Page:Encyclopædia Britannica, Ninth Edition, v. 21.djvu/328

Rh SARDINIA ages form the ridge or saddle, about 2000 feet high, cou- nectiDg this mountain with the highland area on the east. Still further north a trachytic plateau, intersected by numerous deep river valleys, occupies a considerable tract, advancing up to the plain of Sassari on the north coast. M E D I'T E R RA'N EAN Map of Sardinia. The rivers are numerous but short. The principal is the Oristano, which enters the gulf of the same name on the west coast. Geologically the island is composed mainly of granite and other crystalline rocks. Granite predominates espe- cially in the east, and the mountains of that part of the island were apparently at one time continuous with the similarly constituted mountains of Corsica. Granitic spurs likewise extend to the south-west, and appear in the capes of Spartivento and Teulada. Altogether this rock is estimated to cover one-half of the entire surface. In the west of the island the principal crystalline rocks are porphyritic in structure ; sedimentary deposits are com- paratively unimportant, and such as are present are mainly cither of very ancient or of recent geological date. Silurian formations attain their most considerable development in the south-west round Iglesias, where there occurred the contemporaneous porphyritic outpourings containing the most numerous mineral veins of the island. Between the deposits of Silurian and those of Cretaceous times there an none of any consequence except a few patches of Devonian round the slopes of Gennargentu, interesting as containing some beds of true coal. The members of the Cretaceous system occupy considerable tracts in the south- west, east (round the Gulf of Orosei), and north-west (in the mountains of Nurra), and a smaller area in the south- west (in the island of San Antioco). Tertiary formations are still more largely developed. They cover the whole plain of the Campidano, the west coast opposite the island of San Antioco, and the narrow valley in the north rast already mentioned. The basalts of Monte Ferru are also of Tertiary date, and it does not appear to have been till that epoch that Sardinia formed a single island. In variety of mineral wealth the southern half of Sardinia is the richest province of Italy, and it stands second in the annual value of its mineral products. The chief minerals are sulphates of lead more or less argenti- ferous (galena), sulphates and silicates of zinc, ordinary iron pyrites, sulphates of iron and copper, of antimony, and of arsenic, besides cobalt, nickel, and silver. The coal on the flanks of Gennargentu is of good enough quality to furnish a valuable fuel, and is found in sufficiently thick seams to be workable if only the means of transport were present, but its situation is such as to render it of no economical importance. In the Tertiary deposits of the south-west there are some veins of manganese ore, and also some beds of lignite which are worked as a source of fuel for local use. The mineral wealth of Sardinia was known in ancient times, and mines were worked both by the Carthaginians and the Romans. During the Middle Ages they were for the most part neglected, but the industry was revived in modern times, and has been greatly developed in recent years. Upwards of 70 mines have now been opened, most of them in the district of which Iglesias is the centre, but a few near the southern part of the east coast, where Muravera is the chief town. The mines are mostly of argentiferous lead, silver, zinc, and iron. The ores are mainly exported in the raw state, only the inferior sorts being smelted in the island. Among other mineral products are building stones (granite, marble, <fec.), alabaster, and salt. The climate of Sardinia is similar to that of the rest of the Mediterranean region, and the southern half of the island shares in the nearly rainless summers characteristic of the southern portions of the Mediterranean peninsulas. At Cagliari there are on an average only seven days on which rain falls during June, July, and August. Through- out the island these months are the driest in the year, and hence vegetation on the lower ground at least is generally at a standstill during that period, and shrubs with broad leathery leaves fitted to withstand the drought (the so- called maquis) are as characteristic here as in Corsica and on the mainland. Winter is the rainiest season of the year ; but the heat and drought of summer (mean tempera- ture 95 F.) make that the most unpleasant of the seasons, while in the low grounds the prevalence of malaria renders it a most unhealthy one, especially for visitors. Autumn, which is prolonged into December, is the most agreeable season ; there is then neither heat nor cold, nor mist nor fever, and at that period birds of passage begin to immi- grate in large numbers. The agricultural products of the island are greatly inferior to what might be expected in view of the natural fertility of the soil. Two causes are assigned for this. The first is the minute subdivision of the land, which, as in Corsica, is carried to such an extent that where an owner has as much as 100 acres his property is divided into 25 or 30 lots surrounded by parcels of land belonging to other owners. In such circumstances it is neither possible to apply adequate capital to the cultivation of the ground, nor for the owners to acquire the requisite capital. The second cause is the malaria which renders certain districts possessed of a fertile soil quite uninhabitable ; and this second cause can be remedied only when a remedy has been found for the first, for, as the malaria is undoubtedly one cause of diminished cultivation, ifis equally certain that want of cultivation is one of the causes of the malaria. In ancient times Sardinia was one of the granaries of Rome ; now cereals take a comparatively unimportant place among the exports, and this export is balanced by a considerable import of the same commodity. The chief products of agriculture are wheat, barley, and beans, the last furnishing an important element of the food of the people. Olives run wild in many places, and are grown in sufficient abundance to meet the local demand.