The eastern, naturally the weakest side of the inner ward is further defended by a broad, artificial bank or ramp of earth from 20 feet to 30 feet broad and 8 feet to 10 feet high, piled up against the back of the wall, which, in fact, is a revetment. At the north-east angle of the ward this bank is expanded into a mound about 20 feet high above the inner area. The curtain traverses this mound, of which about two-thirds is within its circuit. No doubt this mound was the keep of the English fortress, and the bank and ditch its main landward defences, but, save the curtain, there is no trace of any masonry upon it, nor does the Norman castle appear to have been provided with any regular keep, either shell or rectangular. Probably, as at Exeter, the whole inner ward was the keep. There are at present no traces of a hall, kitchen, or regular lodgings within the castle, but placed against the north wall are the remains of the chapel, or rather of the free collegiate church, composed of a nave and chancel. The nave was 30 feet by 64 feet, the curtain forming the north wall. There seem to have been a west door and one, or perhaps two, south doors. At its east end a handsome highly-pointed arch opened into the chancel, and still remains very perfect. The jambs are square, the angles replaced by delicate shafts, a quarter engaged, with caps and bases of Norman type. The abacus is part of a moulded string, and the arch, though the section is square, as in the Norman style, is richly moulded. The central member of the arch is a bold rib, springing from two brackets or corbels carved in foliage. The general character of the whole is very late Norman, passing into early English. In the north wall, at its east end, are the remains of the arches of three sedilia, and near the middle of the wall, in a sort of buttress, is a piscina, probably a perpendicular insertion. Near the north-west angle is the cylindrical base of the font. In the east wall, on each side of the chancel arch, is a flat-topped doorway of rude workmanship, as though intended to be concealed by hangings. The northern door opens into the well-stair of the turret, the southern into a vestry.