Square Miles.
United States 220,166 } 420,166
„ Lignites and inferior Coals 200,000 }
British Possessions in North America 2,200
Great Britain 3,000
France 2,000
Belgium 468
Rhenish Prussia and Saarbrück 1,550
Westphalia 400
Bohemia 620
Saxony 66
The Asturias, in Spain 310
Russia 11,000
Islands of the Pacific and Indian Ocean Unknown.
The American continent, then, contains much more extensive coal-fields
than Europe; it possesses very nearly two square miles of coal-fields
for every five miles of its surface; but it must be added that these
immense fields of coal have not, hitherto, been productive in proportion
to their extent. The following Table represents the annual produce of
the collieries of America and Europe:--
Tons.
British Islands (in 1870) 110,431,192
United States 14,593,659
Belgium (in 1870) 13,697,118
France (in 1864) 10,000,000
„ (in 1866) 11,807,142
Prussia (in 1864) 21,197,266
Nassau (in 1864) 2,345,459
Netherlands (in 1864) 24,815
Austria (in 1864) 4,589,014
Spain 500,000
We thus see that the United States holds a secondary place as a
coal-producing country; raising one-eleventh part of the out-put of the
whole of Europe, and about one-eighth part of the quantity produced by
Great Britain.
The Coal-measures of England and Scotland cover a large area; and
attempts have been made to estimate the quantity of fuel they contain.
The estimate made by the Royal Commission on the coal in the United
Kingdom may be considered as the nearest; and, in this Report, lately
published, it is stated that in the ascertained coal-fields of the
United Kingdom there is an aggregate quantity of 146,480,000,000 tons of
coal, which may be reasonably expected to be available for use. In the
coal-field of South Wales, ascertained by actual measurement to attain
the extraordinary thickness of 11,000 feet of Coal-measures, there are
100 different seams of coal, affording an aggregate thickness of 120
feet, mostly in thin beds, but varying from six inches to more than ten
feet. Professor J. Phillips estimates the thickness of the coal-bearing
strata of the north of England at 3,000 feet; but these, in common with
all other coal-fields, contain, along with many beds of the mineral in a
more or less pure state, interstratified beds of sandstones, shales, and
limestone; the real coal-seams, to the number of twenty or thirty, not
exceeding sixty feet in thickness in the aggregate. The Scottish
Coal-measures have a thickness of 3,000 feet, with similar
intercalations of other carboniferous rocks.
[Illustration: Fig. 71.--Contortions of Coal-beds.]
[Illustration: Fig. 72.--Cycas circinalis (living form).]
The coal-basin of Belgium and of the north of France forms a nearly
continuous zone from Liége, Namur, Charleroi, and Mons, to Valenciennes,
Douai, and Béthune. The beds of coal there are from fifty to one hundred
and ten in number, and their thickness varies from ten inches to six
feet. Some coal-fields which are situated beneath the Secondary
formations of the centre and south of France possess beds fewer in
number, but individually thicker and less regularly stratified. The two
basins of the Saône-et-Loire, the principal mines of which are at
Creuzot, Blanzy, Montchanin, and Epinac, only contain ten beds; but some
of these (as at Montchanin) attain 30, 100, and even 130 feet in
thickness. The coal-basin of the Loire is that which contains the
greatest total thickness of coal-beds: the seams there are twenty-five
in number. After those of the North--of the Saône-et-Loire and of the
Loire--the principal basins in France are those of the Allier, where
very important beds are worked at Commentry and Bezenet; the basin of
Brassac, which commences at the confluence of the Allier and the
Alagnon; the basin of the Aveyron, known by the collieries of
Decazeville and Aubin; the basin of the Gard, and of Grand’-Combe.
Besides these principal basins, there are a great many others of
scarcely less importance, which yield annually to France from six to
seven million tons of coal.
The seams of coal are rarely found in the horizontal position in which
their original formation took place. They have been since much crumpled
and distorted, forced into basin-shaped cavities, with minor
undulations, and affected by numerous flexures and other disturbances.
They are frequently found broken up and distorted by faults, and even
folded back on themselves into zigzag forms, as represented in the
engraving (Fig. 71, p. 167), which is a mode of occurrence common in all
the Coal-measures of Somersetshire and in the basins of Belgium and the
north of France. Vertical pits, sunk on coal which has been subjected to
this kind of contortion and disturbance, sometimes traverse the same
beds many times.