The east curtain is, for the most part, a mere wall, 8 feet to 10 feet thick, and 10 feet to 15 feet high, exclusive of battlements, and more or less ruined. Loops are to be seen on its exterior, directed downwards so as to rake the scarp. Near the Horseshoe Tower was formerly another mural chamber, called a stable, but more probably a garderobe, and beyond this is a large arch, now walled up, which may have been a postern, and commanded by the Plukenet Tower.
This is a mere half-round mural tower, solid to the rampart height, and of no projection within.
Above the rampart it is hollowed into a chamber open behind, with three loops, each 5 feet 6 inches long and 2 inches in the opening. In each of the recesses, on the right, is a small cupboard for the grease or tools needed by the archer. The tower and rampart were ascended by a well-stair on the north or upper side. The arrangements for allowing the archer to shoot downwards so as to rake the steep scarp are well seen here. This tower is named from a bold and well-preserved shield upon its outer face, charged with a bend fusilly, or five fusils conjoined in bend, and held up by two hands which emerge from holes in the stone. This is one of the well-known coats attributed to the Mareschals, Earls of Pembroke; but, as this family was extinct half a century before the date of this tower, and does not appear ever to have been connected with the castle, Mr. Bond has shown it to be more probable that the shield is intended to commemorate Alan Plukenet, constable of the castle in the 54th of Henry III., and a baron in the reign of Edward, his son, and whose arms were either a bend engrailed, or fusilly, represented anciently much in the same way, upon a field ermine, which fur (as Mr. Bond suggests) may have been regarded as a tincture, the lines for expressing which were not then employed, and the spots omitted by the carver.
The curtain from this tower to the Gloriette angle of the inner ward is constructed of much larger stones than those employed lower down. They are as large as many of those in the Norman ashlar, but of ruder workmanship.
Returning to the gatehouse and following the west front, this commences with a short curtain, still standing, and connected with the first mural tower, a drum of rather above half-round projection, capping an angle. It is solid to the rampart level, and above this open at the gorge. Its single chamber has three loops, cruciform, and shorter, wider, and of coarser construction than those of the Horseshoe Tower, though still of excellent ashlar. This tower having been riven by powder is seen to be 10 yards in solid thickness. Its base is perforated by a rude rectangular drain, 18 inches by 12 inches, joined by other drains of 9 inches by 9 inches, all in the solid, and evidently descending from garderobes, one of which seems to have been placed in the curtain close north of this tower.
Next above this is the second or Well Tower, so called from a small depression behind it, said to indicate a well. This tower resembles the last, was, like it, solid in the base, and had one chamber on the rampart, open at the gorge and pierced by three loops.
Close south of it was a small doorway, leading either to a garderobe or a rampart stair. Of this, one jamb is alone seen.
Above the Well Tower is the third, and above the third, and also connected with it by a short curtain, is the fourth of these mural towers. This, however, though a tower, is of the nature of an épaulement, or redan, and caps a projection or shoulder of the curtain. It has but two loops, longitudinal only, one towards the field and one raking the south wall. The former is divided into a short upper and long lower part by a narrow plate of stone, which projects inwards like a shelf.
The curtain from this Redan Tower to the gateway of the middle ward is probably earlier than either, and is very lofty. It traverses King John’s fosse. It is constructed of large stones, and resembles, in some respects, the curtain above the Plukenet Tower, at the other end of the same fosse. Below it is solid, above it is pierced by four rude loops, boldly splayed within, and which must have opened from a chamber, of which the curtain was the outer wall, or possibly from a wooden platform.
The fosse, attributed to King John, which traverses the outer ward, is about 20 feet deep, with a vertical counterscarp cut in the chalk rock. The Plukenet Tower and adjacent curtain cross its east end, but these stand upon a ridge of solid rock, showing that the ditch has never been continued into the front in this direction. At its west end the case is different. There it has been cut right into and down the slope, and the curtain crossing and stopping it is built actually in the ditch.