I have already stated that the general outline and form of the Mount Lofty chain, bears a strong resemblance to the outline and form of the Ural mountains.  But it is of trifling elevation, running longitudinally from north to south, with a breadth of from 15 to 20 miles.  The metalliferous veins crop out on the surface of the ground, preserving the same longitudinal directions as the ranges themselves, and the rock in which the ores are imbedded, generally speaking, is a compact slate.  As the Mount Lofty ranges extend northwards, so does the Barrier or Stanley range, over which the recent expedition crossed on leaving the Darling; no copper ores were found amongst those hills, but an abundance of the finest ore of iron, running, as the out-croppings of the copper ores, from north to south, and occurring in depressed as well as elevated situations, the rock formation being very similar to that of the more western ranges.

If we are to judge from these facts, it is very evident that strong igneous action has influenced the whole, nor can I help thinking, from general appearances, that the continent of Australia has been subjected to a long subterranean process, by which it has been elevated to its present altitude, and it appears to me that that action, though considerably weakened, is still going on.  The occurrence of two slight shocks of earthquake felt at Adelaide, since the establishment of the colony, would further strengthen this opinion.

The copper ores of South Australia fetch a higher price at the Swansea sales than those from any other part of the world, not only because they are intrinsically rich, but because they are generally composed of carbonates, which are necessary to facilitate the smelting of the ores of sulphuret of copper from Cuba and other places.  The necessity for sending the ores from Adelaide to some foreign port to undergo the process of smelting, will probably exist for a considerable length of time; until such time, indeed, as the electric process shall be found to answer on a sufficiently large scale to be profitable, or, until smelting works are established; but, the great difficulty to be apprehended in carrying on such operations would be the want of fuel, which scarce even at the present moment, would soon be more so—­for there is not sufficient wood in the vicinity of any of the mines to keep up the supply for such a consumption as that which would be required; besides which, the cartage of the wood, and the expenses attending its preparation for the furnace, would materially diminish any profits arising from the smelting of the ores.  In such a view of the case I cannot but think that the establishment of works at the mines will be found to be as unprofitable to their proprietors as to the smelter, and that such works will only be remunerative when carried on under more favourable circumstances—­for it would appear that coal is the only mineral South Australia does not possess, and I am apprehensive that no bed of it will ever be found in the colony.  I have ever thought the geological formation of the country unfavourable to the presence of coal, but, still, it is said to exist as a submarine formation close to Aldingi Bay.  The discovery of this mineral in the province would immediately give to it, within itself, the means of the most unbounded wealth, and would undoubtedly fill up the measure of its prosperity to the brim.