OLD RED SANDSTONE. FREESTONE. 233 
2. FLOETZ, OR FLAT ROCKS. 
26T. OLD RED SANDSTONE, or MILLSTONE 
GRIT) is a floetz or flat rock, composed of large grains of 
sand or quartz (76), coloured by oxide (21) of iron, and usually 
cemented together by a kind of clay. 
In several parts of Derbyshire this kind of rock forms 
the uppermost stratum ; and in some places, is known 
to be 120 yards thick. 
What are known by the name of peak millstones are 
formed of millstone grit. They are chiefly obtained from 
quarries near Nether Padley, in Hathersede, Derby- 
shire ; a very inaccessible part of the country, but 
where the stone is of better quality than it can else- 
where be procured. These millstones are made of dif- 
ferent dimensions, from two feet in diameter, and eight 
inches thick, to five feet and half in diameter, and 
seventeen inches thick. 
Some of the beds of millstone grit, which have sphe- 
rical stains in them, of light red colour, are said to be 
infusible ; and are consequently a valuable stone for 
lining the hearths of iron and other furnaces, where an 
intense heat is required. These are c&l\edjirestones 9 
and Roches quarry, near Upper Town, in Ashover, 
Derbyshire, is famous for them. 
The upper beds of this kind of rock are often thin, 
and capable of division, so as to make excellent paving 
stones, QY flags. There is a particular bed of it at Stan- 
ton, in the Peak of Derbyshire, so porous that it is made 
intojiltering stones for the cleansing of turbid water. 
268. THIRD SANDSTONE, GRITSTONE, or 
FREESTONE, is another kind of floetz or flat rock, formed 
of very small agglutinated particles of sand. It is opaque, 
usually of whitish colour, and found in large masses, of va- 
rious degrees of hardness. 
The name of 'freestone has been given to this kind of 
rock, from its capability of being broken or hewn, with 
nearly equal facility, in any direction. Hence, as well 
