The outer ward no doubt occupies the site of an earlier outwork. It is built against the narrow and north end of the inner ward, is four-sided, about 250 feet north and south, by a mean of 110 feet east and west. Its west side is straight, being the continued line of that face of the old fortress. The east face has a slight re-entering angle, caused apparently by the shape of the ground. At the two southern angles are two large drum towers, which connect the old and newer work, and probably replace two smaller and older towers. These stand in the line of the old ditch, and flank the Norman gateway. That to the south-west, rather the larger of the two, and slightly oval in plan, has a mean diameter of 60 feet; it is of two stages. Both are vaulted, or rather domed. That to the south-east, of 50 feet diameter, is nearly circular, but has a remarkable spur or keel-shaped projection towards the field. It is of three stages, the two lower being domed. These towers are in fact casemates, having embrasures for small culverins towards the field. Each has a well-stair in its southern side, and is entered from the gorge.

The two other towers cap the northern angles of the ward, and flank the main gateway. They are of irregular form, semicircular to the field and angular within. In diameter they are about 40 feet, and about the same height. They are of two stages, which have been domed. The walls of these four towers are from 14 feet to 16 feet thick. They are of flint faced with brick.

Between the gate-tower is the gateway, composed of a larger and smaller portal, the latter very narrow. The present work is modern, but no doubt in this double entry represents the earlier openings. The ditch, two detached piers standing in it, and with these any traces of the drawbridge, are concealed by the modern causeway.

In the west curtain, near the south-west tower, a flight of steps beneath hanging arches of brick descends from the ward level in the direction of the foot of the wall. This is much encumbered with ruin, but seems to have been a postern, opening upon the ditch.

All the works of this outer ward are of flint, rubble-faced with brick, which material forms the lines of the embrasures. The quoins are sometimes of ashlar, as are the extensive string-courses and bands, and the dressings of the openings. Traces of herring-bone work in its west curtain, outside, will be accounted for afterwards.

As the original castle was confined to the inner ward, its ditch everywhere encircled it. When the outer ward was added, the intercepted portion of the ditch was partially filled up, but the new work was included in a new ditch, which was an accurate prolongation of the old one, of equal depth and breadth, and continued in the same direction. Accurate observation will, however, detect two slight shoulders in the counterscarp, showing where began the curve of the old ditch.

Very remarkable in this castle are the subterranean galleries, driven in the chalk rock beneath the lines of the original wall, and behind the scarp of the ditch. These are now in part blocked up, but there still remain two or three hundred yards of them of which the direction is known. They are entered by a passage in the inner ward, in its north-west quarter, and by a descent of fifty-four steps near the keep, and possibly from other points now lost. The galleries are about 7 feet high and 6 feet wide, rudely cut, and somewhat singularly laid out. They lie within, without, and beneath the wall, and give off frequent spurs or short passages intended to occupy any space in which a mine was likely to be opened. At this time they have been broken into at three or four points in the scarp of the ditch, about half-way down. They were intended as a system of permanent counter mines to meet any attempt at mining on the part of the besiegers. In one place a large central pier is surrounded by a gallery, whence the branches go off,—an arrangement intended probably to check the progress of those who might break in. So far as is known, these galleries, of which a survey was made in 1708, are confined to the southern half, or four-fifths of the old castle. There are none under the outer ward.

Outside, and to the north-east of the outer gate, are some semicircular platforms, which seem to have played a part in the defence of the castle; but whether before or after the use of artillery is uncertain.

The Bel.—A curtain wall, which originally was about 5 feet thick, and from 15 feet to 20 feet high, commences abruptly upon the crest of the counterscarp in two places; one on the east opposite to the mural tower, which marks about the centre of that front of the castle, and thence descends towards the river; and the other north, close outside of the drawbridge of the main entrance. This latter wall is continued down the hill, and makes a bold sweep towards the town, and, finally reaching the river bank, joins the river wall. The enclosure thus formed contains about twice the area included by the ditch of the castle, and has long been known as Le Bel or La Baile, a form evidently of the Norman-Latin Ballium, called by us the “Bailey.” This enclosure is traversed by the road from Dieppe to Martigny, which passes through the two gates bearing those names. A third, or water-gate to the east, opened upon the river. Upon the north front appear to have been two small half-round mural towers, of which one remains. The river has somewhat encroached upon the lower part of the Bel, and has undermined part of the wall.

The Dieppe gate, which is also that from the town of Arques, was in 1433 called “La Première Port du Bel de Château d’Arques,” and, as such, was the subject of a tenure by castle guard, the tenant being bound to defend it for forty days in time of war. From this gate the approach ascends to the castle, having the curtain-wall as a protection on its right. Where this wall approaches the castle, at either end, it is covered by a broad ditch, continued down the slope.