About 34 feet in advance of the great gateway was a cross wall, probably containing a second gate, and beyond it is a flight of fifteen steps, 6 feet broad, leading down into a rectangular chamber, which has had a flat timber roof, and in the opposite wall of which is a shouldered doorway, with no rebate for a door, 2 feet 9 inches broad, and 7 feet high. This opens into a low, narrow, flat-topped passage, 3 feet broad and 10 feet long, but expanded at the centre to 3 feet 6 inches, so that two persons could pass by squeezing; and at this point, in the roof, is a hole 8 inches square, evidently for the purpose of attacking them if necessary. The passage ends in a second small doorway, barred from the inside, which opens upon a bridge-pit, about 27 feet long right and left, 12 feet deep, and 10 feet broad, to a similar doorway opposite. The pit is lined with rubble below the door cills and with ashlar above, and at its west end is a hole, probably for cleaning it out, and communicating with the main ditch, of which the pit is an isolated part. Crossing over a narrow plank bridge, the further door leads through a short, narrow passage into a chamber 13 feet square, entirely of ashlar, and having, right and left, a small door, 2 feet 9 inches broad, opening upon the counterscarp of the ditch. The doorway from the bridge had no door but those of the lateral sally-ports opened inwards. In the further, or north, wall is another doorway, also shouldered, 3 feet broad and 8 feet high, the door of which also opened inwards and disclosed a very steep flight of eleven steps, rising about 8 feet in a dovetail-shaped chamber, commencing at a breadth of 3 feet and expanding to 8 feet. It is 14 feet long. The steps land on a floor, but the walls, of which the lower 6 feet 6 inches, of ashlar, are quite perfect, have so far no openings. This singular chamber is niched into the counterscarp of the ditch, and is actually within the barbican. The remains of the _Barbican_ (F) are a considerable knoll of earth, having a ditch of its own, and on its rugged surface showing traces of old buildings. This covers the head of the bridge, and appears to have been approached by a winding road and entered on the west side. This work has been the subject of much speculation. That it was the main entrance is sufficiently certain. This could only have been at one end of the main ward, and the remaining jamb is too large for a postern, and the ground at the opposite end far too steep for an approach. The spur-work, with its lateral curtains, completely enclosed the entrance. The steps to the bridge are modern, but must represent others somewhat similar. The doors and passage were calculated for single files only, with a special arrangement for commanding the only point at which two armed men could pass. In the chamber beyond the bridge 80 or 100 men could assemble previous to a sally by the lateral doorways.