North of the platform a curtain wall runs from the gatehouse up the mound, with the summit of which its top is level. This wall in plan is angular, or slightly convex, towards the exterior or town side. It is 10 feet thick, and has a rampart wall of 7 feet, a parapet of 2 feet, and a rere wall of 1 foot. The rampart walk or allure was probably the only way from the gatehouse to the top of the mound. It rises gently, but has no steps. It is about 20 feet high at the central part, ending and commencing at nothing. It is of herring bone masonry, of flat stones laid obliquely on edge, each course being separated by a horizontal bed, sometimes single, sometimes double, of small stones, resembling flat pebbles. At the deepest there are twenty-one courses. Here and there the surface has been patched, but on the whole the wall is in its original state, very rough, but perfect. The joints are very open. The exterior face is less perfect, and is, besides, concealed by clumsy buttresses, perhaps of Tudor or earlier date. The herring-bone structure is not seen in the rere wall, which is probably a restoration, but it appears in the front parapet for a foot or two above the rampart walk. This is a very remarkable wall, and should be photographed in detail.

The continuation of the wall to the upper lodge or gatehouse from the town is in part old, but of later date than the curtain. The gatehouse itself is chiefly modern, but part is old; and connected with it are the remains of an arch jamb and portcullis groove, probably traces of the main entrance to the castle. This gate leads by a short lane into the market-place. The lower lodge, or entrance from the bridge side, was built in 1810, and with its adjacent wall is wholly of that date.

The mound is crested by a many-sided shell of wall, about 9 feet thick, and from 30 feet to 40 feet high. This wall is in part very old. The base has been supported by a modern facing, which batters considerably, and is about 2 feet high; but above this, for 6 feet or 8 feet, the workmanship is open-jointed rubble, with stones of large but irregular size and shape. The quoins are, however, of ashlar, rude but sound. Above this to the rampart height, the wall seems to have been rebuilt in early times in a better manner, but as though the old work had been left where sound, so that the two run much into one another.

The upper 10 feet of the wall, all parapet, seems of still later date. It is crenellated, and occasionally looped at the rampart level. At the south-west quarter is a loop about 6 feet from the ground, and two others higher up, all which are apparently of the age of the wall, and being near the well probably lighted the offices. This wall is much obscured by ivy. It has been materially altered at two points; on the south side entirely rebuilt for several yards to form the outer wall of the southern private apartments; and on the opposite side by the insertion at the same time of several large late Tudor windows, to light the northern apartments. Under these latter are three heavy masses of stone-work to support balconies. One is of somewhat earlier date and of better design than the others.

In the circuit of the wall, to the south, and commanding the way up the curtain, is a tower 24 feet square, and having 5 feet projection from the wall. Its angles within are plain, but those without are flanked by two narrow pilaster strips, leaving a free angle between them. These strips rise about 20 feet, and clumsily pass into a sort of octagon, which at the top of the tower becomes a cylinder, and is so seen on the battlements. These, however, may be an alteration. The tower is about 40 feet high, and the walls are 7 feet thick. It somewhat batters. On its exterior face are two Tudor windows; and about half-way up a string-course, stopped by the pilasters, which in the centre rises as a half-round drip, probably once heading a Norman window. This tower is of rubble, of the date of the wall, with ashlar pilasters. In its outer wall is a very serious crack, which seems to be getting worse.

A few feet south of the tower, and therefore close to the curtain ascent, is the doorway into the keep. This is of small size, with an equilateral arch, plain square jambs continued up through the arch moulding, which is very plain, the angle only being rounded off. The drip, if one there was, has mouldered away. This doorway traverses the wall rather obliquely. The inner front has a ribbed head, and two faces carved upon it near the springing. There is neither portcullis groove nor large bar hole. The defence was a single door.

Between the door and the tower a sort of oriel has been corbelled out at an early period, possibly to defend the approach. At present it has a loop in its basement, and two Tudor windows above, and is surmounted by a small gable of the same date.

Round the base of the wall is a terrace, about 10 feet wide and 8 feet high, above the slope of the mound. The retaining wall is in part old, and is supported by short stout buttresses, apparently of Decorated date. This wall has been patched, and in places rebuilt, in Tudor and later times, and its low circumscribing parapet is mostly modern. What it was, or when constructed, is uncertain. It may have carried a low parapet, a sort of chemisette, defending the base of the keep wall, and intended to supplement the ditch at the foot of the mound. In the last century it was crossed on the south side by a wall, with a gate in it, but this probably was not original.

The buildings within the shell are next to be described. The entrance lies beneath a sort of gatehouse, of the date of the other buildings, having on the right the tower court, and on the left a small court having the outer wall for one of its sides, and in that wall a small doorway, whence a mural staircase ascends, winding with the wall, to the battlements. The inner entrance, opening to the private apartments and hall, is a rather elaborate doorway of the style of James I. This opens into a passage or lobby, having on the right the great hall, on the left a buttery, or modern housekeeper’s room, and in front the way to the kitchen.

The hall lies north and south, and occupies nearly the centre of the enclosure. At each end of it are distinct suites of apartments, having no direct communication save through the hall. On its east side is the tower and tower-court; on its west side the kitchen and kitchen-court.