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