THE EXTERNAL FEATURES OF THE CAVES.
That portion of the limestone dyke in which the caves are found runs six
miles north and south; and the Grand Arch and the Devil's Coach
House--the two principal "day caves"--are formed right through the
mountain, near the centre, in an easterly and westerly direction. On the
one side McEwan's Creek flows towards the Devil's Coach House, and on
the other side is a natural watercourse leading to the Grand Arch, which
is only a few yards distant from it. Bearing in mind how the
watercourses converge towards these two central caves, and with what
force, in times of heavy rain, the floods scour them, a good
understanding may be obtained of the mechanical causes of the enormous
excavations which excite amazement as well as admiration. If a visit be
paid in winter, when the frost is sharp and the ground is "hoar with
rime;" when every bough and every blade of grass is covered with
congealed dew and adorned with forms of crystallisation which rival the
rarest beauties of the caves; when rocks are split and crumbled by
sudden alternations of heat and cold; there will be abundant
illustration of the effect of water and light, and the variation of
temperature in causing geological transformation. Limestone is not
soluble in water without the addition of carbonic acid. An exploration
of the caves, however, shows that the mountains are not composed
entirely of limestone, but that other substances constitute part of
their bulk. The principal causes of the formation of the "day caves,"
the Grand Arch and the Devil's Coach House, are the mechanical action of
water and the variation of temperature. As regards the interior caves,
where night reigns supreme, chemical combination has played a more
important part. But the effect of water power is everywhere observable
in graceful contours, caused by continuous motion, or in stony
efflorescence, produced by intermittent humidity or dryness of the
atmosphere. The action of the former is the more marked and striking,
the latter more elaborate, and microscopically beautiful. The
hygrometric condition of the caves is recorded in lovely forms, which
lend enchantment to ornate bowers, sparkling grottoes, and fairy cities.
[Illustration: THE GRAND ARCH ENTRANCE.]
[Illustration: THE GRAND ARCH--LOOKING EAST.]
THE GRAND ARCH.
The Grand Arch runs east and west, and is about 150 yards in length, 60
feet high, and 70 feet wide at its western end. The eastern end is 80
feet high, and about 200 feet wide. Its proportions and outline are
gloomily impressive, and rather awe-inspiring. It is like the portico to
some great castle of Giant Despair. The eastern end is a marvel of
natural architecture, and the wonder is how so spacious a roof can
remain intact under a weight so enormous. The rugged walls are varied by
many peculiar rocky formations. On the northern side is "the Lion,"
shaped in stone so as to form a fair representation of the monarch of
the forest. "The Pulpit" and "the Organ Loft" are suggestive of portions
of some grand old cathedral. Adjacent is "the Bacon Cave," where the
formations represent "sides," like so many flitches in the shop of a dry
salter. The roof is hung with enormous honeycombed masses of limestone,
whose sombre shades deepen to blackness in numerous fissures and
crannies and cavernous spaces. As seen from the floor the roof appears
to be covered with rich bold tracery, engraved by Herculean hands. Near
the basement are huge rocky projections, with deep recesses, which for
ages have been the retreat of rock wallabies. Near the eastern entrance,
lying on the ground, is a gigantic block of limestone, weighing from
1,500 to 2,000 tons, and which at some remote period fell, and tilted
half over. This is evident from the stalactite formation which remains
on it. Ascending the precipitous masses on the south-eastern side of the
eastern entrance over rocks which are, on the upper surface, as smooth
as glazed earthenware, a position is attained from which the magnitude
of the ornaments of the roof can be estimated. It is then perceived that
what, viewed from the floor of the archway, seemed like natural carving
in moderately bold relief, are pendant bodies of matter extending
downwards 10 to 15 feet, and of enormous bulk. Along the walls of the
arch are caves running obliquely into the mountain 10, 15, and 20 feet,
and the bottom of which is thick with wallaby "dust." Out of these caves
are passages which enable the marsupials to pass from one rocky hall to
another until they find a secure refuge in some obscure and sunless
sanctuary. The wallaby dust resembles mosquito powder. Perhaps it would
be equally efficacious. It is not improbable that the floors of these
caves represent a moderate fortune. The explorer sinks over his boot
tops in the fine pulverised matter, which, however, is not odoriferous,
and is void of offence if a handkerchief be used as a respirator. The
presence of this substance, and the oxidisation of its ammonia, probably
account for the saltpetre in the crevices of adjacent rocks, although
not absolutely necessary to the result, because, in the absence of such
accessories, it is an admitted chemical fact that nitrifiable matter is
not commonly absent from limestone. In the Mammoth Cave of Kentucky
saltpetre manufacture was carried on to a great extent by lixiviation
from 1812 to 1814, and during the Civil War a principal factor in the
manufacture of gunpowder was obtained from the same source. Up amongst
the rocks, midway between the floor and the roof of the eastern entrance
to the Grand Arch, in the midst of the wallaby drives, and near to a
haunt of the lyre bird, the present curator of the caves had his
sleeping-place for 20 years. There he strewed his bed of rushes or of
grasses and ferns and mosses; and certainly neither Philip Quarll nor
Robinson Crusoe had ever a more magnificent dormitory.
[Illustration: CAMP CREEK.]
Near to it is a sepulchral-looking place, which, before the Cave House
was erected, was reserved for strong-minded lady visitors, and fenced
off with a tent-pole and a rug. Farther on is a series of rocks, where
bachelors could choose for pillows the softest stones in the arch and
dream of angels. All these historic places are pointed out by way of
contrast to the state of things now existing, and which, perhaps, in
turn will form as great a contrast to the state of things 20 years
hence.
From this part of the archway a much better view of the Pulpit, the
Lion, and the Organ Loft can be obtained than is possible from the
floor. Their massiveness is brought out with great effect. The
stalactites and stalagmites which form the organ pipes taper with
remarkable grace, and are set off by the shadows in the recesses which
vary from twilight grey to the darkness of Erebus. Over all are
ponderous masses of blue limestone, with immense convexities filled with
perpetual gloom. The rocks leading to the caves, the upper part of which
is smooth as glass, owe their polish to their long use by wallabies as a
track to and from their favourite haunts. Here and there may be detected
in the "dust" on the floor the footprint of the native pheasant. There
may also be seen and felt boulders and rugged rocks lying about in
strange disorder.
Leaving the Grand Archway by the eastern end, the excursionist descends,
through a rocky defile interlaced with foliage, into a dry, stony creek,
about which are growing some very rare ferns, as well as some which are
common, but nevertheless beautiful, and also some handsome native
creeping plants. From this point may be seen the pinnacle which rises
over the archway to an altitude of about 500 feet. About 50 yards down
this dry creek, and about 20 yards below the junction of the roads from
the Grand Archway to the Devil's Coach House, is "The Rising of the
Water." Here among the rocks in the bed of the creek the water bursts
out of the ground like a sparkling fountain of considerable volume, and
"gleams and glides" along a romantic dell "with many a silvery
waterbreak." And if it does not "steal by lawns and grassy plots," or
yet by "hazel covers," or "move the sweet forget-me-nots that grow for
happy lovers," it does here and there "loiter round its cresses." Its
banks are so steep that its course cannot be easily followed for any
great distance, but, without much difficulty, it may be traced until it
flows over a rocky ledge into a deep pool, where there is a wire ladder
for the convenience of bathers. Thence it chatters on to the River Cox,
whence it enters the Warragamba, which joins the Nepean a few miles
above Penrith, and about 50 miles below the Pheasant's Nest. It does
not, therefore, enter into the Sydney water supply, but passes through
the Hawkesbury to the ocean.
[Illustration: THE DEVIL'S COACH HOUSE.]