Geology.—Geologically Sardinia consists of two hilly regions of pre-Tertiary rock, separated by a broad depression filled with Tertiary deposits. This depression runs nearly from north to south, from the Gulf of Asinara to the Gulf of Cagliari. Physically its continuity is broken by Monte Urticu and smaller hills, re mains of Tertiary volcanoes. In the south the depression is known as the Campidano. In the north it forms the plain of Sassari. Both east and west of this depression the Archaean and Palaeozoic rocks are strongly folded, except the Permian beds. In the eastern region this was the last folding which has affected the country, and the Mesozoic and Tertiary beds are almost undisturbed. In the western region, on the other hand, all the Mesozoic beds are involved in a later system of folds ; but here also the Tertiary beds lie nearly horizontal. In the western region all the Mesozoic systems, including the Trias, are well developed. The Trias does not belong, as might have been ex pected, to the Alpine or Mediterranean type; but resembles that of Germany and northern Europe. In the eastern region the Trias is absent ; the Mesozoic series begins with the Upper Jurassic.
Granite and Archaean schists form nearly the whole of the eastern hills from the Strait of Bonifacio southwards to the Flumendosa river, culminating in the Monti del Gennargentu. The Palaeozoic rocks form two extensive masses, one in the south-east, the other in the south-west. They occur also on the extreme north-western coast, in the Nurra. Cambrian, Ordovician and Silurian beds have been recognized, the Upper Cambrian con sisting of a limestone which is very rich in metalliferous ores (especially galena and calamine). The Permian, which contains workable coal seams, lies unconformably upon the older beds and seems to have been deposited in isolated basins (e.g., at Fondu Corrongiu and San Sebastiano), like those of the Central Pla teau of France. The Mesozoic beds are limited in extent, the most extensive areas lying around the Gulf of Orosei on the east and west of Sassari in the north. The Tertiary deposits cover the central depression.
Climate.—The climate of Sardinia is more extreme than that of Italy, but varies considerably in different districts. The mean annual temperature is 62° F at Cagliari and 61° F at Sassari, the respective maxima and minima (for a period of 3o years) being 98.5° F and F and 36.5° F and 38.5° F. The island is subject to strong winds, which are especially felt at Cagliari owing to its position at the south-east end of the Campidano, and the autumn rains are sometimes of almost tropical violence. There are com paratively few streams and no inland lakes. Snow hardly ever falls near the coast, but is abundant in the higher parts of the island, though none remains throughout the summer. The rain fall in the south-west portion of the island is considerably greater than in other districts, in which it is extremely low, about 19 in. at Cagliari and 24 in. at Sassari.
while among the modern population 6o% of males and females together fall below 1,250 c.c. and the stature is generally lower than in other parts of Italy. In the province of Cagliari 29.99% of the recruits born in 1862 were under 5 ft. 1 in., and in that of Sassari 2 1.99% , the percentage for ten provinces of south Italy being 24.35. These small individuals present apparently no other differences, and Sergi maintains that the difference is racial, these being descendants of a race of pygmies who had emigrated from central Africa. But the lowness of stature extends to the lower animals—cattle, horses, donkeys, etc.—and this may indi cate that climatic causes have some part in the matter also.
The dialects differ very much in different parts of the island, so that those who speak one often cannot understand those who speak another, and use Italian as the medium of communication. They contain a considerable number of Latin words, which have remained unchanged. The two main dialects are that of the Logudoro in the north and that of Cagliari in the south.
The native costumes also vary considerably. In the south-east they have largely gone out of use, but elsewhere, especially in the mountainous districts, they are still habitually worn. In the Barbargia the men have a white shirt, a black or red waistcoat and black or red coat, often with open sleeves ; the cut and decorations of these vary considerably in the different districts. They have a kind of short kilt, stiff, made of black wool, with a band from back to front between the legs; under this they wear short linen trousers, which come a little below the knee, and black woollen leggings with boots. They wear a black cap, about ft. long, the end of which falls down over one side of the head. In other districts the costume varies considerably, but the long cap is almost universal. Thus at Ozieri the men wear ordinary jackets and trousers with a velvet waistcoat ; the shepherds of the Sulcis wear short black trousers without kilt and heavy black sheepskin coats, and the two rows of waistcoat buttons are generally silver or copper coins. The costume of the women is different (often entirely so) in each village or district. Bright colours (especially red) are frequent, and the white chemise is an integral part of the dress. The skirts are usually of the native wool (called orbacia) and two are often Worn, one over the other. For widows or deep mourning the peculiar cut of the local cos tume is preserved, but carried out entirely in black. The native costume is passing out of use in many places (especially among the women, whose costume is more elaborate than that of the men), partly owing to the spread of modern ideas, partly owing to its cost ; and in the Campidano and in the mining districts, it is now rarely seen. The curious customs, too, of which older writers tell us, are gradually dying out. But the festivals, es pecially those of mountain villages or of pilgrimage churches, attract in the summer a great concourse of people, all in their local costumes. There may be seen the native dances and bare back horse-races through the main street of the village.