178 NORTH-WEST AFEICA. which has been laid bare is no less than 33 feet thick, affording room for five or six chariots to pass abreast on its flat top. Recesses were hollowed out in the thickness of the wall, which doubtless served as magazines and retreats for the garrison. The whole of this structure is as hard as the most compact rocks ; the Roman walls erected on Punic foundations are much less solid, and are easily blown up by gunpowder. The other relics of those days, even those hidden under heaps of more recent ruins, have also been destroyed or converted into shapeless masses. In fact, " Tunis and its environs have no other quarry than Carthage. The Arabs are as industrious as moles in undermining the ground ; they proceed beneath it by subterranean passages, and follow along the walls which they demolish and carry away without thinking of what they are destroying." There still existed quite recently a corporation of "stone- seekers." In the Middle At'es the Italian republics caused the ruins of Carthage to be sj'stematically excavated to provide building materials for their own edifices. According to a tradition the city of Pisa was built entirely of marbles brought from this Punic citv. The materials now used in building the surrounding towns and villages are procured from the vast brickfields of Carthage, which lie at the foot of the Bu-Said hill. East of the Byrsa terrace, on the gentle incline of the hill, are the best pre- served of all those cisterns which served as reservoirs for the water brought down by Adrian's aqueduct. Unfortunately deprived at their eastern extremity of the earth embankment which protected them from the inclemency of the weather, they are on this side partly choked up by the remains of vaults, but to the east they are still quite perfect. The rain water which percolates through the soil is here preserved perfectly pure, and from this source the Arabs still draw their supplies. The project of repairing the cisterns of Carthage has often been mooted, with a view to provide Goletta and Marsa with water, and this work, of such urgent necessity, will doubtless be undertaken in the near future. The whole of the Byrsa reservoirs would hold 750,000 cubic feet of water, more than the combined capacity of all the others situated along the Zaghwan aqueduct. The cisterns of Malka have been changed into dwellings and caves by the Arab troglodytes. The old Carthaginian ports, constructed on the site of the first Punic colony, are also easily recognised, although the entrance is obliterated and the military port no longer communicates with the commercial basins. Archaeologists have discovered in the alluvial soil Avails and quays, by which their original form may be conjectured, and the island on which the admiral resided is still to be seen in the centre of the northern basin. But it would be quite useless to attempt to restore the port of Carthage, because modern shipping needs basins with wider entrances and far greater depth than the old galleys. Hence, were Carthage ever rebuilt, as has often been proposed, a new port would have to be constructed, not inland, but in the open sea. A jetty, based on the last spur of the rocky hills at Goletta, would stretch directly southwards to depths of over 30 feet, in such a way as to enclose a vast sheet of water, which, even without artificial shelter, would be always calm, thanks to the protection afforded by the Bu-Said headland from
