196 NEW YORK STATE MUSEUM 



SLATE 



Argillite, clay-slate, or roofing slate, which is marked by the 

 presence of cleavage planes, and can be split into thin plates of 

 uniform thickness, is a characteristic rock in the Hudson river 

 group and the Lower Cambrian or Georgian group. 



Slate suitable for roofing has been found in many localities, 

 and quarries have been opened in Orange, Dutchess, Columbia, 

 Rensselaer and Washington counties. The openings in Orange 

 county have not resulted in productive quarries. In Columbia 

 county quarries were worked many years ago, east of New 

 Lebanon. The Hoosick quarries, in Rensselaer county, were once 

 more extensively worked, and produced a good, black slate. Out- 

 crops of red slate are noted east of the Hudson, from Fishkill 

 and Matteawan northward, but no attempts have been made to 

 open quarries in them. 



The productive slate quarries of the state are in a narrow belt, 

 which runs a north-northeast course through the towns of Salem, 

 Hebron, Granville, Hampton and Whitehall in Washington 

 county. 



This slate belt is divided by the quarrymen into four parallel 

 ranges or 'veins,' which are: East Whitehall red slates; the 

 Mettowee, or North Bend red slate; the purple, green and varie- 

 gated slates of Middle Granville; and the Granville red slates. 

 The latter are close to the Vermont line. Further to the east, 

 but over the state line, in Vermont, is the range of the sea-green 

 slates. < 



The quarry localities are at Shushan, Salem, and Black Creek 

 valley, in the town of Salem, Slateville, in Hebron, Granville, the 

 Penrhyn Slate Company's quarries, Middle Granville, Mettowee 

 or North Bend quarries, and the Hatch Hill quarries in East 

 Whitehall. j 



LIMESTONE AND MAEBLE 



Limestones consist essentially of calcium carbonate. They are, 

 however, often quite impure; and the more common accessory 

 constituents are silica, clay, oxides of iron, magnesia, and bitumi- 



