162 
[Assembly 
after it should be placed on roofs, but by its decomposition, it changes 
the texture of the slate.^ 
Many localities were also observed in different parts of this range, at 
which quarries have never been opened, but which would, undoubtedly, 
afford roofing-slate of a superior quality. Others, no doubt, might be 
discovered, should the price of the article justify a further exploration. 
Indeed, the quantity of slate, suitable for roofing, contained in this 
range of mountains and hills, can be estimated only by saying, that it 
is sufficient to supply a nation's wants for ages. 
Siliceous slate is quite common, as a modified form of the slate rocks, 
from Kinderhook via Hudson to Thompson's Landing below Rhinebeck. 
It assumes almost every variety of aspect from a common siliceous slate 
through basanite or touch-stone to hornstone and petrosilex. Good lo- 
calities may be seen two and a half miles S. W. of Hudson, one and a 
half miles S. W. of Clermont, several localities in Germantown, and a 
locality two miles N. W. of Lower Red Hook. 
In consequence of the black colour, and thin films of carbonaceous 
matter, which sometimes traverse it, some persons have been induced to 
dig for coal where there was not the slightest probability of finding it. 
A particular variety of this rock, viz, the basanite, is used as a touch- 
stone by jewellers and others, to test the fineness of gold and silver. 
There is not demand enough for this mineral to justify any exploration 
for it. 
Other modifications of the slate rocks my be applied to use, as whet- 
stones, both fine and coarse. They occur in Stuyvesant, Stockport, 
Greenport, Livingston, Germantown, Clermont, and on Rodgers' island. 
Many stone quarries are worked in the coarser varieties of the slate 
rocks, which are the proper graywacks. The stone is used for build- 
ing, for fences, for basement walls, and a variety of uses. The layers 
are from a few inches to six feet thick, and can be split and dressed as 
easily as granite. Some of the slaty varieties of this rock form fine 
flags, and are extensively used in our cities. A quarry of this kind is 
worked a quarter of a mile east of Lower Red Hook. Many others 
might be opened in this range of graywacke, which skirts the east 
* About half a mile S. E. of Bain's tavern is an old slate quarry. A quarter of a mile north 
of Pulver's Corners, in North-East, roof-slate from the same range, containing cubic cavities, 
is used as a fire stone. This kind of rock, laid edgewise, is generally used for the lining of 
furnaces in that part of the country. 
