The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1873-02-22
Coal Its Origin.
tFrom the Curuhll Magazine


A mistaken impression j. somewhat
widely prevalent that. ia the coal fields. We
have the remains of ancient forests in
other words, It Is supposed that wherever
there was a forest i'll prlmcval times there
new exists coal Held If greater pr less
extent ln connection with this view.
;,lsu. THE opinion il entertained that the
forests now III existence Will, IT'D tht pru-
gress NJ time, ana after due geological
changes, become coal beds uf THE future
ages But, although AZ VIZ shall Tres
emily see, the cnal-helds are undoubtedly
due tu the vegetation ot former eras. It is
far from being the case that the urimeyal
forests became converted I'D a general way
INTO coal. Conditions w a peculiar and
~ some extent, exceptional character we're
requisite fur the foundation Of coal fields
If We consider the evidence gwen wv the
coal fields. We shall see what these cUndi
tInns were. The beds or seams of coal
form but small portion III the thickness
ot the great geological group uf strata to
which they fur the most part appertaIn.
This group u called the carboniferuus and
net uncummonly the coal I" but even
where coal j. most abundant, it forms only
has been estimated, Sir Charles Lyell TEN
us, that i'll SputhWales the thickness pf the
CarboniferOus strata amounts. in all. to
between II 900 and 1900 feet lur more
than two miles y Il but the various coal
seams do not, according to Prof. Phillips,
exceed the aggregate l20 feet, w less
than Tooth part of the whole I'LL North
Lancashire the carboniferous strata occupy
a depth Of more than three miles Here.
nv fewer than 50 seams IF coal have been
counted (1l having been exposed TN the
action Of the sea ~ but these seams are no
where more than five feet in thickness,
ana many are but few inches thick
THUS. IL Is evident that the formation of
coal can have been in progress but a short
portion uf the time during which the CAR
buniferuus series Of strata was IN process III
deposition. Throughout by far tile great
er portion Of that time other minerals are
being deposited 1t Il next to be noticed
that under each coal seam a stratum NJ
ancient soil exists, in which thare are
commonly found the roots " ancient trees
while above the coal there il commonly a
layer Of shale Or sandstone. ia which not
unfrequently the trunks of these trees are
found either fallen Or still in their original
position, and only partly converted into
coal. The bark remains. but j. trans
mitted into coal the hollow of the trunk
decaying long before the trunk gave way,
Is represented by cast in sandstone
Thus, If We try to picture To ourselves the
state Of things which existed when such
seam of coal first began tO he covered up
by the next higher deposit, We see that
there must have been trees standing erect
above layer Of vegetable matter. the
roots Of the trees being embedded ia the
soil which forms the deposit next below
the coal The vegetable layers may prob
ably have been two on three times az thick
As the resulting coal seam, and were re-
duced by pressure To their present thick
ness but such layers cannot at any time
have reached the branches Of the forest
trees. Then the process IF deposition be-
gan This can only have happened when
some subsidencs Of the soil had caused II
To be submerged to a greater ur less depth
We can infer from the depth Of the strata
overlying the coal seams, that this state Uf
submergence continued III many cases for
long period of time and il Is equally clear
that the formation of the vegetable LAYERS
themselves have been process occupying
a considerable time, since tall trees grew
before the next submergence tuok place.
50 soon as submergence was complete, the
tall trees perished and began 70 decay.
The tall trunks above the vegetable layer
were broken off and swept away by the
sea The forest itself, probably - called.
was for the most part destroyed II was
the decaying refuse of the forest, inter
miAed with the lower growths, which
formed the coal seams as they now exist.
Among these were the lower parts Of the
trunks Of the ancient forest trees These
became converted like the rest " vegetable
matter into coal