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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 

 known 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 



Hamilton 



Corniferous 

 Oriskany 



Stage 



Gardeau shales 



Cashaqua " 

 r Genesee " 

 I Tully limestone 

 ! Moscow shale 

 ' Encrinal limestone 



Ludlowville shale 

 .Marcellus " 



Corniferous limestone 



Onondaga " 



' Schoharie grit 

 ( Cauda Galli grit 

 ( Oriskany sandstone 



