The Cheyenne daily leader. [volume] (Cheyenne, Wyo.) 1870-1884, 1882-06-16
White Chalk.

Chalk is such a common thing that it Is
difficult TO think there can be anything
very wonderful about it; but when care
fully studied n examined, few substances
turn out to be more extraordinary. Chalk
is wonderful on account of its forming a
large part of h crust of the earth, and be-
cause it consists of countless fragments of
minute creatures which were once alive
moreover, the n in which the bold
white ellis stand up against the sea, century
after century, is worth considering, as is
also the way in which the long layers of
hints, one over the other, were formed.
Chalk is n very old substance, for the cliffs
have stood by the sea-shore longer than the
oldest history tells of; and when inland,
the white chalk is often found in sinking
deep wells through clay and sand. Geolo-
gists have proved that although most of
the chalk now forms on dry land, high
hills, and bold cliffs, yet it was produced
layer after layer at the bottom of a very
deep sea-, and was gradually lifted up by
the internal forces of the globe TO its pres
ent position. 1t is found in a great many
of the counties of England quite on the
surface of he ground, and in others it is
situated deep down in the earth, being
covered up with other soils. Vast regions
in North and South America, Ireland, Dem
mark, Belgium, Germany, France, Algiers,
and India are covered with the powdery-
looking mineral we call white chalk, and
much of it under the sea, and is OCCASION
ally found out in sinking foundations for
lighthouses. No only does the chalk form
the surface of the ground over n large por-
ton of the earth, but it is also very deep.
A cliff, although 500 or 600 feet high, does
not show all the chalk, for boring proves
that 1t goes down deeper than the level sur
face at its foot. In England, especially in
the southeastern counties, the chalk is
very deep, and extends downwards for
l,2OO feet. The upper part, as is well known,
has many layers of black flints in it, one
over the other, and extending for miles /;
the lower 700 feet of chalk has no flints in
ii, but forms in many foreign countries
high mountains with tall peaks inc precipi-
ccs, very unlike the rounded downs and
sloping valleys in England. 1t was men
toned that some soils were on top of the
chalk in certain places. Now, there is a
capital example of this in London. There
is chalk on the Surrey side of the Thames,
but 1t does not appear on the north side.
When a well is dug on the south side,
chalk is soon come to but in London itself
n dark BIT clay is found, and il is no less
than 800 feet deep. The clay must b. pierre
ed by the boring-machine for rather more
than this depth before chalk is reached.
VI SoNA9t, "a TINS great IllSs Oh cay, uOuDle
the height of st. Paul's, was collected
gradually on top of the chalk, and it was
not done in n day. Many thousands of
years must have elapsed whilst it was being
made, for it was the washings of distant
hills brought down by many streams, like
the clayS which are now forming at the
bottom of lakes. There are all sorts of
wonderful things in this clay, such as skele-
tons of great c~rocOdiles, a~lligators, beavers,
fish, birds, and turtles, masses of decayed
fruits like cOcoanuts and p~ineapples, and
vast quantities of small shells. But the
chalk is under all these, and is therefore
older. If a small piece of chalk is moist
ened and rubbed on a slip of glass, and
placed under n powerful microscope, my
riads of very small things are seen. Some
are fragments of larger things, but the
greater part consists of the tiny skeletons
and shells Of what is called animalcules.
Much of the chalk consists, also, of round
grains, which, when broken down, are found
TO contain other grains arranged in circles
rounda centre. These are all of
very small creatures, which were once alive.
SO small were they, that 10000 of them
placed in n row would not make up an
inch in length. The shapes of the little
shells are very pretty, and they are beauti-
fully marked with dots and lines, so as to
AN'Ht 'N'N iAA'ANHhAiS ohJ'Nto uhuG II ROUu
misCroscupe. Every piece of chalk contains
n vast quantity of these things, and also
grains of what is called carbonate of lime.
By diligent search through the chalk
quarries many ]curiosities have been found,
and the skeletons of flying reptiles, huge
lizards, CrOCOdilcs. and beautiful shells, ana
great quantities OF Sea-urchinS aud star-f.h
may be seen In the British Museum taken
from the chalk. Some of these are very
large, hut the bulk of the chalk all over the
world is made up of very minute things
invisible TO the naked eye. If the chalk
extends for thousands of square miles, and
is 1000 feet thick, what i~ncalculable mil
lions of the remains of minute creatures
there must be in it! The tiny animalcules
lived in the old ocean, aud rs they died in
their hard shells fell TO the bottom, and in
course of ages HI mass of the chalk was
thus formed as a sediment in the deep sea.
1t is impossible to conceive how long this
sediment took to collect, but it is easy to
form an idea how long a small portion of
chalk takes to be removed. Thus, the
island of Thanet is about ten miles long
and five broad, and the chalk is, in round
numbers, 1900 feet thick there are, there
fore, about 42,00O,000,OOO tons weight of it.
Surprising 1000 men and 1000 horses and
carts TO do always what is called a good
days work, it would take them 10000 years
TO remove the chalk, provided it were dug
mp ready for carting. The history of chalk
is, therefore, very wonderful, for it was
gradually deposited in the deep ocean,
being formed of the remains of the small
est sea animalcules and of the skeletons of
the large creatures that died in the water.
After 1900 or more feet of this fine
white sediment were formed, the whole
was lifted up nearly to the surface, and
then n clay wa formed on the top in many
places. The creatures whose remains are
found in the clay are not of the same kind