Page:A sketch of the physical structure of Australia.djvu/36

24 probably split up into another maze-like net-work of ridges; or else by descending at some broken point into one of the valleys and undertaking the same almost hopeless task of tracing out one onward track among an infinite number of ravines perpetually subdividing. Higher up the sandstone plateau, when it attains an altitude of nearly 3000 feet above the sea, some of these valleys attain dimensions of still greater grandeur. The following striking description of one of these valleys by Mr. Darwin will give a good idea of their singular aspect and character:—

"In the middle of the day we baited our horses at a little inn called the Weatherboard. The country here is elevated 2800 feet above the sea. About a mile and a half from this place, there is a view exceedingly well worth visiting. By following down a little valley and its tiny rill of water, an immense gulf is unexpectedly seen through the trees which border the pathway, at the depth of perhaps 1500 feet. Walking on a few yards one stands on the brink of a vast precipice, and below is the grand bay or gulf (for I know not what other name to give it), thickly covered with forest. The point of view is situated as if at the head of a bay, the line of cliff diverging on each side, and shewing headland behind headland, as on a bold sea coast. These cliffs are composed of horizontal strata of whitish sandstone; and so absolutely vertical are they, that in many places, a person standing on the edge, and throwing down a stone, can see it strike the trees in the abyss below; so unbroken is the line, that it is said in order to reach the foot of the waterfall, formed by this little stream, it is necessary to go a distance of sixteen miles round. About five miles distant in front, another line of cliff extends, which thus appears completely to encircle the valley; and hence the name of bay is justified, as applied to this grand amphitheatrical depression. If we imagine a winding harbour, with its deep water surrounded by bold cliff-like shores, laid dry, and a forest sprung up on its sandy bottom, we should then have the appearance and structure here exhibited. This kind of view was to me quite novel, and extremely magnificent." They are however equally numerous wherever the formation occurs, even if it be near or below the level of the sea. Sydney harbour and Broken Bay are instances of this, their many long winding arms and multiplicity of small coves and bays, often bordered by precipitous cliffs, are nothing but the gulleys and ravines of this formation, which in