About 100 m. from the bounding tract of pakeozoic rocks on the eastern limits of A.., and running parallel with it, there is an equally broad strip of similar strata extending from the shores of the gulf of Carpentaria to Bass's strait. These two regions, which unite together and are largely developed in the southern Portion of Victoria, supply the great store of Australian Mineral wealth. The veins which intersect these strata were the original matrices of the gold. It has not, to any extent, been sought for in this, its original position, from a belief that the amount of metal decreases as we descend in the solid rock. Mr. Selwyn, colonial geologist for Victoria, has, however, lately reported in favor of quarrying for the gold in the solid rock. The greatest amount of gold is found in the heaps of debris or old alluvium derived from the denudation of the old slaty rocks. The auriferous rocks of eastern A. are lower silurian, as shown by Messrs. Lonsdale and Salter, from the examination of specimens of pentameri, trilobites, and corals from the strata which overlie them. Mr. Selwyn has referred the Victoria gold bearing strata to the same age, from the occurrence in them of about CO species of lower silurian fossils, including trilobites, graptolites, and lingulie. The auriferous quartzose veins are most abundant in the vicinity of eruptive rocks, whether granite, porphyry, or greenstone.
Messrs. Selwyn and Rosales have shown that the superficial drifts containing the gold consist of three distinct stages. The lowest or oldest contains the remains of wood and seed-vessels differing little from the present vegetation; among them the cones of banksia, an exclusively Australian genus, have been identified. The remains of animals exhibit also the representatives of the living fauna of the country. Gigantic marsupials then existed—kangaroos, potoroos, and wombats—representing the elephants, and even the large carnivore of Asia; but with the exception of the mastodon, of which one species has been found in A., there were, it would seem, no generic forms common to this great district and the rest of the land in the eastern hemisphere. In Victoria, these beds of alluvium have been overflowed and even interlaced by basaltic coulees, which evidently proceeded from terrestrial volcanoes, inasmuch as the vegetable matter beneath them has been charred and destroyed in situ by the eruption.
An extensive has been known for some time as occupying the whole of the great basin of the Hunter river and its tributaries, down to the sea-coast at Newcastle, where several beds crop out on the beach. For a good many years, the monopoly held by the Australian Agricultural Company, in the working of the coal, has ceased to exist, and as the result, the trade has increased enormously. From Port Hunter the coal is dispatched to all parts of A., and even to New Zealand and California. Beds belonging to the carboniferous system have been discovered also in western A., near Perth, and the coal has been successfully, though not so extensively wrought there.
After gold and coal, the next most important Australian mineral is copper. The Burra Burra mines, in South A., were discovered in 1842. The lode is 17 ft. wide, and of vast extent. The ore contains 75 per cent of metal, and is quarried out like stone in immense masses. Copper has also been wrought for several years at Bathurst, in
New South Wales. The poorest ores are here most abundant, the rich pyrites existing only in small quantity. Copper is now mined and smelted in western Australia.
Iron is spread in great profusion over all the continent. To such an extent does it exist in several of the mountains on the north coast, that they violently affect the magnetic needle. At Berrima, in New South Wales, an oxidulated iron ore, from which is manufactured a good steel, has been worked, but not successfully. Iron has been noticed in quantity in both southern and western Australia.
Lead is most abundant e. and s.e. from Adelaide, at Mt. Beevor, and near cape Jervis. The ore of Glen Osmond mines, near Adelaide, yields 75 per cent of lead, besides a proportion of silver. This metal is also wrought at Geraldine, in western Australia.
Manganese, bismuth, tin, and antimony have been met with in South A., as also good specimens of jasper, chalcedony, and opal.
Zinc and quicksilver are mentioned as occurring in western Australia.
Botany and 'Zoning natural history of A. is remarkably different from that of any other quarter of the globe. Its 'trees—which seldom form deose forests, but are scattered as in a lawn or park, where the colonist finds pasture for his flocks without any previous clearing—are, almost without exception, of very peculiar appearance. Among the largest of them are species of eucalyptus (q. v.), some of which attain the height of 150 or 200 ft., rising without branches to at least half their height, their stately stems resembling beautiful columns. Some of the eucalypti, on account of their resinous exudations, are known to the colonists as gum-trees. Their leaves are leathery. It is. indeed, a general characteristic of the trees and shrubs of A., that their leaves are ever green and of a firm texture; and although in this a beautiful adaptation may be perceived to the prevailing dryness of the climate, the foliage wants the delicacy anti the liveliness of tints which in other countries form so much the charm of the landscape. The (see CASUARINA) or cassowary-trees (beef-wood, she-oak, swamp-oak, etc.), among which, as among the eucalypti, are some of the largest and most useful timber-trees, are still more singular in appearance; their long, wiry, jointed branclilets, which greatly resemble those of equiseta, are quite leafless, having only very small sheaths instead of leaves. Equally destitute of foliage are the greater number of the acacias (q.v.), which abound in the Australian flora. The abundance of proteaccer which order includes the genus /winks/a.. already noticed in the geology—connects the flora of A. with that of the cape of Good Hope, to which there are also other points of resemblance; and although true heaths do not appear. their place is supplied by a variety of heath-like plants of other natural orders, and particularly. .of the order opacrMacea, of wnich some (of the genus epacri8) now take their with heaths among the favorite oraaments of our greenhouses. Araucariax (q.v.) form a connecting link between the tiont of A. and that of Chili. In the more northern parts, palms and other tropical productions connect it in like manner with that of the s.e. of Asia.