 
  graptolites 
  

   and 
  the 
  possible 
  more 
  detailed 
  division 
  into 
  graptolite 
  zones 
  of 
  

   the 
  graptolite 
  beds 
  of 
  the 
  entire 
  middle 
  and 
  upper 
  Lower 
  Siluric. 
  

   Meanwhile, 
  and 
  perhaps 
  even 
  then, 
  the 
  term, 
  Normans 
  kill 
  shales, 
  

   may 
  be 
  of 
  good 
  service 
  in 
  designating 
  this 
  graptolite 
  bearing, 
  

   clastic 
  facies 
  of 
  the 
  middle 
  Lower 
  Siluric. 
  

  

  SUMMARY 
  

  

  This 
  paper 
  purports 
  to 
  demonstrate 
  the 
  presence 
  of 
  four 
  zones 
  

   of 
  shales 
  in 
  the 
  "Hudson 
  river 
  shales" 
  of 
  the 
  Hudson 
  valley 
  

   region 
  about 
  Albany. 
  These 
  zones, 
  which 
  extend 
  from 
  n 
  ne 
  to 
  

   s 
  sw 
  consist, 
  going 
  from 
  west 
  to 
  east, 
  of 
  shales 
  containing 
  the 
  

   Lorraine, 
  Utica, 
  middle 
  Trenton 
  and 
  Normans 
  kill 
  graptolite 
  

   faunas. 
  The 
  shales 
  last 
  named 
  include 
  lower 
  Trenton 
  conglomer- 
  

   ate 
  and 
  rest 
  on 
  lower 
  Trenton 
  limestone. 
  This 
  succession 
  of 
  

   zones 
  places 
  the 
  Normans 
  kill 
  graptolite 
  beds, 
  which 
  form 
  the 
  

   mass 
  of 
  the 
  "Hudson 
  river 
  shales" 
  in 
  the 
  Hudson 
  river 
  valley, 
  be- 
  

   tween 
  the 
  middle 
  and 
  lower 
  Trenton 
  and 
  determines, 
  together 
  

   with 
  other 
  facts, 
  the 
  lower 
  Trenton 
  age 
  of 
  these 
  shales. 
  

  

  