River Falls journal. [volume] (River Falls, Pierce County, Wis.) 1872-2019, 1880-09-09
FORMATION OF AMERICAN COAL
Origin on the Beds---Cause of Impur-
tiles Volcanic Action.
Moses Zweizig in Christian Weekly

The base of our coal measures is n
rock, called the great conglomerate,
which is chiefly composed of white
water-worn pebbles. Its composition
proves to have been the bed of an
ancient sea, and that great sea ex-
isted in the eastern half of our conti-
nent is fact well known to biologists,
who have traced it from the Rocky
Mountains to the Blue Ridge In this
wide expanse of water the coal depos-
its ofour country were formed beyond
doubt 1t was a wise provision of ma
ture To lay for their base the thick and
strong conglomerate rock, as the VOL
| ence of volcanic action in that early
period was so great that weaker bar
rier would have been broken, and the
coal would have been destroyed by
denudation The 100000 square miles
of American coal are divided by Pro-
fessor Rogers into five great fields, of
which the first, or eastern, includes the
coal deposits of Newfoundland, Nova
Scotia, Cape Breton and New Bruins
wick The second, or Allegheny coal
field, is the largest, and extends from
Pennsylvania and Ohio, southwestern,
into Georgia, and includes the anthrac-
tie fields of Eastern Pennsylvania The
third is small field, known as the
northern, occupying the central part of
Michigan; and the fourth is the cen
trail field, including parts of Illinois, In
diana and Kentucky The fifth or ives
tern field lies west of the Mississippi,
principally in Iowa and Missouri, but
extends into Arkansas.
Besides these well defined fields, we
have further west the uncertain depos-
its of the Black Hills; but us the thick
ness of the American coal measures
regularly decreases from east 10 west,
the seams that may be found on the
eastern slope Of the Rocky Mountains
must be very thin and scarcely work
able. In the east, where the coal for
nation is thicl1est, there are in all about
| fifty seams, but not half of them are of
sufficient thickness to be worked. In
| Nova Scotia only five are of workable
| dimensions, and these produce about
| twenty-five feet of coal. In the anthra-
| cite regions the number Of productive
seams is about twenty-five, and they
average in some sixty feet Of coal, but
their maximum yield is somewhat over
hundred feet. The largest of the
anthracite veins is the Mammoth"
which is thirty feet thick. In the Allie
gheny region the average thickness of
workable seams is about half that of the
anthracite fields, and in the western
fields it is only about ten feet Thus
! the number Of seams and the quantity
of coal decrease from east to west; as
also the thickness of the Intervening
strata of rock The greatest depth of
the coal measures, including these
strata, is 5000 feet.
1t is supposed that coal was formed
during the carboniferous era, when the
earth and the atmosphere were in a
condition to produce an unlimited and
gigantic growth Of vegetation.
That the coal beds had their origin
during this vast vegetable growth Is a
well-attested fact; but the process by
which the carbon and bitumen of that
rank vegetation were concentrated and
solidified is point on which scientists
differ. The fact that there is no sign
of vegetation in pure coal indicates
that the component parts have been
expelled by heat or pressure IN the form
of oil. If accumulated vegetation or
woody fiber had formed coal it would
doubtless be fossihferous. 1t seems
natural, therefore, that the enormous
oil deposits of the carboniferOus era,
resulting not only from resinous vege-
tation, but also from the countless
myriads of marine animals, when &C
cumulated in localities having the re-
quisite conditions, formed beds of coal
Great quantities of this oil were evil
IDENTIFY sealed between rocky strata, and
thus kept from solidfying for want of
exposusure; and from these reservoirs
issue the numerous oil springs of the
present day. Herodotus, more than
1000 years ago, referred to a spring on
one of the Ionian islands, which is still
flowing The Chinese hOtsiny, or wells
of fire, re gaseous petroleum springs,
and are made of much practical SER
vice in evaporating saltwater. There
is n similar spring III Fredonia, \. y,
south of Lake Erie, the gas ofwhich is
used for lighting the town. Genoa and
Parma. in the north of Italy, are sim
ilarly lighted In Cuba petroleum
springs are very numerous; and be-
tween the assures of rocks it had con-
solidated in the form ofbitumen, which
I
thus solidified by exposure to mod
ate heat, it bears strong resemblance
to bituminous COAL but under a higher
temperature the hydrogen and oxygen
are evaporated, leaving a comparative
" pure carbon, resembling anthracite;
and when subjected to an intense heat
the carbon is also yaporized, leaving
only the impurities.
The best anthracite coal contains
about 90 per cent. of carbon which is
rendered gaseous by the ordinary pro-
cess of combustion. From these facts
we may infer that the various kinds of
coal are due to different degrees of heat
to which they are exposed during form
alton The oily camel coal was evil
IDENTIFY formed with little heat, the or
binary bituminOus with more, while
the hard anthracite was subjected to
such degree of heat as left it nearly
n pure carbon.
| Oil being lighter than water, it readily
accumulates on the surface of lakes,
and on long exposure, it forms a sheet
of bitumen or pitch, which III winter is
hard, so that man can walk on it with
safety. There is such Il lake ON the
Island of Trinidad, one of the West
Indies; and similar lakes are known to
exist in other volcanic regions Hence
during the periods ofyegetable and ami
NAL oils, and of extraordinary volcanic
activity, producing, no doubt an abund-
ance of oil directly from mineral
sources. it is reasonable to sup
pose that immense bodies OF
water are covered to a great depth
with plastic coal. The time OF
such formation necessarily correspond
ed with a period of volcanic inactivity.
While forming, the sheet may have
been occasionally sprinkled with a
slight shower of ashes, causing an i'm
purity in the coal, such as slate or bone;
and rent in the sheet, caused by con-
traction, may account for the fact that
the miner sometimes suddenly loses
the vein, and must grope for it through
the rock. When volcanic action re-
vived, the greatest imaginable changes
must have taken place, to account fol
the strata of rock everything the seam
Between some of the seams the STRAIT
um is over 200 feet thick. Showers
of ashes or streams of lava may have
sunk the sheet to the bottom, when
during the next period of inactivity, an
other seam may have been formed. to
ha s,,Lpo aYcrad ~, ike manner lint nor.