The four faces of the keep are generally alike. Each is flanked by two pilasters of 4 feet 6 inches wide, by 9 feet projection, so placed as not to cap the angle, but to convert it into a hollow or re-entering one. This hollow was left open, not filled up, as at Scarborough and elsewhere, by a bold bead or engaged column. In the centre of each face is a third and similar pilaster, but 5 feet wide. Probably these rested below upon a plinth common to the whole building; but if so, this is gone. Each pilaster is of equal breadth and projection throughout, having no sets-off. The central pilasters run up to the base of the parapet, now gone. Those at the angles were continued to form the usual square turrets, of which some slight though clear remains still rise above the curtain. The material employed for the exterior is chiefly Bargate stone, from the bed representing the chalk marl immediately beneath the chalk. This is worked up as rubble, interspersed irregularly with courses of the same stone laid herring-bone fashion, for which the larger and flatter stones have been selected. The work is very rough. The herring-bone courses are laid at all heights and distances; some broken, some mere single inclined stones, and here and there, especially near the top, are occasional courses of flints, some of which look like insertions. The angles, salient and re-entering, of the pilasters, are of the same stone, cut as ashlar and well jointed; but between these quoins the pilasters are usually of rubble, sometimes herring-boned. Above the parapets the angle turrets seem to have been of ashlar. There is no string-course, shelf, or set-off upon the face of the wall. The west-central pilaster, being pierced by the entrance, is mainly of ashlar, as are the pilaster and adjacent wall, about the north-east angle of the building, where the gate of the ward seems, from traces in the masonry, to have abutted. Here, too, the joints being very wide are made good with single or double rows of thin ordinary bright-red roofing tiles. The base of the east face was repaired about forty years ago, and now has a modern ashlar plinth of about 15 feet high. The ashlar within reach on the other faces has been pillaged, and the base of the wall generally is very hollow and ragged. The hearting of the walls throughout seems composed of chalk and Bargate stone, very roughly laid and grouted.