﻿158 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  sils. 
  It 
  may, 
  with 
  the 
  waterlime, 
  be 
  traced 
  through 
  Pennsyl- 
  

   vania 
  and 
  Virginia, 
  but 
  is 
  very 
  thin 
  and 
  not 
  found 
  everywhere, 
  

   having 
  been 
  deposited 
  locally 
  in 
  areas 
  of 
  no 
  great 
  extent. 
  

  

  Life 
  of 
  the 
  Upper 
  Silurian 
  

  

  There 
  is 
  no 
  radical 
  difference 
  between 
  the 
  general 
  character 
  

   of 
  the 
  fossil 
  remains 
  of 
  this 
  system, 
  and 
  those 
  of 
  the 
  Lower 
  

   Silurian, 
  but 
  of 
  several 
  thousand 
  species 
  found 
  in 
  the 
  Upper 
  

   Silurian, 
  only 
  a 
  few 
  occur 
  also 
  in 
  the 
  Lower 
  Silurian, 
  and 
  the 
  

   animal 
  forms 
  are 
  nearly 
  all 
  marine. 
  Sea 
  weeds 
  were 
  very 
  abun- 
  

   dant 
  and 
  a 
  few 
  land 
  plants, 
  similar 
  to 
  equisetae, 
  occur. 
  

  

  DEVONIAN 
  SYSTEM 
  

  

  This 
  system 
  takes 
  its 
  name 
  from 
  Devonshire 
  in 
  England 
  where 
  

   Its 
  rocks 
  were 
  studied 
  by 
  Sir 
  Roderick 
  Murchison. 
  

  

  The 
  Devonian 
  was 
  the 
  age 
  of 
  fishes, 
  since 
  fishes 
  were 
  the 
  pre- 
  

   vailing 
  type. 
  America 
  has 
  probably 
  the 
  most 
  complete 
  series 
  

   know^n 
  of 
  the 
  Devonian 
  rocks 
  but 
  they 
  have 
  a 
  comparatively 
  

   limited 
  extent. 
  The 
  Devonian 
  rocks 
  contain 
  much 
  carbon 
  in 
  the 
  

   form 
  of 
  bituminous 
  shales 
  and 
  it 
  has 
  been 
  suggested 
  that 
  there 
  

   may 
  be 
  more 
  carbon 
  in 
  the 
  Devonian 
  than 
  the 
  Carboniferous. 
  

   These 
  rocks 
  are 
  well 
  developed 
  in 
  New 
  York 
  but 
  the 
  vertebrate 
  

   life 
  of 
  the 
  system 
  is 
  better 
  shown 
  in 
  other 
  states. 
  

  

  System 
  

  

  Devonian 
  

  

  Group 
  

   Chemung 
  

  

  Portage 
  

  

  Hainilton 
  

  

  Corniferous 
  

  

  Qriskanj 
  

  

  Stage 
  

  

  j 
  Gardeau 
  shales 
  

   ( 
  Cashaqua 
  " 
  

   r 
  Genesee 
  " 
  

  

  Tully 
  limestone 
  

  

  Moscow 
  shale 
  

   I 
  Encrinal 
  limestone 
  

  

  Ludlow 
  villa 
  shale 
  

   L 
  Mareelhis 
  " 
  

   ( 
  Corniferous 
  limestone 
  

   •< 
  Onondaga 
  " 
  

  

  f 
  Schoharie 
  grit 
  

   i 
  Cauda 
  Galli 
  grit 
  

   ( 
  Orjskanj 
  sandstop^ 
  

  

  