On the western side of the island are the small _Campi_ of Anglona, lying round Castel Sardo, and another plain highly cultivated between Sassari and Porto Torres. The largest of these plains on the eastern side of the island is that of Orosei, washed by several rivers having their sources in the neighbouring primitive chain of mountains. Westward of this chain we have the great central plain, which, first surrounding the Gulf of Oristano, extends in an unbroken line, for upwards of fifty miles, to the Gulf of Cagliari. This is generally spoken of as “_the Campidano_,” without further specification, though its parts are distinguished by local names, such as—di Uras, di Gavino, &c.
The mineral riches of Sardinia were well known to the ancients, and vast excavations, with the remains of a number of foundries, afford ample testimony of the extent of their operations. Tradition asserts that gold was formerly extracted; and there is no doubt that silver was found in considerable quantities, as it is even now procured in assaying the lead. Copper is found near Cape Teulada, and at other places, and in one of the mines beautiful specimens of malachite occur. Iron is very plentifully distributed, but is found principally at the Monte Santo of Cape Teulada, and at Monte Ferru. The richest mine is in the Ogliastra, where the _intempérie_, however, is so malignant as to preclude the formation of an establishment. Lead is the most abundant of Sardinian ores, and its mines are profusely scattered throughout the islands.
Anthracite has been found, but only that of the Nurra district is fit for working; and the coal, though met with in various places in the secondary formations, and especially in the lower parts of the beds of magnesian limestone, is neither sufficient in quantity nor good enough in quality to be generally used. The granites of the Gallura, as we have already mentioned, were known to the ancients, and highly appreciated in Italy for their beauty and colours. Among the other mineral products may also be mentioned the porphyries of the Limbara, the basalt of Nurri, Gestori, and Serri, the alabaster of Sarcidanu, and the marbles of the Goceano and Monte Raso. Jasper abounds in the trachyte and dolomite, and large blocks, of beautiful variety, are found in some districts. Among the chalcedonies are the sardonyx, agates, and cornelian. The districts from whence the ancients obtained the sardonyx, once held in high repute, are not known, but the vicinity of Bosa abounds in chalcedenous formations. A fine quality of quartz amethyst has been obtained, and also hydrophane, known for its peculiar property of becoming transparent when immersed in water. Good turquoises and garnets are also found, but not frequently. Though there have been so many volcanoes, and selenite, gypsum, lime, and aluminous schist frequently occur, neither sulphur nor rock salt have been discovered, and but very little alum. Mineral springs are numerous, but not much frequented.