Along the north front the ground, though very steep, is not absolutely precipitous, and along the crest of the slope are the remains of the curtain wall, about 6 feet to 9 feet thick, and in parts 20 to 30 feet high. Upon this wall is a rectangular tower, about 12 feet by 20 feet, having a ground and upper floors in which are parts of three windows of Norman date. Connected with this tower are said to be traces of a small postern, and there is certainly a mural passage, 18 feet long, ending in a garderobe. East of this tower is a turret, square at the base, but which above seems to have been cylindrical. It contains a well-stair connected with the chapel. The wall is continued round the east front across to the cliff. At the angle it is still 20 feet to 25 feet high, but further on it has been reduced to 10 feet. In this front, overlooking the ditch, are the bases of three half-round buttress towers, 20 feet diameter. Their ground floors have been vaulted; all above is removed. Between the two most northern of these are still to be seen the jambs of an Edwardian gateway, of 9 feet opening, with a square portcullis groove, and rebates for a door immediately behind it. In this part of the curtain are the remains of some mural cells. The gateway must have communicated with the outer ward by a bridge across the ditch, probably of timber, since there is no trace of masonry in the rock. This entrance is now disused, and the entrance in use is in the north side between the chapel tower and the north-east angle, protected by a late tower, about 20 feet square with very slight walls and a flanking wall, also slight, and projecting about 20 feet. This is thought to have been the original gateway of the ward, and may have been so, though the other entrance between the two flanking half-round towers has at present more the aspect of a main entrance.
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.
The chancel was about 18 feet broad by 28 feet long. Of its walls only a few traces remain. It communicated on the north side with a small chamber, perhaps a garderobe, and on the south side with the vestry. The vestry, called also the chapter-house, is a small, nearly square chamber, 12 feet by 15 feet, with a plain Norman recess in its east wall, and the jambs of a door, evidently Norman, opening into what seems to have been a sort of lean-to cloister resting on the south wall of the nave. The cloister itself is gone; but in the nave wall are traces of an arcade. Here are three graves inclosed in pieces of stone placed edgeways, and a much worn dos-d’âne coffin-lid. The breadth of the nave is wide for a single span, but if there were aisles, there must have been two, the arches being central, and in that case very narrow ones, even for a Norman church. The floor of the chancel is three steps above that of the nave.
The curtain wall along the north front and over the mound is apparently of Norman date, as is most of the east wall; but its buttress-towers and the gateway are probably insertions of the reign of Henry III. or Edward. The chapel may be later than the north wall, probably of the reign of Henry II. or John.
The old part of the masonry is coursed rubble, with occasional pebble-stones, faced with bold, open-jointed ashlar, the blocks being rudely dressed. In one part, near the church, is a little herring-bone work, though probably not older than, if so old as, the rest. The quoins and window-dressings, where preserved, are good ashlar. Various fragments of cut stone are collected and heaped up; of these, a few are late Norman, some good early English, some Perpendicular. A late Norman crypt has been discovered in the town.
It may be doubted whether William or his feudatories, the Earl of Eu or de Tiliol, added defences in masonry to the works already existing. At least, there is no evidence that they did so, and the oldest masonry now seen is certainly not very early Norman, though too early to have allowed time for the decay of any previous masonry of the same architectural period.
The chapel was probably founded in the reign of Henry I., and though the castle was erected, and for some time held, under the Crown, by the powerful Earls of Eu, it was never a great baronial residence, being in that respect far inferior to Arundel or Lewes, but was probably maintained only as a strong, though small, post to cover embarkations for, or disembarkations from, Normandy.
The Outer Ward is contained between the inner and outer lines of ditch; within the latter is a considerable bank of earth, which rises at the north-east angle and is continued across the northern end, that being naturally the weakest part of the inclosure. It does not appear where was the entrance of this ward, but possibly near the south-east angle. There are no traces of masonry here, so that the defences of the outer ward may have been a stockade only.