NEW YORK STATE MUSEUM 



Devonic system, all the subdivisions comprising this system in 

 western New York being found within the area covered by the 

 map, though the highest, the Chemung sandstones and shales, is 

 represented by only a fraction of its thickness and over a small area. 



The drift sheet or soil mantle on these areas is usually quite 

 thin and rock outcrops are frequent except in the flat region in 

 the northern part of the Attica quadrangle where it is much thicker 

 and rock exposures very rare. 



The Mesodevonic Marcellus and lower Hamilton beds are quite 

 well displayed on the Depew quadrangle in the vicinity of Lancaster, 

 along Cayuga creek and other small streams. 



The gorges and gullies through which the Tonawanda, Ellicott, 

 Cayuga and Cazenovia creeks and their numerous branches flow, 

 show the stratigraphic details of the upper Hamilton, the Genesee 

 and Portage beds in a manner and to an extent perhaps nowhere 

 else found so conveniently accessible for examination and the col- 

 lection of their finely preserved and abundant fossils. 



The geologic formations of which the surface rocks of these 

 quadrangles are composed and which are represented by the various 

 colors on the map, consist of the following, in descending order : 



ERA OR SYSTEM 



Devonic 



PERI03 OR GROUP 



Chautauquan. . 



Senecan, 



Siluric. 



STAGE OR AGE 



Chemung sandstones and shales 

 Wiscoy shale 

 Nunda sandstone 

 Gardeau flags and shales 

 Hatch shales and flags 

 Rhinestreet black shale 

 Cashaqua shale 

 Middlesex black shale 

 West River shale 

 Genundewa limestone 

 Genesee black shale 

 Pyrite in Tully horizon 



Moscow shale 

 Tichenor limestone 

 Ludlowville shale 



Erian ■{ Skaneateles shale 



Cardiff shale 

 Stafford limestone 

 Marcellus black shale 



Ulsterian Onondaga limestone 



Oriskanian. Oriskany sandstone horizon 



Cobleskill limestone 

 <! Bertie waterlime 

 Camillus shale 



