THE YORKSHIRE COALFIELD 17
yards, and the Thorne Colliery is opening out at a depth
of 916 yards. The thickness of the workable seams varies
from g ft. in the Barnsley bed to 1 ft. 9 in. in the “Cat”
coal.
The special qualities of the coal found in particular locali-
ties have largely influenced the development of the metallur-
gical industries carried on in its neighbourhood. The great
reputation, for instance, of Low Moor iron is said to be
partly attributable to the character of the coal used in its
manufacture. In Sheffield, too, the steel-maker uses by
preference certain seams of coal for his Siemens furnace,
and chooses coke derived from the coal of other seams in
making crucible steel.
Coal has probably been worked and used in Yorkshire
as long as anywhere else in the British Isles. The frequent
occurrence of coal and iron deposits together gave rise in
that area to a remote metallurgical industry, of which
history affords no trace, but which is evidenced to-day by
the presence of furnace slag and coal ashes in the remains of
Roman and pre-Roman operations. There are, however,
records of the working of coal at Silkstone, near Barnsley,
and near Rotherham in the thirteenth century. A field
called Netherhalge which contained a coal mine was leased
by Thomas de Schefeld to Esmond Fitzwilliam in the
fourteenth century. There are numerous historic references
to the working of coal near Sheffield during the sixteenth
and seventeenth centuries. No accurate records of the
extent of working and consumption of coal in Yorkshire
exist prior to 1870; but it is doubtful if, say, in 1850 the
quantity of coal raised in Yorkshire exceeded 3,000,000
tons per annum. The shallow workings were from the
western outcrop, and have extended eastward as mining
engineering became capable of dealing with deep sinking,
But the modern coalfield, though greatly developed in recent
yoy, is really of a respectable age. It has given rise to