reach of flood, the box (unnamed) alone occupied it; and, though the branches of these trees might be interwoven together, the one never left its wet and reedy bed, the other never descended from its more elevated position. The same singular distinction marked the acacia pendula, when it ceased to cover the interior plains of light earth, and was succeeded by another shrub of the same species. It continued to the banks of New-Year's Creek, a part of which it thickly lined. To the westward of the creek, another species of acacia was remarked for the first time. Both shrubs, like the blue-gum and the box, mixed their branches together, but the creek formed the line of separation between them. The acacia pendula was not afterwards seen, but that which had taken its place, as it were, was found to cover large tracts of country and to form extensive brushes. Many other peculiarities in the vegetation of the interior are noticed in the body of this work, but I have thought that these more striking ones deserved to be particularly remarked upon.

GEOLOGICAL FEATURES.

If we strike a line to the N.W. from Sydney to Wellington Valley, we shall find that little change takes place in the geological features of the country. The sand-stone of which the first of the barrier ranges is composed, terminates a little beyond Mount York, and at Cox's River is succeeded by grey granite. The secondary ranges to the N.W. of Bathurst, are wholly of that primitive rock; for although there are partial changes of strata between Bathurst and Moulong Plains, granite is undoubtedly the rock upon which the whole are based: but at Moulong Plains, a military station intermediate between Bathurst and Wellington Valley, limestone appears in the bed of a small clear stream, and with little interruption continues to some distance below the last-mentioned place. The accidental discovery of some caves at Moulong Plains, led to the more critical examination of the whole formation, and cavities of considerable size were subsequently found in various parts of it, but more particularly in the neighbourhood of Wellington Valley. The local interest which has of late years been taken in the prosecution of geological investigations, led many gentlemen to examine the contents of these caverns; and among the most forward, Major Mitchell, the Surveyor-General, must justly be considered, to whose indefatigable perseverance the scientific world is already so much indebted.

The caves into which I penetrated, did not present anything particular to my observation; they differed little from caves of a similar description into which I had penetrated in Europe. Large masses of stalactites hung from their roofs, and a corresponding formation encrusted their floors. They comprised various chambers or compartments, the most remote of which terminated at a deep chasm that was full of water. A close examination of these caves has led to the discovery of some organic remains, bones of various animals embedded in a light red soil; but I am not aware that the remains of any extinct species have been found, or that any fossils have been met with in the limestone itself. There can, however, be little doubt but that the same causes operated in depositing these mouldering remains in the caves of Kirkdale and those of Wellington Valley.

About twenty miles below the junction of the Bell with the Macquarie, free-stone supersedes the limestone, but as the country falls rapidly from that point, it soon disappears, and the traveller enters upon a flat country of successive terraces. A schorl rock, of a blue colour and fine grain, composed of tourmaline and quartz, forms the bed of the Macquarie at the Cataract; and, in immediate contact with it, a mass of mica slate of alternate rose, pink, and white, was observed, which must have been covered by the waters of the river when Mr. Oxley descended it.

From the Cataract of the Macquarie, a flat extends to the marshes in which that river exhausts itself. From the midst of this flat Mount Foster and Mount Harris rise, both of which are porphyritic: but as I have been particular in describing these heights in their proper place, any minute notice of them here may be considered unnecessary. We will rather extend our enquiries to those parts of the colony upon which we shall not be called upon to remark in the succeeding pages.

Returning to the coast, we may mark the geological changes in a line to the S.W. of Sydney; and as my object is to extend the information of my readers, I shall notice any particular district on either side of the line I propose to touch upon, which may be worthy of notice. It would appear that the first decided break in the sandstone formation which penetrates into the county of Camden, is at Mittagong Range. It is there traversed by a dike of whinstone, of which that range is wholly composed. The change of soil and of vegetation are equally remarkable at this place; the one being a rich, greasy, chocolate-coloured earth, the other partaking greatly of the intertropical character. In wandering over them, I noticed the wild fig and the cherry-tree, growing to a much larger size than I had seen them in any other part of the colony. Upon their branches, the satin bird, the gangan, and various kinds of pigeons were feeding. Birds unknown to the eastward of the Blue Mountains, were numerous in the valleys; and there was an unusual appearance of freshness and moisture in the vegetation.

These signs of improvement, however, vanish the moment Mittagong range is crossed, and sand-stone again forms the basis of the country to a considerable distance beyond Bong-bong. At a small farm called the Ploughed Ground, it is again traversed by a dike of whinstone, and a rich but isolated spot is thus passed over. With occasional and partial interruption, however, the sand-stone formation continues to an abrupt pass, from which the traveller descends to the county of Argyle. This pass is extremely abrupt, and is covered with glaucus, the low scrub I have noticed as common to the sand-stone formation. A small but lively stream, called Paddy's River, runs at the bottom of this pass, and immediately to the S.W. of it, an open forest country of granite base extends for many miles, on which the eucalyptus manifera is prevalent, and which affords the best grazing tracts in Argyle. At Goulburn Plains, however, a vein of limestone occurs, which is evidently connected with that forming the ShoalHaven Gully, which is perhaps the most remarkable geological feature in the colony of New South Wales. It is a deep chasm of about a quarter of a mile in breadth, and 1200 feet in depth. The country on either side is perfectly level, so much so that the traveller approaches almost to its very brink before he is aware of his being near so singular an abyss. A small rivulet flows through the Gully, and discharges itself into the sea at ShoalHaven; but this river is hardly perceptible, from the summit of the cliffs forming the sides of the Gully, which are of the boldest and most precipitous character. The ground on the summit is full of caves of great depth, but there has been a difficulty in examining them, in consequence of the violent wind that rushes up them, and extinguishes every torch.

The open and grassy forests of Argyle are terminated by another of those abrupt sand-stone passes I have just described, and the traveller again falls considerably from his former level, previously to his entering on Yass Plains, to which this pass is the only inlet.

From Yass Plains the view to the S. and S.W. is over a lofty and broken country: mountains with rounded summits, others with towering peaks, and others again of lengthened form but sharp spine, characterise the various rocks of which they are composed. The ranges decline rapidly from east to west, and while on the one hand the country has all the appearance of increasing height, on the other it sinks to a dead level; nor on the distant horizon to the N. W. is there a hill or an inequality to be seen.

From Yass Plains to the very