ANTHRACITE 551 same description would apply to the general decrease of carbon and increase of volatile matter in these coal beds from east to west. There is a gradual decrease also in the dimen- sions of the beds in the same direction. The same gradual change from hard anthracite to semi-anthracite and bituminous is as marked a feature in the South Wales (English) coal fields as in the Pennsylvania coal fields. The general fea- tures and fractures of hard anthracite are pecu- liar and noticeable to the common observer. They are massive, hard, dense, amorphous or conchoidal in fracture, with fine, sharp edges when bro- ken, and a rich satin or an iron-black sub-metal- lic lustre. With some local exceptions, the soft- er varieties, both red and white-ash, are less mas- sive, hard, and dense, more regular and cubical in fracture, and, exclu- sive of the upper red-ash beds, less rich and lus- trous. The prominent anthracite fields of the world are those of Penn- sylvania and South Wales, which produce nine tenths of the quantity used. The developed coal fields of the world em- brace an area of about 350,000 sq. m., of which over 300,000 are in the United States, exclusive of lignite. (See COAL.) About 2,000 sq. m. of this entire area contain an- thracite, of which half is in the United States, in- cluding the somewhat doubtful New England coal fields. The entire coal production of the world in 1871 was be- tween 225 and 250 mil- lion tons, of which Eng- land produced 110 mil- lions and the United States 41 millions. About 20 millions of the entire amount was anthracite, of which 15 million tons were produced in Penn- sylvania, and the remain- der in South Wales, France, and other coun- tries. The South Wales coal field lies on the northwest of the Bristol channel, extending from St. Bride's bay in the east to Pontypool " f
in the west, a distance of 90 m., with a maxi-
mum breadth of 60 m. Its mean breadth is
less than 20 m., presenting an area of about
1,500 sq. m., of which only 1,000 contain work-
able coal beds. It is divided by an axis parallel
to its strike, and divided also into numerous
intermediate basins, while the measures undu-
late both from E. to W. and from N. to S. The
deepest part of the field is supposed to be 8,000
ft. Most of the mining has been done by
"drifts," and but few shafts had been sunk to
any great depth up to 1864. Twenty-three
workable seams exist in the principal basins,
averaging altogether 92. ft. of coal. Of these,
12 are from 3 to 9 ft. thick, and 11 from 18 in.
to 3 ft. Besides these there are numerous
smaller seams from 6 to 18 in. thick. On the
N. side of the field the coal is anthracite in
character, and resembles the anthracites of
Pennsylvania, though generally containing more
hydrogen or volatile matter ; on the E. or N. E.
the coal is semi-bituminous, and is used exten-
sively, both raw and coked, in the blast furna-
ces of the region. On the S. side the coal is of
a bituminous character. The change from an-
thracite to semi-bituminous and bituminous is
gradual, and much the same in its metamorphio
phases as we find existing in the coal fields of
Pennsylvania. There are 16 thin seams of iron-
stone interstratified with the coal ; the general
yield of this ore is not over 30 per cent, of
metal in the furnace. The coal production of
South Wales hi 1854 was 8,550,270 tons ; of this
amount only 1,000,000 tons was anthracite,
the total being the products of 245 collieries.
The anthracites of Pennsylvania exist in four
parallel coal fields, in the counties of Schuyl-
kill, Carbon, Columbia, Northumberland, and
Luzerne, embracing an area of 470 sq. m.
Within these fields numerous parallel basins or
synclinal troughs are formed by the peculiar
undulations of the strata, which dip at every
angle from horizontal to perpendicular. Fig. 2
represents the general grouping of the principal
basins of the southern Pennsylvania anthracite
field, and the eastern part of the middle field,
without reference to local peculiarities and
abrupt dips.
PENNSYLVANIA ANTHRACITE FIELDS.
"Wyoming or Northern Coal Field 198 sq. m.
Lackawanna Region 100 sq. m.
Wyoming Region 98 "
Middle or Second Coal Field 91 "
Shamokin Region 50 "
Mahanoy Region 41 "
Lehigh Coal Field 87 "
Hazleton Basin 10 "
Beaver Meadow 8 "
Big and Little Black Creek 9 "
Lower Black Creek 5 "
Green Mountain and other small
basins 5 "
Southern or Schuylkill Coal Field 146 "
Lehigh Region (E. extremity) 16 "
Pottsville Lykens Valley Region. . . 99 "
Middle Region (semi-anthracite). .. 16 "
Dauphin Region (semi-bituminous) 15 "
Total 470 "
Coal was discovered in the Wyoming valley
soon after its settlement, but the first authentic
