The greater part of the Murray-Darling basin is filled up by recent rock sediment and river alluvium; but the narrow belt of country with a moderate rainfall, lying between the plateau edge and the western plains, has not depended for its development solely on agriculture. All along it the older rocks crop out, and in the older rocks we find the valuable minerals in which Australia abounds. Gold, in its alluvial form, occurs all along the agricultural belt; and since the time of the first discovery near Bathurst, in 1851, the search for gold has often caused an inrush of people who have abandoned mining for the more secure and pleasant business of growing wheat or rearing sheep. Though much gold is still produced, New South Wales is not by any means the chief of the States to-day in this respect; but gold has been woven deeply into her history. One of the most usual methods of obtaining gold is still by dredging alluvium; but in place of the shovel and washing-pan we have the ugly machine dredger scooping out the creeks and flats where the gold is to be found. We must look elsewhere for gold-mining from the rock on a large scale; though this is increasing in New South Wales in connexion with the development of mining for other minerals, especially copper. Well out in the plains, and south of Bourke, at the end of a branch line of railway, is the town of Cobar; it stands just where the old rocks are disappearing underneath the recent deposits. Here is one of the chief centres of copper mining; and, once the work was started, mining for other ores naturally followed. It is a desolate country, rendered more so by the nature of the industry. The furnaces for the rough smelting of the ores need fuel, but coal is far away; so that the country round has been stripped of its small supply of timber, and has nothing left to relieve its ugly monotony. The ore, partly worked, is sent by rail all the way to Lithgow, on the coalfield, to undergo the further process of refining. The importance of these mining fields to the State lies not so much in the money value of the products as in the fact that they give rise to railways and traffic and so to a further spread of the settled agricultural population. The minerals, and especially gold, have played a great part in the settlement of the less accessible or less attractive regions of Australia.