The lower 10 feet of this tower is solid, and above this are two stages. The basement, now a cellar and boot-hole, is of irregular plan, and may be called a rectangular figure with inclined ends. The walls are from 9 feet to 13 feet thick, and contain four pointed arched recesses with loops, and a mural chamber, also looped. The entrance passage from the gorge is bent at right angles. This chamber is vaulted and ribbed, its outer end terminating in a rude pentagon, traversed by five hip-ribs, of plain rectangular section, and meeting by a high-pitched arch, in a central boss. This boss and the capitals whence spring three of the ribs are of early English character. The shafts are wanting. The upper chamber is rudely circular, and about 18 feet across. The walls are 8 feet thick. From the well-stair, which commences at this level, a short passage opens into a rectangular lobby, also vaulted, 4 feet by 5 feet 6 inches, from which a door leads into the chamber, and another into a small flag-roofed mural gallery, which threads the south wall for 22 feet, and has two loops, one raking the south curtain, the other lighting a garderobe, which seems to have another opening direct into the tower. The main chamber was lighted by four loops, of which two have been converted into windows, and two stopped up. These recesses are of irregular breadth, with high drop arches, the crowns 10 feet 3 inches from the ground, with traces of a broad moulding above each. The north loop rakes the west curtain, and has cupboards right and left under flat drop arches for archers’ tools. Another has a lateral squint towards the south, and another, with a hole in its arch, widened by the rubbing of the old bell-rope, has evidently been used as a doorway. No doubt it opened upon the gatehouse, now removed, which crossed the outer ward at this point, close north of the Byward gate. This chamber is rudely domed in with overhanging courses of tile stone and flat rubble, like an ancient dovecote. No doubt a proper vault was intended. To the spring of the dome is 14 feet, to its crown 22 feet. It was in this chamber that, in 1830, was discovered an inscription commemorating the imprisonment here, 20th June, 1565, of Lady Mary Douglas, Countess of Lennox, on account of the marriage of her son, Lord Darnley, to the Queen of Scots. The well-stair ascends from this floor to the battlements; and at its foot a narrow door, set in a square recess, opens upon the rampart wall of the west curtain, leading to the Beauchamp Tower. The Bell Tower has been the subject of an interesting paper by the Rev. Thomas Hugo, read in Suffolk Street, in 1858. It may safely be attributed to the reign of John, or even of Richard I., that is, to the last twenty years of the twelfth century.