Page:Encyclopædia Britannica, Ninth Edition, v. 3.djvu/121

Rh related to the country north of the Kirchner range, watered by the Lynd, the Mitchell, the Walsh, and the Palmer Rivers, on the east side of the Gulf of Carpentaria. The coasting expedition of Mr G. Elphinstone Dalrymple, with Messrs Hill and Johnstone, finishing in December 1873, effected a valuable survey of the inlets and navigable rivers in the Cape York peninsula. The Endeavour River, in S. lat. 16, which was visited by Captain Cook a hundred years ago, seems capable of being used for communi cation with the country inland. A newly discovered river, the Johnstone or Gladys, is said to flow through a very rich land, producing the finest cedars, with groves of bananas, nutmeg, ginger, and other tropical plants. The colonial geologists predict that the north-east corner of Australia will be found to possess great mineral treasures. At the opposite extremity of the continent, its south-west corner, a tour lately made by Mr A. Forrest, Government surveyor, from the Swan River eastward, and thence down to the south coast, has shown the poorness of that region. The vast superiority of eastern Australia to all the rest is the most important practical lesson taught by the land-exploring labours of the last half century.

Physical Description. The continent of Australia, with a circumference -of nearly 8000 miles, presents a contour wonderfully devoid of inlets from the sea, except upon its northern shores, where the coast line is largely indented. The Gulf of Carpentaria, situated in the north, is enclosed on the east by the projection of Cape York, and on the west by Arnhem Land, and forms the principal bay on the whole coast, measuring about 6 of long, by 6 of lat. Further to the west, Van Diemen s Gulf, though much smaller, forms a better protected bay, having Melville Island between it and the ocean ; while beyond this Queen s Channel and Cambridge Gulf form inlets about S. lat. 14 50. On the north-west of the continent the coast line is much broken, the chief indentations being Admiralty Gulf, Collier Bay, and King Sound, on the shores of Tasman Land. Western Australia, again, is not favoured with many inlets Exmouth Gulf and Shark Bay being the only bays of any size. The same remark may be made of the rest of the sea-board ; for, with the exception of Spencer Gulf, the Gulf of St Vincent, and Port Phillip, on the south, and Moreton Bay, Hervey Bay, and Broad Sound, in the east, the coast line is singularly uniform. The conformation of the interior of Australia is very peculiar, and may perhaps be explained by the theory of the land having been, at a comparatively recent period, the bed of an ocean. The mountain ranges parallel to the east and west coasts would then have existed as the cliffs and uplands of many groups of islands, in widely scat tered archipelagoes resembling those of the Pacific. The singular positions and courses of some of the rivers lend force to this supposition. The Murray and its tributaries, the Murrumbidgee, the Lachlan, and the Darling, rising from the mountains on the east coast, flow inwards so far that they were at one time supposed to issue in a central sea. They do, in fact, spend their waters in a large shallow lake ; but this is not far from the south coast, and is provided with an outlet to the ocean. The Macquarie and the Lachlan merge in extensive swamps, and their beds in the dry season become a mere chain of ponds. This agrees with the idea that the whole country was a sea-bottom, which has scarcely yet assumed the character of permanent dry land, while another proof consists in the thinness and sterility of the soil in the lowlands. Along the entire line of the east coast there extends a succession of mountain ranges from Portland, in Victoria, to Cape York in the extreme north, called in different parts the Australian Grampians, the Australian Alps, the Blue Mountains, the Liverpool Range, and other names. These constitute, like the Andes of South America, a regular Cordillera, stretching from north to south 1700 miles in length, with an average height of 1500 feet above the sea. The rivers flowing down the eastern slope, having but short courses before they reach the sea, are of a more determined character than those which take a westerly and inland direction. They cut their way through the sand stone rocks in deep ravines ; but from their tortuous and violent course, and from the insufficient volume of water, they are unfit for navigation. Very few of them traverse more than 200 miles, inclusive of windings, or pass through any district extending more than 50 miles inland. It is different with the Murray, flowing westward, which has a course of 1100 miles, traversing a space from east to west measuring 8 of longitude. The Murray is navigable during eight months of the year along a great part of its course. This great river, with its tributaries, drains a basin the area of which is reckoned at half a million of square miles. Yet it has no proper outlet to the sea, de bouching into a lagoon called Lake Alexandrina, on the sea-coast of Encounter Bay. On the opposite or north western part of the continent there are several important water-courses. One river, the Victoria, which rises some where about 18 or 19 S. lat. and 131 E. long., flows northward to 15 D 30 S. lat., where it turns westward. Its bed forms a deep channel through the sandstone table land, with cliffs 300 feet high, while in width it sometimes extends to half a mile, its depth varying from 50 feet to as many fathoms. The Victoria debouches into Cam bridge Gulf, 14 14 S. lat. and 129 30 E. long., an estuary 20 miles broad, with a depth of 8 or 10 fathoms. To the westward of this district run two other large rivers, the Prince Regent and the Glenelg, the latter being navi gable, with a fertile country on its banks. The Roper, a navigable stream in Arnhem Land, has a width of 500 to 800 yards 40 or 50 miles from its mouth, which is at the Limmen Bight in the Gulf of Carpentaria. In the more settled and inhabited provinces of Australia there are the Brisbane, the Fitzroy, and the Burdekin, rivers of Queens land ; the Glenelg River, of Victoria ; and the Swan River, of West Australia. But this continent cannot boast of a Nile, an Indus, or a Mississippi, and the interior suffers from the want of water communication.

Geology. The interior plain of Australia, enclosed by the coast mountain ranges, is a vast concave table of sand stone, with a surface area of 1,500,000 square miles. The sedimentary rock, in some parts, has been washed away or scooped out ; but in the opinion of Mr W. H. L. Ranken (Dominion of Australia, 1874), the edges of the plateau, where highest and least reduced by denudation, are actually formed of this sediment. While the southern margin of the plain consists of walls of sandstone cliffs, extending along the sea-coast, the plateau on the east, south-east, the west, and partly on the north, is bordered by terraced ramparts of mountains. These elevations consist of granite and syenite on the west side, rising from 1000 to 3000 feet in height. On the east side, in New South Wales and Gipps Land, they rise to a much greater height, attaining 7000 feet at the south-east corner in the Australian Alps. Here, too, the sandstone masses are often violently rent asunder, and mingled with the overflows of igneous matter, forming basalt and trap. On the north side of the con tinent, except around the Gulf of Carpentaria, the edge of the sandstone table-land has a great elevation; it is cut by the Alligator River into gorges 3800 feet deep. In examining more particularly the geological structure of eastern Australia, we must take into account the neigh bouring island of Tasmania. The late Count Strzelecki, author of the first scientific essay upon the subject, in 1845; after minutely describing all the mountain ranges of 