The Ottawa free trader. [volume] (Ottawa, Ill.) 1843-1916, 1881-05-28
White Chalk.


Chalk is such a common thing that it is diff
ticult to think there can be anything very
wonderful about it; but when carefully stu
died and examined, few substances turn out
to be more extraordinary. Chalk IS wonder
full on account of its forming large part of
the crust of tho EARTH and because it consists
of countless fragments of minute creatures
which were once alive moreover, the manner
In which the bold white cliffs stand up against
the sea, century after century is worth consid-
ering. rs is also the way in which the long
layers of flints, one over the other, were form
ed Chalk is very old substance, for the
cliffs have stood by the seashore longer than
the oldest history tells of; and when inland,
the white chalk is often found IN sinking deep
wells through clay and sand. Biologists 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 al the
bottom Of very deep sea, and was gradually
| lifted up by the internal forces of the globe to
its present position. 1t is found in great
many of the counties OF England quite ON the
surface of the ground, and in others 1t is stu
ated deep down in the earth being covered up
with other soils. Vast regions IN North and
South America, France, Alglers and India are
covered with the powdcry looking mineral we
call white chalk, and much of 1t under the
| SCu, anu 10 o,IuSiohhiiy iohh' ~
foundations for lighthouses. Not only does
the chalk form the surface of the ground over
large portion 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 it goes down deeper than the level surface
at its foot In England, especially in the
southeastern counties the chalk is very deep,
and extends downwards for 200 feet. The
upper part, as is well known, has many layers
of block tints IN it, one over the other, and
extending for miles, the lower 700 feet of
chalk has no tlints in it, but forms in many
foreign countries high mountains with tall
peaks and precipices, very unlike the rounded
downs and sloping valleys IN England. 1t
was mentioned that some soils were on top Of
the chalk in certain places Now, there is q
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 a dark blue
clay is found, and it is no less than 800 feet
deep The clay must be pierced by the boring
machine for rather more than this depth be-
tore chalk is reached. OF course, all this great
mass OF clay, double the height of st. Paul's
was collected gradually on top of the chalk
and it was not done in day Many thou
sands of years must have elapsed whilst it was
being made, tor 1t 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 skeletons Of great croco
diles, alligators, beavers, fish, birds, and tur-
ties, masses OF decayed fruits like cocoanats
and pineapples, and vast quantities Of small
shells. But the chalk is under all these, and
Is therefore older. If small piece Of chalk is
moistened and rubbed on a slip of glass, and
placed under powerful microscope, myriads
of very small things are seen. Some are fiag-
ments 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 grams, which,
when broken down, are found TO contain other
grains arranged IN circles round centre.
These are all remnants of very small creatures
which were once alive. So small were they
that 5000 Of them placed In row would not
make up an inch in length. The shapes of
the little shell are very pretty, and they are
beautifully marked with dots and lines, so as
TO form very interesting objects under good
microscope. Every piece Of chalk contains q
vast quantity of these things, and also grams
of what is called carbonate Of lime.
By dilIgent search through the chalk quar-
RES many curiosities have been found, and
the skeletons Of flying reptiles. huge lizards,
crocodiles and beautiful shells, aud great
quantities Of seaorchins and star fab, may he
seen in the British Museum taken from the
lchalk. Some Of these are very large, but the