The daily dispatch. [volume] (Richmond [Va.]) 1850-1884, 1874-07-29
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| Is mercly,a TRANSMITTED VeeetaDleb SOL WHICH
accumulated, not under water, but under
the trees composing primeval forests. These
| forests stood on areas which were subjected
10 repeated changes of level In relation 70
that Of the ocean. It must be understood
that though the ground beneath us is popu.
| larly regarded as the type of everything
steady and mmoyable, this earth Of ours Is
far from deserving the character for stability
| with which it is thus fopdly credited; abso-
lutte rest is all but unknown to it. 1t hap
pens that even ut the present day there are
certain regions, such as those subject to vol
canic disturbances, whose tendencies are
ALWAYS to move upward, like the more as
piring of our youths, while there are others,
such as the coal regions, which are
steadily sinking, like tbose less fortunate
! Youths who have failed in the voyage Of life.
So it was in the olden time. The coal-beds
appear 10 have accumulated on the latter
class of areaS-areas Of depression-geo
/ graphical regions ia which the earth bad a
| tendency to sink below the level Of the ocean.
| Mud and silt had collected upon such areas
until the deposits thus formed reached the
surface level of the water; and then came
what appears 10 have been necessary to the
growth OF the coal plants namely. a bed OF
peculiar gray mud. We do not know why
| that mud came there, or whence it was de-
| rived. That it was very different from Inc
ordinary deposits, the sandstones and sba'es,
which accumulated in the carboniferous
ocean, is shown by the physical properties
| which it sill possesses, and which they
| do not possess-properties which tit 1t for
| the purpose to which it IS now devoted, OF
being manufactured into tire bricks. whence
its common name tire clay. That this gray
mud was the soil preferred by the great ma
iority Of the plants constituting the carbon
ferrous forests is rs obvious as that the OAK
woods Of HerefOrdsbire and the sunny South
will not flourish upon the cold soils OF the
Lancashire uplands. Minute spores, repre-
Senting the seeds Of the plants which after
ward became coal, were tloated to this mud
by wind and water, and finding there suit.
able soil, they terminated, struck roof, ana
soon converted the swampy area into mag
nlficcnt forest. AS the trees grew they shed
successive showers of their microscopic
spores, which often fell in such vast quan.
titles as to constitute an important con-
tribution to the accommodating vegetable
soil; but along with them there fell other
and more bulky objects, such rs might be
expected TO accumulate under seml.tropl-
cal forest. The dead leaves, broken branches,
and prostrated stems alike contributed
share to the decayng vegetable mass. In the
tropical regions Of the present day such ac-
cumulatons become rapidly decomposed
aud pass away in gaseous forms but sucn
does not appear to have been the case IN the
carboniterous age-at least, not IN the same
degree. Even in Lancashire, notWithstand-
inS all the influences tending to diminish the
hulk of the vegetable mass-such as atmo-
spherc ecomposition-chemical changes &C.
curing during the later process OF mlnerail-
Zatlou. and The pressure OF superlmpoScd
rocks prolonged throughout all subsequent
ayes, we have coal seams six or seven feet
in thickness. while they occur in America,
rs. for example, in the o0itic coal-fieid
on the james river, with the surprising
thickness of between thirty and forty feet.
Such Accommodations of vegetable soil rs these
thicknesses of solid coal represent almost eX-
coed comprehension, and must indicate enor-
nous periods OF undiSturbed forest life. But
at length Il change came over the Sylvan
scene: the land sank whether suddenly or
slowly we have no means OF saying. Ihe
numbers of dead fishes found on the roofs
aud upper portions of some Goals seem 10 ln'
dictate a sudden rush of pure water over the
land. followed by the quick destruction OF
the fishes poisoned by the bituminous vege-
table mud in which they found themselves
entangled. In other cases the root OF clean
blue shale, devoid Of all appearance OF
either animal or vegetable remains, and rest
ing Immediately upon dehned surface
oil pure coal, is suggestive OF slower
submergence. allowing time for the destruc-
ton and obliteration of all traces OF growing
vegetation upon its surface. The inland
duration of the submerged stage has varied,
as also has in all probability the kind OF wa
ter under which 1t sank. Whether the coaI
measures are marine or freSh-waler deposits
is still an open question, the answer to which
depends partly upon the nature OF certain
biDalye shells (AnthracosIG) found IN connec-
ton With many of the Goals. 1t is allowed
by the advo ,ates Of the marine hypothesis
that the ganoid fishes so common among the
carboniferous beds are as likely to be fresh
water animals as marine ones, the only
living ganoids with which we are &c.
the sea: but the weight of this argument
is materially reduced by the fact that
in these paleozoic ages all the known fishes
were either .anods or placoids; and no one
doubts for a moment that the great mass,
even of the former, must have been marine,
otherwise we obtain the reduch0 al db-
surdxrn that there were no fishes in many OF
the ancient seas. But there remains yet
more conclusive argument in favor OF the
marine hypothesis. Many of the remains OF
fishes found both in the lowermost and ID
the uppermost coal.beds are those OF pla-
coids--ancient sharks, often Of large size,
and of many species. These fishes, which
are quite as abundant in the carboniferous
rocks as are the ganoids, were certainly
marine animals, and indicate in an IT.
refrayabe manner the marine submer-
oence Of some at least Of the coal seams.
But the probabilities of the case sug.
gest the conclusion that the nature OF
the water would vary at different localities.
We frequently rect with long barrow areas
of sandstone ploughing their way through
coal seams which continue their uniform
course right and left of these Interruptions.
We may conclude, with great probability,
that such sudden interruptions to the CONT
nuity OF the vegetable soil represent ancient
creeks or estuaries which ran in among the
forests, and which, doubtless, received their
drainage in the shape Of brooks and rivers.
In such cases, submergence, if not too rapid,
would cause the vegetable soil to be over.
flowed by fresh water-at least over limited
areas-but in other instances the numerous
remains Of sharks imbedded in the coal tell
of the unmistakable proximity of the sea.
The ultimate physical effects Of these TWO
4, 81,