Such being the hydrography of A., the investigation of the interior, so far as it has hitherto advanced, has been conducted almost entirely by land. In 1844, Sturt pene trated to the center of the country, between Spencer gulf on the s.. and the gulf of Car pentaria on the n., meeting sterility and drought. In 1847, Leichhardt, encouraged by the success of his previous expedition from Sydney to Port Essington, started from Moreton bay on the e., for western A., following iLsort of diagonal of nearly the greatest possible length; and, as was to be dreaded, he must have failed in his bold enterprise; for neither of himself nor of his companions has any intelligence ever been received. Subsequent explorations made by Stuart (1858-62), Burke and Wills (1800-61), and by expeditions in search of them, have resulted in the discovery that this interior of • the Australian continent is, on the whole, well fitted for pastoral, and, in many places, for agricultural purposes. See AUSTRALIAN EXPLORATIONS. Any detailed view of the climate, besides being equally difficult and unsatisfactory with respect to so vast an aggregate of latitudes and longitudes, has been rendered comparatively unnecessary by the incidental allusions to the subject in the preceding paragraphs. The following arc tabular statements extracted from local publications: The mean temperature of Melbourne is 59°, being about 9' higher than that of Lon don. The warmest month is Jan., the mean of Which is 68"; the coldest is July, 49'.34. The corresponding temperatures of London are 63° and 36°.
little that is yet known of the geology of A. has been chiefly obtained from occasional notes scattered through the journals of scientific travelers. So utterly unknown were the mineral treasures of this continent, that it was only compara tively lately, and by the merest accident, that the Burnt Burra copper-mines were discovered. In 1831, farmers were turning up with the plow the auriferous alluvium; pebbles of gold-bearing quartz were used for garden-walks; and we have heard of an Oxford graduate who ornamented his garden-walls by building into them masses of white quartz variegated with portions of the unrecognized yellow metal. In 1846, when count Strelecki submitted to Sir R. Murchison a series of rock and mineral specimens gathered in southern A., the practiced eye of that veteran in geology recognized in them a remarkable resemblance to the rocks in the auriferous districts of the Ural mountains, which lie had thoroughly explored. He could not ascertain that gold had ever been found in the colony, but so certain was he that the precious metal existed, that he printed and circulated amongst the miners of Cornwall a paper urging them to emigrate to New South Wales, and seek there for gold, as they had been accustomed to seek for tin and zinc among the alluvial debris of their own bills. After a few years, in the researches of Mr. Hargreaves, and the diggings that followed, this remarkable predic
tion was fulfilled to an extent that could not have been anticipated. This narrative is of much value, as showing that geology is no longer in the hands of empirics; that its truths have been so gathered and arranged as to afford bases for safe inductions; and that, when rightly used, this science is of the first importance, even when tested by the utilitarian eui bono ? of the age. Recognizing this, the colonial governments of A. have appointed state geologists, who have begun their examination of the Australian continent, and hive published several reports.
In looking at the continent as a whole, it will require not many broad touches to convey all that is at present known. An immense, roughly quadrangular and compara tively fiat district in central A., extending from the southern shores in lat 33° s., where it forms a coast-line of somewhat bold cliffs, to 18° s. lat., and having for its eastern and western limits 124' and 138' e. long., is composed of tertiary rocks. The super ficial characteristics of this vast almost unpeopled tract have already been described. Nothing more is known regarding its structure. Three other patches of tertiary rocks exist. The largest is a broadish tract, which forms the coast of western A. northwards from the colony of Perth, as far as the tropic of .Capricorn. The second occupies a considerable of the valley of the Murray river, in tl.at district khown as lower Darling. The last and smallest patch covers the southern slope of the Australian Alps, extending along the shore from Wilson's promontory to cape Howe.
The immense central expanse of tertiary beds is surrounded by a continuous belt of plutonic and metamorphic rocks, only broken on the southern shores, where it forms the coast-line, and where the sea has indented it, forming a bay which has for its bound aries the more enduring primitive rocks. This crystalline belt is, on its e., n. and western sides, separated the sea by a tract of land having a nearly equal breadth of 100 in. throughout its course. Tracing this from its southern termination in western A., we find a limited region of palwozoic rocks occupying the colonized district around Perth. and containing valuable coal-beds. Northwards, as already indicated, the coast line consists of tertiary rocks. From their termination in lat. 231° s., the rocks along the whole western and northern shores are composed of secondary strata. On the eastern shore. from cape York to the western boundary of Victoria, the formations belong, to one or other of the primary series. Through the whole extent of this boundary tract., whether consisting of tertiary, secondary, or primary strata, numerous and often extensive patches of igneous rocks exist which have been erupted during the tertiary or post-tertiary epochs.