420 



NEW YORK STATE MUSEUM 



Carbonifer 



Devonian 



Its main elements are of Cambrian, Ordovician, Silurian and 

 Devonian time, with some representation, as indicated above, of 

 the Subcarboniferous series. The divisions are given below in 

 descending order. 



\ Coal measures. . . . Millstone grit 



"1 Subcarboniferous. Mauch Chunk 



f [Catskill 



Upper Devonian., i Chemung 



I Portage 



, r . , ~ . (Hamilton 

 Middle Devonian . J 



( Marcel lus 



Corniferous 5 Corniferous 



^ Schoharie 



Oriskany Oriskany 



\ Lower Helderberg Lower Helderberg- 



I _ (Waterlime 

 Paleozoic <; Silurian j Onondaga jSalina 



( Niagara 



Niagara i Clinton 



I Medina 

 f Hudson river 



j Trenton Utica 



[ Trenton 



r 



Ordovician . • <J 



Canadian ■I^*^ 



(Xalcilerous 



Cambrian 



f Upper Potsd-am 



{ Middle Acadian 



L Lower Georgian 



Of these several elements eight or 10 or more are sandstones. 

 The best characterized sandstones are named below in ascending 

 order. Potsdam, Hudson, in part; Medina, Oriskany, Portage in 

 part; Chemung in part; Catskill, Pocono, Millstone grit. 



Sandstones are the chief representatives of porous rocks and 

 as such are the main repositories of underground waters, fresh 

 or saline, and of petroleum and gas. All the strata named above 

 serve in one or more of these several offices at some point within 

 the limits of the state. 



