The surface of the whole peninsula, including both the leg of Italy and the irregular figure at the top, is estimated at about ninety thousand square miles, or an area nearly equal to the surface of Great Britain and Ireland. But a very large proportion of this surface is unproductive, and a great part even incapable of tillage.
The geographical features are simple. No deep gulfs and inlets are to be expected; for these are only found when mountain chains jut out into the sea, and maintain themselves as headlands, while the lower land between is eaten and washed away by the ceaseless action of the waves. Such phenomena are presented by Greece, and by the western coasts of Scotland, Wales, and Ireland. But in Italy there is but one uniform mountain chain. On the northern or Adriatic slope of the Apennines, indeed, a number of gorges open to the sea in a direction transverse to the main line of the mountains. But the projecting spurs which form these gorges are not considerable in height; and on the southern or Mediterranean side the main range sinks towards the sea in subordinate or secondary ranges, more or less parallel to the principal chain, and therefore seldom admitting of abrupt headlands with deep embrasures between. There is, however, one exception. At the foot of Italy the central range forks off into two great branches, one running towards the toe of the peninsula, the other forming the heel. The low lands between these two ranges have been scooped out by the waves, and here has been formed the great Gulf of Tarentum, a vast expanse of sea, measuring from point to point no less than eighty miles. But except this great gulf, the coasts of the peninsula are indented by comparatively gentle curves. On the northern side the single inequality is presented by the projecting mass of Mount Garganus, which forms with the lower coast what is now called the Bay of Manfredonia. On the sole of the foot, below the Gulf of Tarentum, we find the Bay of Squillace (Sinus Scylacius). After passing the Straits of Messina, first occurs the Bay of St. Eufemia (Sinus Vibonensis), which is separated from that of Squillace by a mass of granitic rocks less than twenty miles in breadth. A little higher up we come to a wide sweep in the coast, known by the name of the Bay of Policastro.
That part of the southern coast which is most irregular deserves particular attention from the student of Roman history. Between the point where ancient Lucania borders on Campania, and that at which Latium begins, a distance of about 120 miles, the coast-line is broken into three fine bays, the Bay of Pæstum or Salerno on the south, the Bay of Gaeta on the north, and between them the smallest but most famous and most beautiful of the three—the Bay of Cumæ or Naples. From Cape Circello (Circeii), which forms the northern horn of the Bay of Gaeta, the coast-line runs onward to Genoa, unbroken save by the headlands of Argentaro and Piombino in Tuscany. But these do not project far enough to form any recess worthy to be named. Nor is the little Bay of Spezzia, just north of Tuscany, deserving of mention as a geographical feature.
The same circumstance which prevents Italy from abounding in deep bays and bold headlands also prevents its coasts from being studded with islands, which are but relics of projecting mountain chains. If we omit Sicily, which is in fact a continuation of the peninsula separated by a channel of two or three miles broad, and the Lipari islands, which are due to the volcanic action still at work beneath Etna and Vesuvius, the islands of Italy are insignificant. Capreæ (Capri) on the one hand, Prochyta (Procida) and Ischia on the other, are but fragments of the two headlands that form the Bay of Naples. Igilium (Giglio) and Ilva (Elba) stand in a similar relation to the headlands of Argentaro and Piombino. Besides these may be named Pontiæ (Ponza), Pandataria, with a few more barren rocks off the Bay of Gaeta, and a few even less important on the coast of Tuscany.
Except in northern Italy, which abounds in noble rivers, the narrowness of the peninsula forbids the existence of really large streams. Yet, the Apennine range, which forms on its southern side long parallel valleys, enables numerous torrents and rills which descend towards the south to swell into rivers of not inconsiderable size. Such especially are the Arno and the Tiber. Their waters are separated by the hills which terminate in the headlands of Argentaro and Piombino, so that the Arno flows northward, and enters the sea on the northern frontier of Tuscany, after a course of about 120 miles; while the Tiber runs in a southerly direction receiving the waters of the Clanis from the west, and those of the Nar (Nera) and Velinus from the east, till its course is abruptly turned by the Sabine hills. The entire length of its channel is about 180 miles. These two well-known rivers, with their affluents, drain the whole of Etruria, the Sabine country, and the Campagna of Rome.
Similar in their course, but on a smaller scale, are the Anio (Teverone) and the Liris. They both rise in the Æquian hills, the Anio flowing northward to swell the stream of the Tiber a little above Rome; the Liris, joined by the Trerus (Sacco) from the west, running southward so as to drain southern Latium and northern Campania, till it turns abruptly towards the sea, and enters it about the middle of the Bay of Gaeta, after a course of about eighty miles.
The Vulturnus and the Calor run down opposite valleys from the north and south of the Samnite territory, till they join their streams on the frontier of Campania, and fall into the Bay of Gaeta only a short distance below the Liris. Both of these streams measure from their sources to their united mouth not less than one hundred miles.
The only other notable river on the western coast is the Silarus (Sele), which descends by a channel of about sixty miles from the central Apennines of Lucania into the Bay of Pæstum or Salerno. In the foot of Italy the mountains come down so close to the sea that from the mouth of the Silarus to the lower angle of the Gulf of Tarentum, the streams are but short and rapid torrents. Of these it is said that no fewer than eighty may be enumerated between Pæstum and the Straits of Messina. The Gulf of Tarentum receives some streams of importance. The Bradanus and Casuentus (Basento) enter the gulf within four miles of each other after a course of about sixty miles. The Aciris (Agri) is to the south of these. The Siris (Sinno), notable as the scene of the first battle between Pyrrhus and the Romans, is a mere torrent, as is the Galesus upon which Tarentum stands.
The northern or Adriatic coast is almost devoid of lateral valleys, such as are found on the other coast, and therefore has few considerable streams. The Aufidus (Ofanto) in Apulia, renowned in Roman history from the fact that the fatal battle of Cannæ took place upon its banks, rises on the opposite side of the same range from which the Calor flows, and runs a course of about eighty miles. The Sagrus (Sangro) stands in the same relation to the Vulturnus as the Aufidus does to the Calor, and conveys the waters of the Fucine Lake from the Æquian hills through Samnium, by a nearly similar length of channel. But the largest river of this side is the Aternus, which finds its way from the Sabine hills into a valley parallel to the main range, and thus prolongs its course. It is joined by a number of smaller streams, and attains a considerable volume of water before it reaches the sea at the point where the Marrucinian coast abuts on that of Picenum.
The whole coast from Mount Garganus northward is ploughed by numberless torrents which descend in rapid course down steep mountain gorges. Of these we need but name the Æsis between Picenum and Umbria; the Metaurus in Umbria, famous for the defeat of Hasdrubal; the Rubicon, which formed the boundary of Roman Italy on the northern side, as did the Macra (Magra) on the opposite coast.