The Virginia enterprise., 1909-07-23
BY G. Frederick Wright. A. NJ. IL. ..
STORY OF A LIMESTONE QUARRY.

drawn from the atmosphere, that
should it be all set free, man and most
land animals would find it impossible
to live in it.
Those familiar with burning lime
must have had their attention called
to this fact by the deadly nature of
the gas that settles around the lime
kiln. The burning of lime consists in
applying such a degree of heat that
the carbonic acid gas is expelled from
the limestone, leaving simple form
of lime, which reunites with oxygen
when water is admitted to it. It is
this carbonic acid expelled by heat
which forms the deadly gas of lime
kilns, making it dangerous for chill
dren or animals to lie down and sleep
in close proximity to them.
The forms of sea life which have
contributed to build up the starta of
limestone are exceedingly various.
Among the most interesting are the
corals which have contributed to this
result from the earliest times to the
present. Corals are forms of animal
life which are attached to the sea bot
tom-the animal leaving his shell be-
low him as he dies, and continuing to
live in the upper story thereby grad
ually adding to the solid foundation
from which he started.
In the Pacific ocean and Indian
ocean, and indeed in most tropical re-
gions, corals are still vigorously at
work building up reefs around the
shallow shores of islands and cont:
nents. In the Pacific ocean these reefs
take upon themselves circular shape,
! oftentimes with deep water upon the
| outside, and inclosing a large area Of
shallow water within the circle.
A most interesting theory of Dar-
win and Dana to account for these
| circular reefs or "atols," as they are
called, is that the coral insect began
to build up his structure in the shall
low water surrounding a mountain
peak when the whole bed of the ocean
was slowly sinking. AS the coral
could not endure the deeper water be-
yond, he continued to build up, with
a perpendicular face outward, while
as the ocean bed sank, the inclosure
between the newly started reef and
! the mountain peak would remain free,
because of the sediment washing down
from the mountain, which would in
terfere with the growth of the coral.
Thus it is brought about that in many
cases these circular reefs surround q
body of shallow water, from whose
center mountain peak arises, while
In other cases the settling of the
ocean bed has gone so far that the
mountain peak has disappeared and
there is within simply body of pro-
tected water, which makes an excel.
lent harbor, If there is any entrance
to it.
Among the limestones of great in
terest are the various forms of mar
BILE which have been sought for the
world over for their beauty of color
and their fineness Of texture. These
marbles mostly belong to the very
Oldest geological formations, and ap-
pear In close proximity to granite
rocks, where they have evidently been
subjected to heat and great pressure,
as they were buried deeply in the
earth and transformed or metamor-
phosed into their present shape. The
usual color of marble is white, but
| they are often variegated with almost
every beautiful color derived from
mineral ingredients, especially iron
and copper, giving them a red or
green or yellow cast.
There are also extensive deposits
of lime which are not dependent upon
! the action of animal life, but are
chemically deposited, especially In the
vicinity of springs whose water is
overcharged with carbonate of lime in
solution. AS this water trickles down
from the roofs Of caverns and falls
! upon the bottom, the evaporation
leaves a certain amount, which ar.
ranges Itself in the form of stalactites
at the top and stalagmites at the bot.
tom OF the cavern, the material beina
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somewhat variegated in color and
from objects of great beauty.
But, as already said, the main
| source OF limestone is shells of ami
mails living in the sea- The material
Is brought to them by the rivers which
come down from the continents
charged with carbonate of lime in So
luton, the animals being so consti.
tuted that they can collect this from
the water which surrounds them.
much as the leaves of the trees collect
the carbon from the atmosphere and
convert it into solid chunks of wood.
Thus these forms of animal life
serve double purpose, of cleansing
/ the waters from their impurities. and
OF depositing beneath the ocean bed
the solid rocks which, upon elevation.
become the framework of the conti-
nents, and furnish man with many of
the things most necessary to supply