Geology and Mineralogy of a part of Massachusetts, &c. 17 
seams oblique to the lines of the strata. The seams are 
so numerous, that it is easily obtained for building stone. 
Near the foot of the hill, on the W. side of Washington, 
a little S. E. from the village of Pittsfield, the quartz rock 
is brownish red or brownish; gray, and very remarkable for re- 
sisting the action of fire. Itis ‘used for the walls and hearth 
of the furnace in Lenox, and for the same object was trans- 
ported at great expense to Bennington, Vt. until the same 
rock was discovered near the furnace in that place. A 
similar rock is found in Williamstown. It is not known to 
what this peculiar property is to be attributed, the existence 
of which in quartz rock is the more singular, as this rock 
usually cracks on the application of high heat. Indeed this 
is the common method of getting quartz rock into manage- 
able fragments. I have, however, seen this stone after it 
had sustained the highest heat of the furnace for mouths, 
and found its surface merely glazed by the high tempera- 
ture. 
Near this rock in Washington, but at a greater elevation, 
is a variety of quartz rock, of a whitish aspect and full of 
ragged and irregular cavities. It is pretty extensively 
wrought into millstones, after the manner of the Paris burh- 
- stone. Itis an excellent stone for this use. It corres- 
ponds to the general description of burhstone, and passes 
familiarly under the name of Pittsfieid burhstone. I have 
never seen in it those “siliceous threads’’ which are so com- 
mon in the burhstone of Paris. In its general appearance, 
it is very different from the Paris burhstone, as well as that 
of Georgia. I see no reason why it should not be called 
burhstone, unless this mineral actually belongs to secondary 
rocks. The rock at Washington certainly is surrounded 
on all sides with primitive rocks, and separated from even 
the transitzon rocks by several different strata extending for 
miles to the limit of the primitive formation. A similar va- 
riety of quartz rock is found in Williamstown, and has been 
employed for the same purpose. In Williamstown and 
Bennington rolled masses of quartz occur in large quanti- 
ties. 
Quartz rock is liable to disintegration, especially where it 
lies but just beneath the surface of the earth. In the south 
part of Cheshire, this rock is disintegrated toa great extent, 
and an excelent sand, nearly white, i is found over acres of 
Vou. VII. No. 1. 3 
