Australia, by far the largest island on the earth's surface, and for extent describable as a continent, lies between 10° 39' and 39° 11½' S. lat., and between 113° 5' and 153° 16' E. long.; having a maximum length, from west to east (from Dirk Hartog Island to Point Arkwright), of about 2400 miles; and a maximum breadth, from north to south (from Cape York to Wilson's Promontory), of 1971 miles; making a total area of 2,954,417 sq. m. (excluding Tasmania, 26,215), about one-fourth less than that of Europe, or nearly twenty-five times that of Great Britain and Ireland. Its nearest distance to England is about 11,000 miles. It is separated from New Guinea by Torres Strait, 90 miles broad, and from Tasmania by Bass Strait, 140 miles wide; on the NW., W., and S., it is washed by the Indian Ocean; and on the E., by the South Pacific.
The name Australia in its present signification was first suggested by Captain Flinders, and adopted by the colony about 1817; but the word was used in Purchas his Pilgrimes (1625) and other old works for the unknown southern continent.
This island-continent is, above all other continents, exceedingly compact, with an almost unbroken outline on the east and west. Parallel with the east coast, at a distance of about 60 miles, stretches for 1200 miles the Great Barrier Reef, offering but one safe opening for ships. The sea encircling Australia is, on the whole, comparatively shallow. At a distance of from 300 to 500 miles, however, on the east, south, and west coast, a depth of 15,000 feet is attained.
The absence of rivers communicating between the coast and the interior is remarkable. The mountains rising to any great elevation are all on the east side; and there is but one great river, the Murray, collecting into itself (by the Darling and other great tributaries) almost the whole western drainage of that eastern range. The few mountains on the west side of the continent feed but a few short intermittent streams, and a large expanse, between a narrow strip of occupied country on the west coast and the overland telegraph line, appears to be but a slightly relieved barren desert. The lack of natural irrigation over this arid area is further aggravated by the enormous evaporation, which for long periods dries up such rivers as it possesses.
Physical Features.—The mountains of Victoria are noticed in the description of its geology. The eastern highlands of Australia, running parallel with the coast for some 1700 miles, now in a series of ranges, and now in a single chain or series of detached hills, are continued into New South Wales by the Warragong, or Australian Alps, where in Mount Townsend (7350 feet) the continent attains its highest elevation. Thence upland valleys merge northward into the Blue Mountains, which, again, send offshoots towards the Liverpool Range, that, sweeping east and west, curve round the southern edge of the Liverpool Plains. The main chain skirting the east of New England, runs north to the frontiers of Queensland, where it branches into an eastern arm, the Macpherson Range; and a western arm, the Herries Range. Inclosing the western valley of the Brisbane River, and sinking northward to the valley of the Burnett, is the Dividing Range of Queensland, from whose west side slope the Darling Downs. To the north of the Brisbane and Condamine rivers, the highlands expand to their greatest breadth, but contract again to the north of the Fitzroy River into a comparatively narrow chain, which sinks into the depression of the valley of the Burdekin. North of this river, uplands, with an average elevation of 2500 feet, again start north, terminating at 17° S. lat. In South Australia, the Mount Lofty Range skirts the east of St Vincent Gulf, and the Flinders Range the east of Spencer Gulf and Lake Torrens.
Almost the whole of this vast region in the SE. of Australia (the eastern part of South Australia, Victoria, New South Wales, and Queensland) is drained by the Murray and its tributaries, whose arterial system has an area of about half a million miles, an area twice as large as the Austrian empire. The Murray, rising in the Australian Alps, flows between Victoria and New South Wales, then through South Australia, discharging, after a course of 2345 miles from the source of the Darling, one of its principal tributaries, into Encounter Bay, in the Indian Ocean, shortly after passing through Lake Alexandrina. On its southern or left bank, it receives all the northern streams from the mountains of Victoria, the principal of which are the Goulburn and Loddon. On its northern or right bank, it absorbs all the south-western rivers from the eastern highlands, the principal being the Murrumbidgee (1350 miles long), which also rises in the Australian Alps and collects the waters of the Lachlan; and farther west, the Darling (1160 miles), which has for its tributaries the Barwan, Culgoa, and Warrego. North of the Murray, the two most important rivers are the Fitzroy and the Burdekin in Queensland. The other rivers to the east of the eastern highlands are short and rapid, unfit for navigation. All those hilly and partially river lands consist of grassy park-like uplands, clothed with scattered thin forests of magnificent trees, for the most part evergreen and vertical-leaved, diversified by bush and heath and scrub; all of excellent pasture, intersected by wide valleys of remarkable fertility well adapted for agriculture.
From the head of the Gulf of Carpentaria stretches a tableland westward along the border of the Gulf and the base of Arnhem Land, then SW. along the coast, pierced by the Flinders River, the deep valley of the Alligator, the Roper, and the Victoria; the latter two navigable for a considerable length, and flowing through fertile lands and picturesque scenery.
Western Australia, towards the coast, is in its northern half crossed by ranges of detached mountains, running mostly east and west, and intersected by the fertile valleys of Ashburton, Gascoyne, and Upper Murchison. A large part of its interior consists of a barren tract of salt or mud steppes, almost destitute of fresh water, and extensively overgrown with dreary thickets. In the south, it is pierced by the Upper Swan River and the Blackwood. On the south coast, from King George's Sound to Spencer Gulf, is neither mountain nor river.
To the north of Spencer Gulf is an area of some 1000 sq. m., set with lakes, 'the Lake District' of Australia; Torrens, straight to the north of Spencer Gulf, over 100 miles long, with Eyre to the north of it and much larger, and Gairdner to the west of it. To the east of Eyre are Lakes Blanche and Gregory; and far to the NW., Lake Amadeus. These dead masses of salt water fluctuate greatly in body as the season is dry or rainy, now sheets of water, and now almost grassy plains, set in the dreariest wide-spreading steppes. A comparatively verdant belt of country lies to the east of this district, and runs to the extreme north, as the axis of Australia, along the telegraph line.
Geology.—So far as is known, Australia would seem to be built up chiefly of Palæozoic and Cainozoic or Tertiary formations, though Mesozoic or Secondary deposits have of late also been laid open in various quarters. In Victoria, the Grampians and Pyrenees (with the Ballarat gold-fields to the south) in the SW., the great Dividing Range, and in the NE. the Warragong or Australian Alps; in New South Wales, the Blue Mountains; and in Queensland, the Dividing Range, all consist principally of Silurian strata, broken in upon, however, by intrusive granite, syenite, &c. The same Silurian formation largely pervades South Australia, running in a broad diagonal from the SE. coast, north-westward across the whole province. Though igneous rocks occupy a large area to the south and west of Western Australia, traces of Palæozoic formations are to be found in the Darling Range. No Carboniferous rocks are known in South and Western Australia. Detached patches of metamorphic rocks occur in Queensland, along the central line of the continent from Ashburton to the Macdonnell Ranges, and in the NW. of Arnhem Land. The older settlements of New South Wales, including the coal-field of the Hunter River, rest on sandstone. Fossiliferous Carboniferous strata, abounding in fine coal, extend over 50,000 sq. m. of Queensland, between 29° and 15° S. lat. The tin-mines of Queensland occur in granite, rising through the Carboniferous rocks. Sandstone and limestone, of Carboniferous or Permian formation, are found in the SE. of Victoria; and the two southern peninsulas of this province consist largely of limestone and carbonaceous deposits of Mesozoic age. The Secondary formations lie principally, however, in Queensland, where Cretaceous beds extend for about 200,000 sq. m., from near the Gulf of Carpentaria to the south of the Darling River. The valley of the Wannon (which runs into the Glenelg River) consists of Mesozoic strata, while the coal deposit of Parramatta to the north of Sydney is likewise of Mesozoic age. The Clarence River, to the north of New South Wales, runs through Triassic strata.
Tertiary deposits, mostly Pliocene, it is supposed, occupy an immense area of Australia, comprehending the desert sandstone, the coral limestone, and a large part of the conglomerates and clays of the gold-diggings. In Western Australia, to the east of the region of igneous rocks, the surface is occupied by desert sandstone, which also stretches north and eastward far into the interior, taking in likewise all South Australia outside the diagonal Silurian bed above mentioned, penetrating into the interior plains of Victoria and New South Wales, and skirting the eastern edge of the Cretaceous strata of Queensland. The earliest discoveries of gold in Australia were made in recent and Tertiary alluvia. The older auriferous drifts are believed to be of Tertiary age. These drifts are found filling up old valleys, and covering the low grounds that spread out from the base of the mountains. They appear to be all of fresh-water origin; vegetable remains (trees, fruits, &c.) occurring not infrequently in the various beds. During their accumulation volcanic action was rife, and sheets of lava were poured over the surface at successive intervals, so that in sinking shafts through these 'drifts,' the miner sometimes penetrates three or even four separate beds of lava. The gold is usually met with at the very base of the drifts, in the 'gutters' or 'leads,' which are just the bottoms of the old filled-up valleys. It may be added, that although gold is still obtained from such 'drifts,' yet the chief supply now comes from quartz-veins.
Quaternary deposits, forming 'flats' in the gold districts, occur in the Upper Macquarie and Upper Murrumbidgee rivers. These, with clay-deposits in the Liverpool Plains and Darling Downs of New South Wales, have yielded some very interesting fossils throwing light on the past fauna of Australia. A kangaroo, for example, has been found very much larger than any kangaroo of the present times (see DIPROTODON); also, a nototherium (an animal between the wombat and kangaroo) as large as a rhinoceros. Remains have also been discovered of a bird, named by Professor Owen dromæornis, larger than an ostrich, kindred to the now existing emu and cassowary.
Though there are no active, yet numerous extinct volcanoes are to be found in Australia. In South Australia, in the Gambier group, is a large series of them, which have broken through the horizontal coral beds, and whose craters now present beautiful lakes. In Victoria, a large part of the soil is volcanic, the débris of volcanoes of all periods down to the Tertiary. Looking from any high eminence in the neighbourhood of Ballarat, you may count extinct volcanoes by the score, some nearly closed up; but others having rims of some miles in circumference, from a few to a hundred feet deep, some rising to a height of 2000 feet.
Minerals.—Gold is distributed more or less through all the Australian colonies, but the principal mines were in Victoria, Queensland, and New South Wales, till those of Western Australia were developed (1891-95). Diamonds and other precious stones have been found in different parts of the continent. The Carboniferous strata of New South Wales, extending over a vast area, are very rich in coal, the coal-fields of that colony being among the most extensive in the world, containing also cannel-coal and mineral oils. The whole basin of the Hunter River, with its tributaries, down to Newcastle on the seacoast, abounds in true coal of Palæozoic age. Coal is found also at Cape Otway, and Western Port in Victoria, but belongs to the Mesozoic formation, and is not of great value. In the south of Queensland is an oolitic coal-field. Palæozoic coal, of great extent and great prospective value, has been discovered in the central regions of that colony, along the basins of the Mackenzie and Dawson rivers; while near Brisbane and the upper courses of the Darling Downs rivers, almost equally extensive and valuable beds of coal of Mesozoic age have been found. Rich copper-mines have been opened in the Palæozoic limestones of South Australia. The most important of the earlier mines was the Burra-Burra, 90 miles to the north of Adelaide, discovered 1845; after paying handsome dividends for many years, it has, however, been worked out. Still more extensive deposits of copper ore lie at Wallaroo and Moonta, at the northern end of York Peninsula. Many other copper-mines have been opened in South Australia, but consequent on the serious fall in the price of copper, operations have been suspended in most cases. Silver ore (principally argentite) is worked at Boorook, New South Wales, and mines of apparently inexhaustible wealth were discovered in 1884 at Silverton in the Barrier Ranges. Silver-lead has been worked near Cape Jervis (southern point of peninsula west of Alexandria Lake), and bismuth in the mountains of the Mount Lofty Range to the east of Adelaide. Lead and copper exist largely in Western Australia, particularly in the northern districts; it was not till about 1892-93 that the gold-fields of Western Australia (Coolgardie, Yilgarn, &c.) became famous. Iron exists in large masses in Western and South Australia, but in neither of these colonies has coal been found to work it. Very valuable tin-mines have been opened in Queensland, as also to the north of New South Wales. Ores of antimony have also been worked in Victoria and New South Wales, and are known to occur in South Australia.
Mining.—Gold-mining, which had declined for years, took a new start with the development of the field in Western Australia, whose export rose from £86,664 in 1890 to £787,099 in 1894. Till then the chief mines were in Victoria, where are seven mining districts: Ballarat, Sandhurst, Maryborough, Beechworth, Castlemaine, Ararat, and Gipps Land; the first three being the most productive. The principal gold districts of Queensland are the Peak Downs, Gympie, and Charters Towers. These gold-fields employ a large number of Chinese. The total yield of gold in Australia from 1851 to 1891 was about 100,000,000 ounces, valued at over £350,000,000. The annual yield for the several colonies averages still about £5,000,000. There are extensive coalfields in New South Wales