Thomas County cat. [volume] (Colby, Kan.) 1885-1891, 1885-10-22
THE FORMATION OF COAL.

Present ReSults-HOw the Question of
Time Is Determined.
According to the calculations of
prominent biologists, the stratum of
earth that in some places is two miles
and half thick, constituting the car
boniferous or coal age, was deposited
twenty-nine million years ago. You
will wonder how such calculation can
be made. The result is arrived at by
find ne out hoU 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
the bottom of the ocean to-day; and by
noting the ages of time it takes to raise
q given area an inch, by mean seven of
the fast growing coral. we can form
something of a guess how long it would
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 spark
ling coalfire we are, after all.
watching wood one-the wood of
Twenty-Five million years ago. If you
doubt this, grind piece OF coal down
as thin as possible and place it under a
microscope. when the woody fiber
will be plainly seen.
Mineral coal is merely the element
Of carbon mixed with other bituminous
,hct tn khn IS 4;
luminous coal there was loss of three
fourths of wood and five-siXths in that
of anthracite. There was 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 kituminOuS coal. and twelve
feet to make one of anthracite.
To make bed of coal thirty feet
thick. like the one in Wilkesbarre. the
bed of vegetable matter that produced
sixty feet thick. Imagine the time it
would take for leaves to drop and
accumulate in a solid mass over great
area as high as the talleSt church-spire!
Hence it is that seams or layers Of pure
coal are rarely very thick. Often
times the layer is as thin as a piece of
paper but the average is about eight
feet. The Pittsburgh seam. at 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 hun
drea miles, and even into Il entucky. 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-beds 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 reat- beds of to-day are
perhaps coal-beds of the future-at
least. thev 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 over 120. 100000 cords of it.
Trees are often found buried in them.
and in Ireland a 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 age 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 changing
into oil, or some materials that pro-
duce it BY Installations: but oil. unlike
the coal, is found in the layers of all
ages. from the lower Silurian wells of
Kentucky and Tennessee to the Terti-
arv wells of Southern California.
Like other strata, that of the coal
age only appears at the surface at GER
tain places-in fact. the total number
of square miles of all the productive
coal-fields in the United States is only
125. 1000: in Scotland, 1000 square miles;
Ireland, $500 and in England. q
100000 square miles. Then again, it
is not always represented BY coal. 1t
contains stratified rocks of all kinds,
sometimes shales, sandstones. con-
glomerates. But how, you will ask,
were all these layers placed there?
Geology shows US that the age just
before the coal was one of submergence
that is. most of the land was under
water: but later, there was rising,
and great tracts of swamp-land APP
peared. In them grew trees and vege-
tstion totally unlike those of to-day,
the ferns even being trees. and large
ones. too. The vegetation was won
derfully profuse. Curious flowerless
plants called cryptograms were COM
mona 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 the Sigiliaria. which
grew to height of sixty or seventy
feet also, and then branched out with
long. narrow leaves, the trunk being
covered with curious scales. Th&y are