1864. | Hout on the Coal Resources of Great Britain. 31 
Over the southern half of the ficld—that:is, south of the Bentley 
fault—a coal-seam no less than 30 feet thick is, or was, spread. It is 
called the “ Dudley 10-yard seam,” and is the thickest in England, if 
not in Britain. North of the fault it is split up into nine separate 
seams, which collectively form 50 feet of coal.* The area of the coal- 
field is 93 square miles, and of the original quantity of 3,000 millions 
of tons of coal, not more than 960 millions remain. The production 
of coal has of late years rapidly increased, and in 1861 it reached 
7,253,750 tons from 580 collieries. Taking the future production at 
eight millions of tons, the coal would last 120 years. 
Colebrook Dale Coal-field—This district is even further advanced 
towards exhaustion than the one we have just considered. The coal 
has been worked here more than a thousand years, for it was found in 
the ruins of Uriconium,} and, with the rich seams of ironstone, has 
laid the foundation of several celebrated iron manufactories. Over 
the larger part of the field both minerals have been already worked 
out, and the only place where they yet remain entire is along the 
eastern edge. 'The miles of country covered by mounds of slag, and 
waste heaps of former mines, bear witness, even to the casual passer- 
by, that the earth has been despoiled of all her treasures. 
The area of the field is 28 square miles. The beds dip eastward, 
and may one day be followed under the Permian and New Red Sand- 
stone ; but there are certain irregularities in the stratification of this 
coal-field, that render it uncertain to what extent the beds of coal 
underlie the newer formations. Only one-third of the original quan- 
tity of workable coal remains, which we may place at 14 millions of 
tons. In 1861 the quantity raised was 829,750 tons, so that twenty 
years hence the coal will in all probability be exhausted. 
Leicestershire Coal-field —This is a small, but rich district, as it 
contains one seam 12 or 14 feet in thickness, and several others of 
value. On the Coleorton, or eastern side, there are several collieries 
which are situated on the Trias, and it was here, at Whitwick colliery, 
that George Stephenson, with that power of observation so remarkable 
in him, first came to the conclusion that the coal-measures dipped 
under the New Red Sandstone, and then demonstrated the fact by 
sinking a shaft to the main coal. 
The area of this field is upwards of 15 square miles, of which a 
part is concealed by newer formations, with an available supply of 
140 millions of tons. The quantity raised in 1861 was 740,000 tons. 
Warwickshire Coal-field.—The position of this coal-field is interest- 
ing from the fact that it forms the farthest prolongation of the Carbo- 
niferous strata towards the south-east of England. It occupies a long 
and narrow strip of country, stretching from near Tamworth to Wyken, 
a distance of 15 miles. The strata dip to the south-west under large 
tracts of the Permian formation, where the coal lies at accessible 
depths, and will greatly prolong the resources of the district. The 
* Mr. J.B. Jukes’ ‘ Memoir on the North Staffordshire Coal-field,’ 2nd edition, 
t Or Wroxeter. Mr. T. Wright states that cinders were discovered under 
several of the hypocausts. 
{ Smiles’ ‘ Life of G Stephenson.’ 
