There are also projections on the west and south wall. That on the west has a depth of 12 feet, and a breadth of 18 feet. The lower story is broken away; it was hollow, and looks as though meant for a gigantic cesspit. The upper part hangs unsupported save by the cohesion of its cement, and greatly needs conservation. This turret is about 51 feet from the north end, and 31 feet from the south. The projection on the south wall is 12 feet broad, and 8 feet deep. It is placed 24 feet from the west, and 44 feet from the east angle, coinciding with the partition-wall within. This turret is hollow, and forms a great shaft for garderobes in the upper stories. In its face, at the ground level, is a round-headed arch, of 3 feet opening, and 4 feet high, the outlet of the sewer, but above ground. These two turrets at present cease at the level of the parapet, but probably rose sufficiently above it to cover a garderobe. The keep has a plinth on the north, west, and south sides. The east face is covered by the fore-building. The walls are about 9 feet thick.
The keep has a basement floor at the ground level, and a first or state floor, and on the east side an upper floor. It is divided by a wall 9 feet thick into two unequal parts, that to the east being 29 feet, and that to the west 24 feet broad, each being about 84 feet long. A well-stair 12 feet diameter, ascended in the south-east angle from the basement to the battlements, lighted by loops, and with doors to each floor.
The east chamber into which this stair opens by a large and apparently round-headed door, now broken, was vaulted in two lines, each resting upon five cylindrical piers, about 3 feet 6 inches each in diameter, and averaging 14 feet from centre to centre. The vault seems to have been a barrel, groined. At each end were two square-headed loops, high above the floor, with stepped recesses. The east wall contains only three square lockers, and the door of the staircase. The west or partition-wall side is pierced by five openings, about 4 feet broad, and round-headed, three to the north and two to the south of the thick solid central part. Probably these were introduced to lighten the work, and all but one or two thinly walled up. One must have been a doorway, as from the eastern lay the only communication with the western chamber.
The western chamber seems to have been spanned by a single vault, apparently slightly pointed and groined in six bays. In each end is a single square-headed loop. On the west side are seven loops, the central part being occupied by the unpierced rear wall of the turret already described.
First floor, east side. This was evidently the hall. It is very lofty, and in its north end is a round-headed window of 2 feet opening, and 7 feet high to the springing. In the south end are two similar windows, but about 14 feet long, and a curious water-drain between them and the door. This, the door from the stair, is plain round-headed, and of 6 feet opening. Close north of it is a similar door, of 7 feet opening, quite plain, and without a portcullis. This is the main entrance, and opens from the barbican tower. Beyond this is a short window, and then three long ones, like those at the north end, so arranged as to open clear of the exterior barbican stair. The west wall has an opening at each end, the bulk of the wall being solid. The northern of the two openings was probably the great door of passage between the rooms; the southern communicated with the garderobe in the south wall. In the north-east angle is a very curious mural chamber, 12 feet east and west, by 9 feet north and south, vaulted in a single groined bay, round-headed, and springing from half-octagon brackets in the angles, each the cap of a detached shaft, now removed. In the north wall are two and in the east one loop. A door in the south wall opens into the north end of the hall, and one in the east wall passes obliquely through the wall, and evidently led to the battlements of the outer gate of the barbican, over the foot of its staircase. This room is much broken, but its fittings are original, and late Norman. If the hall had a fireplace in masonry, it was in the west wall, at a part recently repaired. It is not clear how the hall was roofed; possibly the original covering was a high-pitched roof, with the battlements above, but at present the side walls carry a table, with corbels of a plain billet moulding, on which an upper wall, about 12 feet high, is advanced 6 inches. In these walls are large window openings, with segmental arches, three on each side, which must have opened clear of the roof of the west chamber, and upon the battlements on the east side. In the south end, above the two narrow windows mentioned, is a third smaller one, as though to light a roof of high pitch. There are no corbels for principals, and no holes for main beams, but above the corbel table on each side is a range of holes, about 9 inches square, and as much apart, neatly stopped with ashlar, as though an original flat roof had been removed, and a roof of high pitch introduced. However this may have been, the windows of the side walls are clearly additional, and belonged to a second floor. Altogether the history of this roof is very obscure, and demands a close local investigation. The upper door in the well-stair is not at a level to suit a second floor, nor consistent with a high-pitched roof.
First floor, west side. In the north end is a round-headed window, 2 feet opening by 7 feet high, and a door into a now inaccessible mural chamber in the north-west angle. At the south end are two similar windows, and a door into a chamber in the south-west angle. In the east wall are the two broken doorways already mentioned, and the broken tunnels of two, if not of three, large fireplaces, the shafts of which, much broken, still rise clear of the roof. The fireplaces are gone, and the wall has been much patched recently to give it support. There are two rather curious lockers in this wall. In the west wall there seem to have been four round-headed windows of 2 feet opening and 7 feet high, and near the middle is a door opening into the middle buttress tower, which contains two chambers of unequal size. These are not accessible, but one was probably a large garderobe, and the other may have been the way to a small drawbridge, opening from the keep upon a rectangular tower in the ward, not 12 feet distant, so as to give direct passage from the keep to the outer walls. In the keep wall, north of this tower, is a large segmental-arched window, evidently an insertion, probably the work of Richard III. In the north-west and south-west angles, as already mentioned, are mural chambers, not accessible. There do not appear to be any galleries in the wall.
This west chamber was probably divided by a brattice, and the north part used as a withdrawing-room from the hall. There does not appear to have been a second floor on this side. It is, however, curious that there should be no corbels, nor any of the usual indications of the principals of an ordinary open roof. In each side wall, high up, is a row of holes, about 9 inches square and 18 inches from centre to centre, so that probably the roof was flat, or at any rate, was composed of heavy rafters, without principals.
The east face of the keep was occupied by the fore-building or barbican, and which, as was not uncommon, contained the chapel.
The approach seems to have been, as at Rochester, Scarborough, and elsewhere, by a flight of stone steps built against the wall, commencing, in this case, about 10 feet from its northern end, and rising about 20 feet to a vestibule, upon which opened, right and left, the great door of the keep, and that of the chapel. The staircase was about 9 feet broad, and 45 feet or 50 feet long to the vestibule. It seems to have been protected by a side wall, reducing the actual stair-breadth to (say) 5 feet or 6 feet, and to have been either vaulted or roofed with timber. Its lower gate must have opened beneath a small tower, the battlements of which were reached from the chamber in the north-east angle of the keep. About half-way up the staircase past what, from the appearance of the wall, seems to have been a second gate in the keep wall, is a large cavity capable of holding comfortably twenty men, evidently as a guard in case the entrance should be forced. Higher up, where the staircase landed on the vestibule, there seems to have been a third door.
The vestibule is part of the second floor of the usual rectangular barbican tower, built against the keep, about 12 feet from the south end of the east face. This tower measures about 33 feet north and south, and about 48 feet east and west. It rose about two-thirds of the height of the keep, and is divided into a basement or sub-crypt, an upper crypt, and a chapel and vestibule floor.