LATIUM. which must at a distant period have been the centre of volcanic outbursts on a great scale. Besides the central or principal crater of this group, there are several minor craters, or crater-shaped hollows, at a much lower level around its ridges, which were in all probability at ditl'erent periods centres of erup- tion. Some of these have been filled with water, and thus constitute the beautiful basin-shaped lakes of Albano and Nemi, while others have been drained at periods more or less remote. Such is the case with the Vallis Aricina, which appears to have at one time constituted a lake [Akicia], as well as with the now dry basin of Cornufelle, below Tus- culum, supposed, with good reason, to be the ancient Lake Regillus, and with the somewhat more con- siderable Lago dl Castiglione, adjoining the an- cient Gabii, which has been of late years either wholly or partially drained. Besides these distinct foci of Volcanic action, there remain in several parts of the Campagna spots where sulphureous and other vapours are still evolved in considerable quantities, so as to constitute deposits of sulphur available for economic purposes. Such are the Lago di Sol- falara near Tivoli (the Aquae Albulae of the Ro- mans), and the Solfatara on the road to Ardea, supposed to be the site of the ancient Oracle of Faunus. Numerous allusions to these sulphureous and mephitic exhalations are found in the ancient writers, and there is reason to suppose that they were in ancient times more numerous than at pre- sent. But the evidences of volcanic action are not confined to these local phenomena ; the whole plain of the Campagna itself, as well as the portion of Southern Etruria which adjoins it, is a deposit of volcanic origin, consisting of the peculiar substance called by Italian geologists tufo, — an aggregate of volcanic materials, sand, small stones, and scoriae or cinders, together with pumice, varying in consis- tency from an almost incoherent sand to a stone sufficiently hard to be well adapted for building pur- poses. The hardest varieties are those now called peperino, to which belong the Lapis Gabinus and Lapis Albanus of the ancients. But even the com- mon tufo was in many cases quarried for building purposes, as at the Lapidicinae Rubrae, a few miles from the city near the bank of the Tiber, and many other spots in the immediate neighbourhood of Rome. (Vitruv. ii. 7.) Beds of true lava are rare, but by no means wanting : the most considerable are two streams which have flowed from the foot of the Alban Mount ; the one in the direction of Ardea, the other on the line of the Appiau Way (which runs along the ridge of it for many miles) extending as far as a spot called Capo di Bove, little more than two miles from the gates of Rome. It was exten- sively quarried by the Romans, who derived from thence their principal supplies of the hard basaltic lava (called by them silex) with which they paved their high roads. Smaller beds of the same mate- rial occur near the Lago di Castiglione, and at other spots in the Campagmi. (Concerning the geological phenomena of Latium see Daubeny On Volcanoes, pp. 162 — 173 ; and an Essay by Hoff- mann in the Beschrdhung der Stadt Rom. vol. i. pp. 45—81.) The strip of country immediately adjoining the sea-coast of Latium differs materially from the rest of the district. Between the borders of the volcanic deposit just described and the sea there intervenes a broad strip of sandy p)lain, evidently formed merely by successive accumulations of sand from the sea, LATIL^I. 135 and constituting a barren tract, still covered, as it was in ancient times, almost wholly with wood. This broad belt of forest region extends without inter- ruption from the mouth of the Tiber near Ostia to the promontory of Antium. The parts of it nearest the sea are rendered marshy by the stagnation of the streams that flow through it, the outlets of which to the sea are blocked up by the accumula- tions of sand. The headland of Antium is formed by a mass of limestone rock, forming a remarkable break in the otherwise uniform line of the coast, though itself of small elevation. A bay of about 8 miles across separates this headland from the low point or promontory of Astura : beyond which com- mences the far more extensive bay that stretches from the latter point to the mountain headland of Circeii. The whole of this line of coast from Astura to Circeii is bordered by a narrow strip of sand-hills, within which the waters accumulate into stagnant pools or lagoor. Beyond this again is a broad sandy tract, covered with dense forest and brushwood, but almost perfectly level, and in many places marshy; while from thence to the foot of the Voiscian moun- tains extends a tract of a still more marshy cha- racter, forming the celebrated district known as the Pontine JIarshes, and noted in ancient as well as modern times for its insalubrity. The whole of this region, which, from, its N. extremity at Cisterna to the sea near Terracina, is about 30 Roman miles in length, with an average breadth of 12 miles, is perfectly flat, and, from the stagnation of the waters which descend to it from the mountauis on the K., has been in all ages so marshy as to be ainiost unin- habitable. Pliny, indeed, records a tradition that there once existed no less than 24 cities on the site of what was in his days an unpeopled marsh, but a careful inspection of the locality is sufficient to prove that this must be a mere fable. (Plin. iii. 5. s. 9.) The dry land adjoining the marshes was doubtless occupied in ancient times by the cities or towns of Satricum, Ulubrae, and Suessa Pometia; while on the mountain ridges overlooking them rose those of Cora, Norba, Setia and Privernum; but not even the name of any town has been preser-ed to us as situated in the marshy region itself. Equally unfounded is the statement hastily adopted by Pliny, though obviously inconsistent with the last, that the whole of this allu- vial tract had been formed within the historical period, a notion that appears to have arisen in consecjuence of the identification of the Mons Circeius with the island of Circe, described by Homer as situated in the midst of an open sea. This remarkable head- land is indeed a perfectly insulated mountain, being separated from the Apennines near Terracina by a strip of level sandy coast above 8 miles in breadth, forming the southern extremity of the plain of the Pontine Marshes; but this alluvial deposit, which alone connects the two, must have been formed at a period long anterior to the historical age. The Circeian promontory formed the southern limit of Latium in the original sense. On the opposite side of the Pontine ilarshes rises the lofty group of the Voiscian mountains already described: and these are separated by the valley of the Trerus or Sacco from the ridges more immediately connected with the central Apennines, which were inhabited by the Aequians and Hernicans. All these mountain dis- tricts, as well as those inhabited by the Volscians on the S. of the Liris, around Arijimim and Atina, partake of the same general character: they are occupied almost entkely by masses and groups of
