The McArthur enquirer. (M'arthur, Vinton County, Ohio) 1873-1884, 1873-01-22
THE COAL FIELDS.
From the Cornhill Magazine.


other words, it is supposed that
wherever there was a forest in
primeval times there now exists
a coal-feld of greater or less
extent. In connection with
this view, also, the opinion is
entertained that the forests
now in existence will, in the
process of time, and after due
geological changes, become the
coal-beds Of future ages. But,
although, as we shall presently
see, the coal-felds are undoubt-
edly due to the vegetation Of
lfpmer eras, it is far from being
the case that the primeval for
ests became converted in a
general way into coal. Condi-
tons Of a peculiar, and to some
extent exceptional character
were requisite for the forma-
ton of coal fields. If we con-
slider the evidence given by the
coal-felds themselves, we shall
see what these conditions were
The beds or seams of coal form
but a small portion of the thick,
ness Of the great geological
group of strata to which they
for the most part appertain
This group is called the car.
boniferous, and not uncom.
monty "the COAL" but ever
where coal is the most abund
ant it forms only a minute par
Of the whole mass. Thus i
has been estimated, Sir Charles
Lyell tells us, that in Soutl
Wales the thickness of th'
carboniferous strata amounts il
all to between II, 900 and II,
900 feet (Or more than tw'
miles), "but the various Goa
seams do not" according t.
Professor Phillips, "exceed il
the aggregate l2O feet" OR les
than one-hundreth part of tn
whole. In North Lancashir
the carboniferous strata occup
3 a depth of more than thre
miles. Here, no fewer tina
E eighty seam Of coal have bee
! counted (seventy-one havin
= been exposed by the action
the sea); but these seams ar
nowhere more than five feet i
; thickness, and many are but
: few inches thick. Thus, it
evident that the formation
coal can have been in progres
$ but a short portion of the tim
during which the carboniferou
series Of strata was in process
: Of deposition, Throughout b
far the greater portion Of thc
time other minerals were bein
deposited. 1t is next to be NJ
ticed that under each coal seal
# a stratum of ancient soil exist
I in which there are commonl
; found the roots of ancient tree
y while above the coal there
: commonly a layer Of shale
!. sandstone, in which not untrC
!: !, quently the trunks Of thos
!. trees are found either fallen
still in their original position
and only partially converte
into coal. The bark remain
+ but it is transmitted into Goa
J, the hollow of the trunk, deca,
y caying long before the trun
j; gave way, is represented by
Q. cast in sandstone. Thus, if "
n try to picture to ourselves Il
. state of things which existt
S when such a seam Of coal fir
began to be covered up by Il
: next higher deposit, we ST
y that there must have been tre'
" standing erect above a layer
8 vegetable matter, the roots
y the trees being imbedded in Il
sr soil which forms the depof
Us Us next below the coal. The We
e etable layers may probably ha'
+, been two or three times
's thick as the resulting coal seal
y and were reduced by pressu
3; to their present thickness, b
3, 3, such layers cannot at any tin
OF have reached to the branch
of the forest trees. Then t
: process of deposition begq
This can only have happen
y when some subsidence of t
soil has caused it to be su
Sc merged to a greater or le
p' depth. We can infer from t
i; depth Of strata overlying t
y coal seams that this state