420 



NEW YORK STATE MUSEUM 



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. 



r .. i Coal measures 



Carbomterous s . , . ,. 

 « bubcarboniler 



Devonian 



{ Middle Devonian 



Paleozoic <( Silurian 



Ordovician 



Cambrian 



Millstone grit 

 bcarboniferous. Mauch Chunk 

 f f Catskill 



i Upper Devonian., i Chemung 

 I Portage 

 { Hamilton 

 X Marcel lus 



Corniferous J Corniferous* 



' Schoharie 



Oriskany Oriskany 



Lower Helderberg Lower Helderberg 



_ , { Waterlime 



0n0nda S a ISalina 



( Niagara 



Niagara -{ Clinton 



I Medina 



r Hudson 

 i ,i 



I Trenton <; Utica 



{ { Trenton 



i Canadian -5 .* 



^ (Lalciferous 



f Upper Potsdam 



{ Middle Acadian 



I Lower Georgian 



n ver 



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. 



