338 Mediceval Military Architecture. of Roman remains, but in unison with the form and character of a part of the earthworks which enter into the composition of the present castle. These appear to have been a single lofty bank raised from an exterior ditch, and enclosing much of three sides of a quadrangular space, of which the fourth lies open towards the river ; a practice by no means unusual in Roman or " quasi-" Roman encampments. It is possible, though scarcely probable, that the earthwork was once complete on the three sides down to the river, and that the south- western part was destroyed to form a very considerable mound, which still remains towering over the banks of the enclosure, and is crowned by the shell of an early multangular keep. Wallingford, Tamworth and Wareham are instances in which a quadrangular earthwork has been in part retained and in part removed by the builders of a -Norman castle, and in each of which also there is a mound. Whatever may have been its origin, the castle of Cardiff covers a plot of ground nearly square in plan, being 200 yards east and west by 216 yards north and south ; and bounded on the north and east, and partially on the south, sides, by banks of earth, and on the west and remainder of the south side by a wall. The banks are about 30 feet high, 90 feet broad at the base, and 12 feet at the summit, along which runs a light embattled wall about 6 feet high and 2 feet thick. This wall is mentioned by Meyric, in 1578, as in decay, and it was rebuilt from its shallow foundation of only 2 feet in 186 1. It cannot have been intended as a serious military defence, and the recent excavations did not reveal any traces of an older or more substantial work. At the south-east, north-east, and north- west angles, the banks are strengthened, possibly to carry towers, of which, however, no foundations have been discovered. The earthwork is returned about 70 yards along the south, and about 30 yards along the west, fronts, to give support to, and cover the commencement of, the walls of those sides which, with an incon- siderable exception, are evidently very ancient, and were probably executed by Robert, Consul or Earl of Gloucester. These walls are magnificent works, being 40 feet high and 10 feet thick, and perfectly solid. The main buildings of the castle are in the line and form a part of the west wall. In the centre of the south side is the gateway, once of the outer ward, now of the general inclosure, a mere arch in the curtain, and, in its present form, probably of the age of Henry VI I L, whose arms may have occupied a square stone frame remaining above and on the outside of the gate. Close west of the gate is a lofty tower, apparently of early English or early Decorated date, and- restored by the late Lord Bute. This is the black tower. Though so near the gate it is clear that it never had any direct communication with it, nor was intended as a gate- house. Meyric describes it as a great tower, some stories high, and covered with lead, with two chambers in each story, the lowest
