﻿GEOLOGIC 
  FORMATIONS 
  OF 
  NEW 
  YORK 
  143 
  

  

  Middle 
  Cambrian, 
  or 
  Acadian. 
  

  

  The 
  type 
  rocks 
  are 
  the 
  shales 
  and 
  slates 
  of 
  New 
  Brunswick, 
  

   Newfoundland 
  and 
  Braintree, 
  Mass., 
  and 
  correlated 
  with 
  them 
  

   are 
  some 
  limestones 
  in 
  Dutchess 
  county. 
  The 
  characteristic 
  fos- 
  

   sils 
  are 
  the 
  Paradoxides 
  trilobites. 
  

  

  Lower 
  Cambrian, 
  or 
  Georgian. 
  

  

  The 
  type 
  rocks 
  are 
  slates, 
  limestones 
  and 
  the 
  ' 
  red 
  sandrock 
  ' 
  of 
  

   western 
  Vermont; 
  and 
  correlated 
  with 
  them 
  the 
  shales 
  and 
  in- 
  

   terbedded 
  limestones 
  and 
  roofing 
  slates 
  of 
  Washington 
  and 
  Rens- 
  

   selaer 
  counties. 
  The 
  characteristic 
  fossils 
  are 
  the 
  Olenellus 
  trilo- 
  

   bites. 
  

  

  Georgian 
  

  

  The 
  lowest 
  rock 
  is 
  a 
  bedded 
  quartzite, 
  resting 
  upon 
  the 
  Arch- 
  

   aean. 
  This 
  is 
  seen 
  on 
  the 
  flank 
  of 
  Stissing 
  mountain, 
  and 
  be- 
  

   tween 
  Fishkill 
  and 
  Poughquag, 
  in 
  Dutchess 
  county. 
  From 
  here 
  

   its 
  outcrops 
  extend 
  northeasterly 
  through 
  Massachusetts 
  and 
  

   Vermont, 
  where 
  it 
  attains 
  a 
  great 
  thickness. 
  

  

  At 
  Stissing 
  mountain 
  it 
  passes 
  above 
  into 
  a 
  limestone 
  contain- 
  

   ing 
  Lower 
  Cambrian 
  fossils. 
  Above 
  this 
  lies 
  a 
  considerable 
  

   thickness 
  of 
  arenaceous 
  limestone, 
  frequently 
  passing 
  into 
  cal- 
  

   -careous 
  shale, 
  and 
  containing 
  Middle 
  Cambrian 
  fossils. 
  

  

  Near 
  Poughkeepsie 
  an 
  extensive 
  limestone 
  formation 
  contains 
  

   Upper 
  Cambrian 
  fossils. 
  

  

  Northward, 
  in 
  Washington 
  county, 
  the 
  quartzite 
  is 
  represented 
  

   by 
  a 
  great 
  thickness 
  of 
  shales, 
  slates, 
  sandstones 
  and 
  limestones, 
  

   well 
  show^n 
  along 
  a 
  line 
  between 
  Greenwich 
  and 
  Salem, 
  and 
  the 
  

   superjacent 
  limestones 
  of 
  Dutchess 
  county 
  are 
  entirely 
  replaced 
  

   in 
  both 
  Rensselaer 
  and 
  Washington 
  counties 
  by 
  slates, 
  shales 
  and 
  

   sandstones. 
  Mingled 
  fossils 
  of 
  Lower 
  and 
  Middle 
  Cambrian 
  are 
  

   found 
  at 
  Berlin, 
  Rensselaer 
  county. 
  These 
  formations 
  continue 
  

   northeastward 
  into 
  Canada. 
  

  

  The 
  great 
  belt 
  of 
  roofing 
  slate 
  in 
  western 
  Vermont 
  and 
  Wash- 
  

   ington 
  county, 
  belongs 
  to 
  this 
  (Georgian) 
  group. 
  The 
  greatest 
  

   development 
  of 
  this 
  formation 
  is 
  at 
  Georgia, 
  Vt., 
  from 
  which 
  

   place 
  it 
  extends 
  southward 
  Into 
  Washington 
  county, 
  where 
  it 
  

  

  