AP'ENNINES (Ital. Appenntni; anciently, Lat. Mons Apennnius), a mountain-chain extending uninterruptedly throughout the whole length of the Italian peninsula. It lies between 37° and 44° 30' n. lat., and 7°40' and 18° 20' e. long., and belongs to the system of the Alps, from which it branches off at the Col de Tenth', near the sources of the Tanaro. From this point, the chain, under the name of the Ligurian A., girdles the gulf of Genoa, in the immediate vicinity of the sea, and then runs inland to a considerable extent, forming the water-shed between the Adriatic and the Mediterranean, but gradually approaching the east coast, till, in the highlands of the Abruzzi, it is close upon it; after which it takes a south-western direction through Naples, dips under the sea at the strait of Messina, and reappears on the northern coast of Sicily. Recent geographers divide the A. as follows: 1. The Korth A., from the Co] de Tcnda in the Maritime Alps to the pass of Borgo San SepoIcro, in the neighborhood of Arezzo, on the eastern border of Tuscany. 2. The Central A., from Arezzo to the valley of Pescara, which flows between the two Abruzzi. 3. The South A., from the valley of the Pescara to cape Spartivento. 4. The insular A., or the Sicilian range. The leading feature of the A., wherever they approach the coast, is their extraordinarily steep acclivities: which in middle Italy and the adjoining portions of upper and lower Italy, long terraced plateaus, lower ranges, and, finally, extensive coast-plains, mark their gradual descent on the west. The general name for these lower ranges is Sub-Apennine; but they have a variety of particular designations, such as, the mountains of Carrara and Seravezza, Protomagno and Monte Amiata, in Tuscany; the Sabine, Alban, and Volscian mountains, in the former papal states; Monte Gargano on the s.e. coast, n. of Manfredonia, etc. The main chain of the A. does not send off spurs into the Apulian peninsula, or heel of Italy, which, for the most part, is rather level, or only interspersed with detached groups (1 hills. • The direction of the great chain of the A. is favorable to the formation, on the w. side, of important river-basins, such as those of the Arno, the Tiber, the Garigliano, and the Volturno; while, on the 0. side, we find nothing but small streams, in most cases, destitute of affluents, hurrying down to the sea through wild precipitous valleys. In northern Italy, the Ligurian A., almost overhanging the gulf of Genoa, can only develop on the s. puny streams, while the a. sends down, through the plains of Piedmont, large tributaries to the Po.
The average height of the entire chain of the A. is about 4000 ft., which, however, in the n., sinks down to little more than 3300 ft.; and in the mountains of the Abruzzi, rises to 7000 feet. Here, in Monte Corno, the highest peak of the range known under the name of Gran Sasso d'Italia, they reach an elevation of 10,200 ft., and in Monte Velino of 7850 feet. The North A. attain, in Monte Cimone, situated in the s. of Modena, a height of 6973 ft.; the South A., in Monte Amara, a height of 0000 ft.; the Insular A., if we exclude the isolated peak of .iEtna. in Pizzo di Case, a height of 6500 feet.
The A. are crossed by 13 principal passes: these are, proceeding from n. to s.-1. The pass of Savona; 2, of Bocehetta; 3, of Cisa; 4, of Monte Cimone: 5, of Porretta; 6, of Pietramala; 7, of Borgo San Sepolcro; 8, of Furlo; 9, of Serravalle; 10, of Aquila; 11, of Isernia; 12, of Arcano and Troja; 13, of Potenza. The prevalent stone is a species of compact limestone, of a whitish-gray color, belonging to the Jura formation. Resting on the limestone is found a more recent formation of sandstone and marl, which is especially abundant in the middle region of the Sub-A., contains an extraordinary num ber of petrifactions, and must be reckoned as belonging to the upper division of the Parisian limestone. Older formations, however, frequently crop out. Thus, for instance, on the water-shed of the North and Central A. there are found transition clay-slate, grauwacke-slate, etc. The A., especially the Roman and Neapolitan, are distinguished from all other mountain-chains by the rich variety of marbles which they contain. In some places the quarries seem inexhaustible. Volcanic rocks are numerous in the middle and southern regions, where the agency of fire has caused very wonderful formations, as, for instance, the crater-lakes of Albano, Nemi, Vesuvius, Solfatara.
The principal chain exhibits, for the most part, a dreary and barren appearance; it looks like a vast wall, with very few projecting peaks to break the dull monotony of the scene, and therefore seldom furnishes any salient points on which the eye of the spec tator can rest with pleasure. Naked, riven, covered with thick debris, the declivities seem as if scorched by the southern sun. Only in the Abruzzi, in the sub-A., and above all, in the marble mountains of Carrara and Seravezza, do the bold and magnifi cent forms of the Alps reappear. Where the A.—in general so poorly supplied with streams—exhibit a trace of Alpine abundance of water, there is no lack of rich pastures and dense forests, but usually only thin grass and wild scrubby bushes cover the stony slopes. The greater number of the roaring forest brooks, in the deep rocky ravines, dis play, during summer, only a dry bed. Where the mountains dip down to the sea, as at the riviera of Genoa, and the gulf of Naples, a rich, peculiarly southern vegetation clothes the declivities. Gigantic agaves, Indian figs (cactus opunt.a), myrtle-bushes, orange-groves, hint in these northern lands of the splendors of the tropics. Up to 3000 ft. of elevation, cornfields, fruit bearing chestnuts, and deciduous oaks are found. Beyond this, all vegetation often ceases on the steep and stony sides of the mountains; but at other times the beech or the fir appears in dense forests. There is no region of perpetual snow; but the summits of the Abruzzi and the lofty peaks of Lunigiana, are often covered with snow from Oct. far into May. and send their icy breath so suddenly down into the mild valleys, that the temperature in a few hours sinks 12° to 18' F., and a warm spring afternoon is succeeded by a bitter Dec. evening.