Another point agreed upon is that the Australian flora is one of vast antiquity.
Cambrian rocks occur in each of these districts, and they are best developed in the South Australian high= lands, where they include a long belt of contemporary glacial deposits.
Of those peculiar to Australian waters may be mentioned the arripis, represented by what is called among the colonists a salmon trout.
In 1908 a movement began for the establishment of Australia.
A narrow Cambrian sea must have extended across central Australia from the Kimberley Goldfield in the north-west, through Tempe Downs and the Macdonnell chain in central Australia, to the South Australian highlands, central Victoria at Mansfield, and northern Tasmania.
1 - The Australian people are mainly of British origin, only 34% of the population of European descent being of non-British race.
A further gentle rise in the high steppes leads to the mountains of the West Australian coast, and another strip of low-lying coastal land to the sea.
From a geological standpoint, the Great Australian Plain and the fertile valley of the Nile have had a similar origin.
The numerous facts, geological, geographical and biological, which when linked together lend great support to this theory, have been well worked out in Australia by Mr Charles Hedley of the Australian Museum, Sydney.
Except the opossums, no single living marsupial is known outside the Australian zoological region.
The Australian eucalyptus is now grown in many places, and there are groves of the paradise or paraiso tree (Melia azedarach) on the formerly treeless pampa.
12), a west Australian creature of the size of a mouse, which may be regarded as representing by itself a sub-family (Tarsipediinae), characterized by the rudimentary teeth, the long and extensile tongue, and absence of a caecum.
Round the Australian Bight it continues parallel to the coast, until south of Spencer Gulf (the basal ledge still averaging 8000 ft.
The terrace closest to the land, known as the continental shelf, has an average depth of 600 ft., and connects Australia, New Guinea, and Tasmania in one unbroken sweep. Compared with other continents, the Australian continental shelf is extremely narrow, and there are points on the eastern coast where the land plunges down to oceanic depths with an abruptness rarely paralleled.
The higher Australian peaks in the south-east look just what they are, the worn and denuded stumps of mountains, standing for untold ages above the sea.
The coastal belt of Australia is everywhere well watered, with the exception of the country around the Great Australian Bight and Spencer Gulf.
Westward of South Australia, on the shores of the Australian Bight, there is a stretch of country 300 m.
Taking the Lachlan as one type of Australian river, we find it takes its rise amongst the precipitous and almost unexplored valleys of the Great Dividing Range.
All Australian rivers, except the Murray and the Murrumbidgee, depend entirely and directly on the rainfall.
This period was marked by intense earth movements, which affected the whole of the east Australian highlands.
Similar granitic intrusions occurred in New South Wales and Queensland, and built up a mountain chain, which ran north and south across the continent; its worn-down stumps now form the east Australian highlands.
The sea does not appear to have extended completely across Australia, breaking it into halves, for a projection from the Archean plateau of Western Australia extended as far east as the South Australian highlands, and thence probably continued eastward, till it joined the Victorian highlands.
The Kainozoic period opened with fresh earth movements, the most striking evidence of which are the volcanic outbreaks all round the Australian coasts.
The sea encroached far on the land from the Great Australian Bight and there formed the limestones of the Nullarbor Plains.
The great monoclinal fold which formed the eastern face of the east Australian highlands, west of Sydney, is of later age.
Tasmania and Victoria were separated by the foundering of Bass Strait, and at the same time the formation of the rift valley of Spencer Gulf, and Lake Torrens, isolated the South Australian highlands from the Eyre Peninsula and the Westralian plateau.
M., is so immense, that the moist air from the ocean does not come in sufficient supply, nor are there mountain chains to intercept the clouds which from time to time are formed; so that two-fifths of Australia, comprising a region stretching from the Australian Bight to 20° S.
These immigrants then developed, with some exceptions, into the present Australian flora and fauna.
On the Australian side the fact that Tasmania is richest in marsupial types indicates the gate by which they entered.
Putting aside the exotic vegetation of the north and east coast-line, the Australian bush gains its peculiar character from the prevalence of the so-called gum-trees (Eucalyptus) and the acacias, of which last there are 300 species, but the eucalypts above all are everywhere.
As early as 1866, tannic acid, gallic acid, wood spirit, acetic acid, essential oil and eucalyptol were produced from various species of eucalyptus, and researches made by Australian chemists, notably by Messrs.
But the Transvaal War of 1899-1902, to which Australia sent 6310 volunteers (principally mounted rifles), and the gradual increase of military sentiment, brought the question more to the front, and more and more attention was given to making Australian defence a matter of local concern.
The marsupials constitute two-thirds of all the Australian species of mammals.
Behind the luxuriant jungles of the sub-tropical coast, once over the main range, we find the purely Australian flora with its apparent sameness and sombre dulness.
They serve admirably to break the sombre and monotonous aspect of the Australian vegetation.
Grasses and herbage in great variety constitute the most valuable element of Australian flora from the commercial point of view.
Proteaceous plants, although not exclusively Australian, are exceedingly characteristic of Australian scenery, and are counted amongst the oldest flowering plants of the world.
They are found in New Zealand and also in New Caledonia, their greatest developments being on the south-west of the Australian continent.
The " grass-tree " (Xanthorrhoea), of the uplands and coast regions, is peculiarly Australian in its aspect.
This terminates in a long spike thickly studded with white blossoms. The grass-tree gives as distinct a character to an Australian picture as the agave and cactus do to the Mexican landscape.
No speculation of hypothesis has been propounded to account satisfactorily for the origin of the Australian flora.
As a step towards such hypothesis it has been noted that the Antarctic, the South African, and the Australian floras have many types in common.