between the great fallen fragments of sandstone, to ascend through the
gorge by which the river Grose joins the Nepean, yet the valley of the
Grose in its upper part, as I saw, forms a magnificent level basin some
miles in width, and is on all sides surrounded by cliffs, the summits
of which are believed to be nowhere less than 3000 feet above the level
of the sea. When cattle are driven into the valley of the Wolgan by a
path (which I descended), partly natural and partly made by the owner
of the land, they cannot escape; for this valley is in every other part
surrounded by perpendicular cliffs, and eight miles lower down, it
contracts from an average width of half a mile, to a mere chasm,
impassable to man or beast. Sir T. Mitchell states that the great
valley of the Cox river with all its branches, contracts, where it
unites with the Nepean, into a gorge 2200 yards in width, and about
1000 feet in depth. Other similar cases might have been added.
The first impression, on seeing the correspondence of the horizontal
strata on each side of these valleys and great amphitheatrical
depressions, is that they have been hollowed out, like other valleys,
by the action of water; but when one reflects on the enormous amount of
stone, which on this view must have been removed through mere gorges or
chasms, one is led to ask whether these spaces may not have subsided.
But considering the form of the irregularly branching valleys, and of
the narrow promontories projecting into them from the platforms, we are
compelled to abandon this notion. To attribute these hollows to the
present alluvial action would be preposterous; nor does the drainage
from the summit-level always fall, as I remarked near the Weatherboard,
into the head of these valleys, but into one side of their bay-like
recesses. Some of the inhabitants remarked to me that they never
viewed one of those bay-like recesses, with the headlands receding on
both hands, without being struck with their resemblance to a bold
sea-coast. This is certainly the case; moreover, on the present coast
of New South Wales, the numerous, fine, widely-branching harbours,
which are generally connected with the sea by a narrow mouth worn
through the sandstone coast-cliffs, varying from one mile in width to a
quarter of a mile, present a likeness, though on a miniature scale, to
the great valleys of the interior. But then immediately occurs the
startling difficulty, why has the sea worn out these great, though
circumscribed depressions on a wide platform, and left mere gorges at
the openings, through which the whole vast amount of triturated matter
must have been carried away? The only light I can throw upon this
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