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offers, again, views which have nothing in common with those already described. The scene is here one of unbroken solitude, silence, and desolation. On the bare earth, covered only here and there with patches of snow in the midst of summer, thousands of prismatic greenstone columns (of eight or ten feet in diameter) he prostrate at the foot of the traveller; columns of gigantic order, chiselled by nature, and raised by her hands to this majestic elevation, where, overthrown and broken into huge fragments, their ends project over chasms 3000 feet in perpendicular depth.
From this table-land, however, of the mountain's summit, the fearful gorges, precipitous cliffs, and inaccessible ridges of its immediate vicinity disappear; while the distant masses of the western hills seem blended or levelled into one undulating valley, intersected by the windings of glittering streams of the valley of the Tamar, and bounded, on the remotest skirt of the horizon, by a finely-drawn chain of mountains.
The course of the chain, resumed at St. Patrick's Head, is found to recede from the sea, and to follow a south-westerly direction for about sixty miles, without presenting any particular features, either in its main or its lateral branches. At the point called Lake Tomb, and in the vicinity of the eastern marshes, it suddenly turns between those two localities, reaches St. Peter's Pass, and casts towards Spring Hill a spur, which separates the Coal River valley from that of the Jordan; and another, which separates the latter from the Clyde, and of which Table Mount is the principal eminence.
The dividing range next proceeds to the northward, where it divides Lake Sorrel from Lake Arthur. On arriving at Dry's Bluff, — a remarkable elevation, resembling in shape a commanding promontory, — it throws back again a spur, which encircles Lake Arthur, and thus flanks the left side of Lake River, opposite to Miller's Bluff.
A glance from Dry's Bluff embraces all the beautiful sinuosities of the valley of the Tamar, with Ben Lomond, Ben Nevis, Mount Barrow, and Mount Arthur in the background; also those of the valley of the Meander, as far as the north coast; and the table land to the south, with the expanded waters of of Great Lake; its vast, verdant, marshy plains, stripped of timber, plentifully intersected by rivers and rivulets, and here and there broken with ravines and elevations.
Between Dry's Bluff and Western Bluff, the chain, in its semicircular bend, sends one spur to the northward, which terminates in Quamby's Bluff; and several to the southward, which divide the lakes from the tributaries of the river Derwent.
At Western Bluff, it casts to the N. E. a long spur, which separates the river Meander from the Mersey, rendering all the country which borders on Port Sorrel and the river Tamar extremely broken and hilly.
Throughout the whole distance from St. Peter's Pass to Western Bluff, the chain averages 3500 feet in height, and exhibits a greenstone crest of an extremely irregular aspect. That crest is almost every where craggy, fractured, and denuded of vegetation; its spurs steep and tortuous in their course, and angular and fantastic; and its innumerable ravines, invariably deep and dry, are strewed with masses of rock of immense dimensions.
The character which the dividing range displays to the southward of Western Bluff is still bolder: its spurs in the vicinity of Lake St. Clair, to the north, north-west, and west, are topped for the most part by more lofty, bare, and cloven summits of quartz rock and sienite, and are divided by darker gullies, the beds of which, furrowed by the torrents in yet deeper trenches, are at times impassable. The greenstone and basaltic spur which divides the Mersey from the Forth, that which separates the Forth from the Lleven, that which spreads into the Hampshire Hills and stretches to Cape Grimm, and, lastly, the one which divides the river Arthur from the tributaries of Macquarie Harbour, all partake of the colossal, rugged, wild, and distorted features which here distinguish the chain.
Below Lake St. Clair there are two more spurs which deserve a notice.
The one which divides King's river and the Gordon, and which is crowned by Frenchman's Cap, displays from its quartzose summit, scenery of Pyrenean character, unequalled elsewhere in Van Diemen's Land. That also, formed of greenstone and basalt, which separates the Derwent from the Huyon, and which terminates with Mount Wellington, constitutes one of the most striking features in the configuration of the south part of the island. From both these spurs, elevated above all the adjacent mountains, may be seen a vast extent of surrounding and far-distant country. Below the first, stretches the whole scrubby and barren tract between Macquarie and Port Davy, a great part of the western coast, and the northern and eastern eminences of the Lake country: at the foot of the latter spur, are seen, on one side the conspicuous peaks of the elevated land about Lake Sorrel, the Great Lake, Lake St. Clair, and Lake Echo, and all the numerous valleys which ultimately resolve themselves into that of the Derwent; on the other, the Coal River valley, Tasman's Peninsula and the borders of the Channel, with Hobart Town in the foreground, and the indented and projecting southern coast in the horizon.
The chain beyond these two spurs bends in a south
easterly direction, still sending forth minor branches; and studding with conical eminences the skirts of Entrecasteaux's Channel and Research Bay, until it dips under the sea, thus terminating its terrestrial course at South Cape.
We have now endeavoured to present the reader with a sketch, upon which, as upon that of an intended picture, the delineation of the geology of the two colonies will be rendered more clear and perspicuous.
Its most prominent and striking features consist partly in the character of the mineral masses which form the dividing range, which are composed of granite, sienite, hyalomicte, protogene, quartz-rock, petrosilex porphyry, serpentinous hornblende and augitic rocks; partly in the character of the sedimentary rocks, of sUiceous, calcareous, argillaceous, aluminous, and bituminous character, which are confined to the eastern and western talus of that range, resting on it either in a vertical, inchned, or horizontal position.
Its main phenomena are referable to epochs of terrestrial revolutions; some relating to periods marked by a partial quiescence, and the deposition of sedimentary rocks; some to perceptible changes in the condition of the organic life inhabiting the sea; some others, again, to catastrophes which swept from the surface of the earth all its animal and vegetable kingdom.
We shall now select for our illustration of the geology of New South Wales and Van Diemen's Land such only of these epochs as we can classify by the incontrovertible evidences of superstructure, or by organic remains; and we shall review them in the stratigraphic order in which they present themselves to our investigation, beginning with those which belong to the remotest epoch.
To this epoch we shall refer all the phenomena connected with the irruption of crystalline rocks amidst the submarine crust of the earth, and by which a tract of land belonging to New South Wales and Van Diemen's Land appears to have been raised, so as to preclude any farther accumulation of marine deposits. This irrupted or upheaved land is composed either of crystalline and unstratified or of stratified rocks. Amongst the former are —
Eurite. Amongst the latter are —
Argillite. This tract, composed of the above specified mineral masses, and which we have distinguished upon the annexed small map by a pink colouring, appears by geological evidences to constitute the most extensive portion of the actual surface of the two colonies.
Its western limits in New South Wales seem to extend far back into the interior of New Holland, as at 160 miles from the present sea-coast such are not to be traced.
Its eastern limits are delineated by bold landmarks, and may be approximately traced by a line