Between the windows are clusters of shafts which support the ribs of the vault. These shafts have fine capitals, and are separated from the windows by blank spaces of wall set at an obtuse angle to the windows, so that the shafts are pushed forward. Below is an arcade, famous both for its richness and curiously beautiful design. It consists of a series of canopies, six to each bay, under each of which is a seat forming the half of an octagon. At each angle of these seats is a shaft of Purbeck marble. The seats, or niches, are divided from each other also by shafts of Purbeck marble. The use of Purbeck marble, both here and in the doorway of the chapter-house, is worthy of note. It is unusual after the Early English period, and might be advanced as an argument of the early date of the chapter-house. In the bay which contains the entrance, there is a seat on each side of the doorway. The capitals of the Purbeck marble shafts are carved with unusual richness; but it is the canopies which demand most attention. They are flat at the top, and each is divided into three bays in front, the central bay being divided from the other two by pendants richly carved with foliage of the same character as the capitals of the shafts. Between the shafts and the pendants are trefoil arches, one to each bay, and above the arches and pendants are gables crossing each other and ending in finials of carved oak leaves. Where the gables cross each other are carved heads and figures. The sculpture of the arcade as a whole is the finest in the cathedral, and some of the finest in England; but the art of the Gothic sculptor reaches its culmination in these heads. In grotesqueness, fertility of invention, and perfect fitness as decoration they could hardly be surpassed. The canopies are decorated at the top with a cornice of carved grapes and vine leaves. Above them is a passage running round the whole chapter-house and passing behind the vaulting shafts and through the masses of masonry between the windows. The vault is of wood, though ribbed and painted to give it the appearance of stone. This vault is arranged so that the ribs diverge from the vaulting shafts until they reach the central octagon of the roof. At this point they converge to the boss in the middle of the central octagon. This boss is modern. The roof was restored in 1845. Before this time it was painted with figures of kings and bishops, and the bosses were covered with silver. The modern decoration of the roof is dull and trivial in design and offensive in colour. During the same restoration many of the marble shafts were replaced and the floor was paved with tiles, with a most unfortunate effect. The east window has also been filled with very bad modern glass. In fact, restorers have done their worst to the chapter-house; but, luckily, their work is not irreparable. We may hope that some day the glass, the tiles, and the paint on the roof will all be removed.