It may be well to give here a general description of the Norman work, taking the nave first, as being the most important feature in the whole great scheme. The nave consists of three double compartments, a single bay westward of these, and the western bay flanked by the towers. The principal piers consist of triple shafts, placed on each face of a central mass, square in plan; the shafts rest on massive bases of cruciform plan, having a flat projecting band about the middle and a narrow plinth at the bottom. A similar band and plinth are carried beneath the wall-arcades of the nave and transepts and entirely round the church on the outside. In the choir, however, except on the piers of the tower arch, the bases are without a band, but have a plinth of greater height, the responds on the aisle walls being similar. The triple shafts next the nave or choir rise almost to the top of the triforium, and support the great transverse arches of the vault. The shafts next the aisles receive the diagonal and transverse ribs of the aisle vault, and the shafts on the two remaining faces receive the arches of the great arcade. The intermediate piers, in the centre of each double compartment, are circular in plan, and stand on square bases. The western pair of piers, at the corners of the towers, are clustered like the other main piers, but have two additional shafts (like the crossing piers), but these shafts on the side next the nave receive the diagonal ribs of the vault, whereas the additional shafts on the crossing piers support the outer order of the tower arches. The triforium is of eight bays, having a containing arch with two sub-arches, the tympanum being solid. The clerestory has in each of its eight bays a lofty and wide arch with a smaller and lower one on each side, the central arch having a window fronting it. It has a wall passage which connects it with the clerestories on the west side of the transepts. The inner arcade in the eastern bays appears to be an insertion, possibly made when the vault was put on the nave. The idea of vaulting the nave was apparently abandoned, when the triforium stage was reached, and it is probable that the arrangement of the nave clerestory was at first not unlike that of the south transept. The resumption of the vaulting idea thus necessitated an alteration in the design of the clerestory. The nave is covered a double quadripartite vault over each double compartment, without transverse ribs over the minor piers. The great transverse arches, which spring from the major piers, are pointed. The diagonal ribs, which rise from corbels inserted in the spandrils of the triforium arches, are semicircular. They are all decorated with zigzag.