HOW CAVES ARE MADE--THE WORK OF AGES.
There remain now to be described but four of the caves ordinarily
frequented by visitors. These are "The Garden Palace," "The Stalagmite
Cave," "The Gem of the West," and "The Fairies' Retreat," with "The
Queen's Diamonds." But, as already intimated, it is impossible to
foretell what visions of loveliness may be disclosed by future
explorations. Quite recently the curator has wormed his way into another
splendid cave of large dimensions and great beauty. An opening of about
eight feet leads to a small chamber 14 feet wide and from four to eight
feet high. The floor is pure and sparkling. There are some very pretty
stalactites and pieces of formation hanging from the roof, with
transparent pipes and straws terminating in little hair-like
projections. From this cave there is a passage 10 inches by 14 inches
high and then 14 inches high by 10 inches wide, extending about 21 feet,
and opening on to a room with a floor of velvet-like coral. As the foot
rests on it the sensation resembles that produced by walking on a new
Brussels carpet, or stepping on a frosted lawn of buffalo grass, which
slightly crunches beneath the feet.
This cavern is about 25 feet by 35 feet, and from 2 feet to 10 feet
high. From it there is a fall of about 20 feet, opening into another
chamber, to the left of which is a pretty fimbriated tray, 10 feet by 12
feet, filled with little knobs of formation, with points so sharp that
any pressure of the hand would cause pain. These nodes and points are
almost as clear and spotless as the drops of a glass chandelier before
they have been converted into fly-walks. Then there is another tray or
basin with looped edges containing crystals which are a little "off
colour;" and yet another, with escalloped border and formation of a
milky hue--that is, pure milky--opaque white, not cerulean blue. This
basin is about 14 feet by 16 feet. The roof immediately over the basin
is like delicate coral. To the right is a sort of illusion representing
solidified water round about black limestone pebbles. This crystal has
been formed by a run of water from a rock, the summit of which is about
20 feet away, and which slopes down from the wall at an angle of about
45 degrees.
The sloping rock is beautifully reticulated and marked by curved lines,
which gradually diminish towards the base, where the formation changes
to nodules and curiously-formed, irregular combinations of the preceding
figures massed together. From the ceiling descend various formations of
cave decoration, some clear as the skin of a Mayfair beauty at her first
ball, others of a delicate fawn colour, and the remainder tinged with
oxide of iron. There is a range from the delicate lily of the valley to
the rough bronze of the muscular navvy, not to speak of the dusky brown
of the unwashed sundowner who arrives at a "station" when "the shades of
night are falling fast," and whose motto is not "Excelsior."
The next chamber is about 14 feet by 12 feet, at the end of a slight
declivity as white as snow. It is in the form of an ordinary retort, and
is succeeded by another chamber of somewhat similar contour, the
principal ornamentation being on the floor. Thence the course is
upwards, and the most attractive formation is from the roof. The
stalactites are in clusters, and for the most part small. Some of them
are like twigs, but clear as a limpid stream. Here also are stalagmites
about nine inches high, formed on the ends of huge rocks. In addition to
these are other smaller stalagmites near to a hole about 14 feet deep,
and on the floor are fossil remains. In this hole are passages
unexplored. Hard by is a pretty "shawl" hanging from the roof, and
beyond it a rock about three feet high, the edge of which is covered
with a fine substance like down, which, when blown upon, flies about
like the winged seeds of thistles. Descending from this cavern, about
10 yards through a narrow passage, there is a steep fall of nearly 10
feet, which leads to a chamber, the roof of which is about 10 feet high.
On the right hand side of this cave are some very white shawl pattern
formations and stalactites, and to the left are fine shawls, clear as
glass, from four to eight feet long, and from 6 to 12 inches deep. Just
beyond is a crisp, velvety floor, like that which characterises a
chamber previously described, but not of the same colour. This floor is
in some parts very red, as though it had been coloured with clay, and
other parts are like glass stained with red ochre. The stalactites are
thin, and formed in all sorts of peculiar shapes. The floor is uncommon,
being of a piebald character, appearing as though buckets of solution of
lime had been cast upon it, in the midst of some large stalactites that
give character to the cave, which is about 40 feet by 40 feet. Passing
on you come to a pretty chamber ornamented with stalactites, composed
mostly of yellow crystal. The cave then runs nobody at present knows
where. There are unexplored chambers all around. This cave is named
after the Government geologist, and is to be known as the Wilkinson
Cave.
Mr. C. S. Wilkinson has contributed some valuable matter to Cave
literature. His account of the Jenolan Caves, written for the
Government, contains several beautiful passages bearing upon the
physical and chemical agencies at work in the formation of limestone
caverns. And here it may be interesting to refer to one or two other
authorities also on the same subject. Dr. Wright, an American scientist,
says, "There can be no doubt that the solvent action of water holding
carbonic acid in solution" is the primary agency concerned in the
formation of limestone caves. "Limestone," he says, "is not soluble in
water until it combines with an additional proportion of carbonic acid,
by which it is transformed into the bicarbonate of lime. In this way the
process of excavation is conducted until communication is established
with running water, by which the mechanical agency of that fluid is made
to assist the chemical. Little niches and recesses, which seem to have
been chiselled out and polished by artificial means, were formed in
this manner; for when these points are strictly examined, a crevice will
be observed at the top or at the back of them, through which water
issued at the time of their formation, but which has been partially
closed by crystals of carbonate of lime or gypsum." Dr. Wright,
referring to the different conditions and different periods of cave
formation, says:--"The sulphate of lime, which is known under the name
of gypsum, plaster of Paris, selenite, alabaster, etc., exerts a much
greater influence in disintegrating rock than the sulphate of soda. The
avenues in which gypsum occurs are perfectly dry, differing in this
respect from those that contain stalactites. When rosettes of alabaster
are formed in the same avenue with stalactites, the water which formed
the latter has for ages ceased to flow, or they are situated far apart,
as the former cannot form in a damp atmosphere."
Mr. Wilkinson also alludes to separate periods of formation in
connection with the Jenolan Caves. He says:--"There appear to have been
two distinct periods during which stalactitic growth formed; one of
comparatively remote age, and very local in character, being chiefly
confined to the caves known as the Lurline and Bone Caves; and another
but recent and still in operation. The older growth is essentially of a
stalactitic type, and the stalactites are remarkably thick, though in
one or two cases a huge stalagmite is to be seen. The newer growth
exhibits every fantastic and beautiful form known, from the thin hollow
reed and transparent veil to the snow-white dome stalagmites, the
crystal-fringed pool, the wave-lined floor, and the crooked-fringed
shapes that are turned in all directions." But there is one passage in
Mr. Wilkinson's account which takes us far beyond the time when the
limestone mountains were formed, and describes a complete circle of
natural transmutation and reproduction, and which may be appropriately
quoted in connection with the cave which bears his name. Here it
is:--"First, the decaying vegetation of some ancient forest is invisibly
distilling the gas known as carbonic acid; then a storm of rain falls,
clearing the air of the noxious gas, and distributing a thousand
streamlets of acid water over the surrounding country, and which, as it
drains off, not only wears the rocks it passes over, but dissolves them
in minute quantities, especially such as contain much lime, and then,
laden with its various compounds, flows off to the distant sea, where
reef corals, lying in fringing banks round the coast, are slowly
absorbing the lime from the water around them, and building the fragile
coatings that protect them during life. Slowly as the land sinks the
coral bank increases in height, for reef corals can only live near the
surface of the water; and soon a considerable thickness has been
obtained; while below the upper zone of live corals lies a vast
charnel-house of dead coral coverings; then comes a change; suitable
temperature, or some other essential condition, fails, killing out all
the corals, and through long ages other deposits accumulate over them,
gradually crushing and consolidating the coral bank into a firm rock. At
last a convulsion of the earth's crust brings it up from the buried
depth in which it lies, leaving it tilted on its edge, but still,
perhaps, below the surface of the ground; rain, frost, and snow slowly
remove what covers it, until it lies exposed again to the sunlight, but
so changed that but for the silent but irresistible testimony of the
fossil forms of which it is composed, it were hard to believe that this
narrow band of hard grey rock was once the huge but fragile coral bank
glistening in the bright waters with a thousand hues. And now the
process is repeated; the decaying vegetation of the surrounding forest
produces the carbonic acid, the rains spread it over the ground, which
is now the most favourable for being dissolved, and the consequence is
that the acid water saturates itself with the limestone rock, and
whenever the least evaporation takes place, has to deposit some of its
dissolved carbonate of lime in one of the many stalactitic forms, before
it can flow off to the sea and distribute its remaining contents to
fresh coral banks. Thus the old coral reef melts away far inland, and
the lime that formed the coatings of its corals is again utilised for
the same purpose. What a simple succession of causes and effects, and
yet before the circle is completed long ages of time have come and
gone; and what a fine example of the balance between the waste and
reproduction that takes place in Nature!" And thus the diurnal motion of
the earth and its annual journey round the solar circle, as well as the
repetitions of history, have impressive geological analogies. How many
hearts have begun to beat--how many have throbbed with passion and
ambition, and waxed cold as an extinct volcano in the years required to
form a small stalactite? How many ages have come and gone since the
Jenolan Caves were coral reefs in the azure sea?