The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1899-09-13

| cluded, and the peaty water itself ex-
| ercised preservatiVe effects. The
amount of carbonized plant tissues
gathered in any place depended on the
area and depth of the marsh and on
| the length of time the land maintained
the same relations to sea level. The
crust, however, was unstable. Eleva-
ton and subsistence caused the shore
| lines to retreat or advance with refer
ence to the land and the coal marshes
shifted position from time to time with
in certain limits. When the sea en-
croached, marshes, with all their accu-
mulated stores of carbon, were sub
merged, and the half-formed coal was
buried under beds of shale and sand
stone, which were spread out as sedi-
ments on, the sea bottom. Elevation
of the crust caused the sea to retreat,
and many times it happened that the
conditions OF marsh and coal accumu-
lation were re-established directly over
the location of an old buried swamp.
Thus it is that in the coal measures it
is rot uncommon to find number of
coal seams one oyer the other, and sep
arated by earthly deposits in the form Of
shale or sandstone. Coal was formed
in shallow estuaries, at the mouths of
rivers, as well as in isolated marshes,
and so part of the material forming
some coal seams may have reached it's
resting place as d1iftwood swept down
from the uplands by flooded drainage
streams. Much the greater part of our
American coal, however, seems to- be
the product. of accommodations of vege-
table detritus in the place where the
plants grew.
The Transformation of Plant Re-
mains Into Coal.
Coal, as we now know it, is the re-
--,,I+ ,@F L -
have been taking place in the beds of
vegetable remains ever since they were
buried under marine sediments during
tn remote carboniferous. The material
has been comDacted and consolidated
by pressure. 1t has everywhere under
gone chemical changes similar to those
that rapidly take place when coal is
subjected to destructive distillation in
gas retortS or coke ovens. Gases have
been evolved, and the residue has been
forming new chemical combinations
Changes have taken place more rapidly
in some localities than in others, and
SO all gradationS are found, from the
soft bituminouS coal of the Mississippi
valley, where the changes are compar-
atively slight, to the hard anthracite of
Pennsylvania, which represents almost
the final product of distillation of coal
in place Every step and stage in the
pTOCESSl VI WOO TO all
thraeite may be brought about artific-
tally, in properly cons. ructed retorts,
in comparatively short time. In ma
ture the process has been slow. In
Iowa and Illinois it is not far advanced
even now In the mountains OF Penn
sylvania, where the crushing and fold
ing of the crust was attended by the
conversion of mechanical energy into
heat on large scale, and elsewhere
where volcanic energy has been exerted
in connection with collaborating strata
the dfstillative processes have been
FASTENED, and the outcome is that to
which all the soft GOALS of the world
are slowly tending, nanely, anthracite.
In Rhode Island there is small coal
area in which the process of change
has been carried further than in the
mountains of Pennsylvania. There the
coal has become in part graphite an
thracite, which it is difficult to make
burn at all, and in part IL is graphite,
which it is impossible to use as fuel
Graphite is the final residual product
in the destructive distillation of vege-
table tissues. -
At Kimberley. in South Africa, the
famous diamond mines are operated
in carbonaceous shale, which has suf-
fered profound alteration by reason of
the intrusion Of volcanic rocks in a
melted condition. The carbonaceous