The Virginia enterprise., 1909-07-23

One Of Prof. Huxley's most interest
ing lectures was entitled "On a Piece
OF Chalk" Chalk is a species of lime
stone made up mostly of the shells of
minute organisms, which appear to
good advantage only under the micro:
scope. The northern portion of France
and the southern shores of England
are wholly made up of chalk cliffs,
which present very striking appear
ance-the old name for England, Al
bion, being derived from a word signi:
flying this white appearance. It is
found that in the deep sea dredgings
these minute organisms which consti-
trte the chalk formation are still &C.
cumulating, though at a very slow
rate. Chalk is therefore supposed to
be a deep sea formation.
Rocks Of corresponding age in other
portions of the world are known as
cretaceous, the word being derived
from the Latin word creta, signifying
chalk. These formations occupy wide
belt in the states west of the Missouri
river, extending from Texas into Brit
ish America, but there is not very
much true chalk such as we are fa-
miliar with in the schoolroom in this
area. The rocks, however, are made
up of species of shells, which are
very beautiful and preserve still their
iridescent color.
Another interesting locality where
chalk is found is over the hills of Pal
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SUBMITS of mountains further south
in Palestine, and the hill on which
Nazareth is built, being of that age
ami consisting, in considerable part,
of pure chalk.
The chalk formations lie in about
the middle of the geological horizon
ard are several million years old.
Coming down to our own line, we
find the process of limestone forma-
tion still going on with great rapidity
in certain localities. The peninsula
of Florida illustrates this in the most
striking measure. Sea shells are so
abundant all along the east coast of
Florida that they are washed up upon
the shore in windrows, forming indeed
the entire shore line, while as one pro-
ceeds to the interior of the state he
finds successive windrows of shells
that have formerly formed the shore
line, showing how the land has grown
by these slow increments. These
shells as they are rolled by the water
are broken up and much of them
ground into fine powder, when they,
all together, become cemented into a
loose rock. The buildings of that re-
gion-especially the old fort at St.
Augustine-are constructed of this
rock, known as cOquina.
Among the most interesting lime
stone strata of the earlier ages are
the corniferous and the Trenton lime
stone, which appear in special develop
ment in the islands in the western
part of Lake Erie, and in an area
about Cincinnati, though the name
was derived from Trenton, N. Y,
where the rocks were first carefully
studied. The corniferous and Tren-
ton limestones are favorites every.
where for burning lime, while the
solid blocks make the most substantial
building material. The great locks at
the 500 were built of corniferous lime.
stone from Kelley island in Lake
Erie, like Solomons temple, every
stone being fashioned at the quarry
and carried directly to it's place in the
great structure, many hundred miles
away.
This limestone is also sought for
very widely for the flux in smelling
iron, it's freedom from impurities Civ
ing it special value.
The extent of these deposits over
the United States is very surprising.
While they appear at the surface at
comparatively few places, they are
penetrated by deep drill holes almost
everywhere in the Mississippi basin,
and in the Hudson river and Mohawk
valleys.
From what we have already said of
the origin of chalk and of the penin-
sula of Florida, it is easy to see that
this extensive limestone stratum over
the Mississippi valley implies in early
geological ages an equally extensive
expanse of ocean, which was slowly
filling up with the sediment in some
places, but with sea shells in others.
The amount of limestone in the
world is enormous, being sufficient to
make stratum hundreds of feet thick
over almost the whole habitable world,
In this there is brought to light a
method of nature to clear the atmos.
phere of impurities which is very in.
teresting. Lime itself, as mineral, is
a very different substance from the
limestone with which we are familiar
Limestone, as we ordinarily know it,
is carbonate Of lime; that is, an ele.
ment of lime is united to one unit of
carbon and two Of oxygen, which
forms the deadly poison known as car.
| bonic acid gas. All the limestone in
the world, therefore, represents such
an amount of carbonic acid gas with
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