Wessington Springs herald. (Wessington Springs, Aurora County, Dakota [S.D.]) 1883-1891, 1885-11-06
READING FOR THE YOUNG.
THE FORMATION OF COAL.

THE FORMATION OF COAL.
Tho Immense Timc Taken to Bring About
Present lcsults-How the Question OF
Time Is Determined.
According to tho calculations Of
prominent biologists, the stratum OF
earth that in some places is two miles
and . half thick, constituting the car
isonifcrous or coal age, was deposited
twcnty-nine million years ago. You
WILL wonder how such u calculation can
be made. The result is arrived at by
finding out how the different layers, are
deposited. and estimating the larger
ones by the smaller. AS an example.
the same agencies are at work now as
then, Deposits like those of the Dover
Cliffs. England, are being formed at
che bottom of the ocean to-day; and by
noting the ages of time it takes to raise
a given area an inch, by mean v OF
the fass growing coral, we can form
something Of a guess how long it would
take for two and a half miles of solid
covering to form.
During this time, as the name indi-
Gates, the great beds of coal in Penn
! sylvania and other sections were
deposited, and as we sit by q spark
ling coal-tire we are, after all,
watching a wood one-the wood of
t%wenty-nine million years ago. If you
doubt this, grind Il piece of coal down
as thin as possible and place it under a
! a f,inrNco0,,n auhon $hn VroDIv fit,nr
will be plainly seen.
Mineral coal is merely the element
of carbon mixed with other bituminous
substances. In the formation of BIZ
luminous coal there was a loss of three
fourths of wood AMI tve-sixths in that
of anthracite. There was a greater
loss by decomposition, and a reduction
of bulk by pressure from above, and
from this it is assumed that it took
eight feet of leaves and twigs that
dropped from the trees and blew to-
gether, packed closely, to make one
foot of bituminous coal, and twelve
| feet to make Il of anthracite.
To make a bed of coal thirty feet
thick. like the one in Wilkesbarre. the
| bed of vegetable matter that produced
it must nave been three hundred and
sixty feet thick. Imagine the time it
would take for leaves to drop and
accumulate in II solid mass over a great
area as high as the tallest church-spire!
Hence it is that seam or layers of pure
coal are rarely very thick. Often
times the layer is rs thin as a piece of
paper. but the average is about eight
feet. The Pittsburgh seam. Mt the place
| of the same name. is Just this thickness.
and can be seen on the high shores from
the Monongahela River, and traced into
Virginia and Ohio, over an area of two
hundred and twenty-five by one hum
drea miles, and even into Kentucky. 1t
varies also in thickness. as in the Cum
berland basin it is fourteen feet thick,
six at Wheeling, five at Athens, o., and
on the Great Kanawha from two to
three feet.
Coal-heds form much quicker under
water, where the leaves were held in
place and retained their gaseous parts
which would be lost in the atmosphere.
The common peat beds of to-day are
perhaps coal-beds of the future at
least, they resemble in origin the old
! plant-beds. Over one-tenth of Ireland
is covered with peat-beds, some forty
feet deep. In Massachusetts alone,
there are v 100, 0OO, 900 cords of it,
I Trees are often found buried in them,
and in Ireland Il gigantic fossil elk is
found.
You may wonder where all the car
bon came from that seems to be the
prominent ingredient in coal. II is be-
lieved that in the coal nge there was
much more carbon in the atmosphere
than at present, and during this time
it was stored away by the wonderful
plants that were so fitted for the pur-
pose. This. too. purified the air for
the birds and higher forms that came
later.
The curious mineral oil, petroleum..
was formed similarly TO coal by the de-
composition of vegetable or animal re-
mains, either marine or terrestrial,
buried in mud, in time slowly ch.nging
into oil, or some materials, that pro
duce it by distillation: bat OIL, unlike
the coal, is found in the layers of all
ages, from the lower Silurian wells of
Kentucky and Tennessee to the Terri.
airy wells of Southern California.
Like other strata, that OF the coal
age only appears at the surface at GER
tdll pfdCtS-lu lNcu. tue lOuIl HHlnDer
of square miles Of all the productive
coal-tields in the United States is only
125 5000; in Scotland. 1000 square miles:
Ireland, 1,S50,0 DOC, and in England, 3
100000 square miles. Then again, it
is not always represented by coal. 1t
contains stratiiied rocks of all kinds,
sometimes shales. ~sandstones, con-
glomeratcs. But how, you will ask,
were all these layers placed there?
Geology shows us that the age lust
before the coal was n OF submergence
that is, most Of the land was under
water: but later, there was a rising,
and great tracts of swamp-land APP
peared. In them grew trees and vege-
tation totally unlike those of to-day,
the ferns even being trees, and large
ones. too. The vegetation was Won
derfully profuse. Curious tiowerless
! plants called cryptograms were COM
mon "a sort OF ground pine. A Lyco-
podia that lives now, four or five feet
high, in this wonderful time was sixty
or seventy feet high. One of the COM
mOnest trees was tho SirilIori, yvh;oL