﻿HUDSON 
  RIVER 
  BEDS 
  NEAR 
  ALBANY 
  511 
  

  

  and 
  geographic 
  relations 
  of 
  the 
  Hudson 
  river 
  shales 
  and 
  Trenton 
  

   limestone 
  will 
  be 
  discussed 
  more 
  fully 
  at 
  a 
  more 
  opportune 
  occa- 
  

   sion. 
  

  

  R. 
  R. 
  Gurley 
  

  

  Dr 
  R. 
  R. 
  Gurley 
  has, 
  after 
  an 
  exhaustive 
  study 
  of 
  the 
  North 
  

   American 
  graptolites, 
  prepared 
  a 
  list 
  of 
  their 
  vertical 
  range 
  (50) 
  

   and, 
  as 
  a 
  result 
  of 
  his 
  investigations, 
  concluded 
  (p. 
  291) 
  that 
  " 
  the 
  

   vertical 
  range 
  of 
  the 
  American 
  species 
  represents 
  a 
  complete 
  

   parallel 
  to 
  the 
  range 
  in 
  other 
  countries. 
  This 
  parallel 
  is 
  not 
  a 
  

   general 
  one 
  only, 
  but 
  is 
  exceedingly 
  detailed, 
  extending 
  beyond 
  

   the 
  genera 
  down 
  to 
  the 
  species, 
  which 
  in 
  each 
  horizon 
  correspond 
  

   to 
  those 
  of 
  the 
  equivalent 
  European 
  horizon 
  almost 
  without 
  ex- 
  

   ception, 
  although 
  of 
  course 
  not 
  every 
  European 
  species 
  occurs 
  in 
  

   America, 
  or 
  vice 
  versa 
  ". 
  This 
  inference 
  stands 
  in 
  accord 
  with 
  

   Lapworth's 
  conclusion 
  of 
  the 
  parallelism 
  of 
  the 
  graptolite 
  faunas 
  

   and 
  supports 
  his 
  correlation 
  of 
  the 
  Normans 
  kill 
  zone 
  with 
  the 
  

   lower 
  Trenton 
  on 
  the 
  base 
  of 
  such 
  parallelism. 
  Dr 
  Gurley 
  also 
  

   asserts 
  the 
  lower 
  Trenton 
  age 
  of 
  this 
  zone, 
  which 
  he 
  terms 
  the 
  

   Lower 
  Dicellograptus 
  zone. 
  1 
  

  

  T. 
  K. 
  Dale 
  

  

  Shortly 
  after 
  the 
  completion 
  of 
  the 
  present 
  paper 
  a 
  most 
  

   elaborate 
  account 
  of 
  the 
  slate 
  formation 
  in 
  the 
  region 
  to 
  the 
  

   northeast 
  of 
  the 
  investigated 
  territory, 
  by 
  T. 
  Nelson 
  Dale 
  (63) 
  

   came 
  to 
  hand. 
  Mr 
  Dale's 
  views 
  in 
  regard 
  to 
  the 
  age 
  of 
  the 
  Hud- 
  

   son 
  river 
  beds 
  agree 
  in 
  a 
  gratifying 
  manner 
  with 
  the 
  results 
  to 
  

   which 
  the 
  writer 
  was 
  led 
  by, 
  his 
  own 
  observations. 
  In 
  the 
  slate 
  

   belt, 
  which 
  extends 
  northward 
  from 
  the 
  Hoosac 
  river 
  in 
  eastern 
  

   New 
  York 
  and 
  in 
  Vermont 
  for 
  about 
  55 
  miles, 
  the 
  Cambrian 
  

   slates 
  are 
  in 
  some 
  localities 
  followed 
  by 
  Calciferous 
  shales, 
  with 
  

   Calciferous 
  graptolites 
  and 
  thin 
  limestone 
  beds, 
  but 
  in 
  more 
  lo- 
  

   calities 
  they 
  are 
  overlaid 
  by 
  various 
  other 
  Champlainic 
  [Lower 
  

   Siluric] 
  rocks 
  which 
  are 
  described 
  as 
  Hudson 
  grits, 
  Hudson 
  

  

  2 
  The 
  upper 
  Dicellograptus 
  zone 
  is 
  Lapworth's 
  zone 
  without 
  Coeno- 
  

   graptus 
  gracilis, 
  in 
  which, 
  however, 
  subsequently 
  a 
  Coeno- 
  

   graptus 
  lias 
  been 
  found 
  by 
  Ami. 
  and 
  which 
  has 
  no1 
  yet 
  been 
  clearly 
  

  

  differentiated 
  in 
  the 
  Hudson 
  river 
  valley. 
  

  

  