The main piers consist of a circular column, five feet in diameter, with smaller attached half-columns on three sides to carry the moulded arches between the main piers and the arches between the latter and the aisles.[423] "The piers have caps of the usual Norman modified cushion pattern, and the arches were moulded and arranged in several orders. The arcade immediately over the main arches has a row of single round shafts, with spreading Norman caps, which carry a series of moulded arches, occupying the position of the triforium. The upper arcade, which takes the place of the clerestory, has shafts of triple form, with wide spreading bases and caps of Norman and transition design. On the latter rest the round boldly-moulded arches. The arches opposite the windows in the outer wall are slightly larger than the others. It will be observed that there is no main vaulting shaft carried up over the main piers, as is almost invariably the case, for the purpose of strengthening the wall. On the contrary, the triforium arcade is continuous, and no provision is made to support the side wall, except the single shafts of the running arcade, which have a very weak effect. In the usual arrangement, the triforium arches are separated by a substantial piece of wall, including a vaulting shaft, and the triforium arch, which is generally subdivided into several subordinate arches, is introduced between the vaulting shafts. That is a much more substantial form of construction, and also more satisfactory to the eye, than the plan adopted here of a simple continuous arcade." In the exterior of this portion of the choir the outside of the clerestory windows is visible, being simple round-headed openings, with flat buttresses between them. The remainder of the wall is plain, but, judging from the level of the triforium window, the vaulting of the aisle, which was very high and partly covered the windows, seems to have been added at a later date. The crossing is square; the piers are about nine feet square--that at the south-east angle standing detached in consequence of the opening into the south aisle, while those at the north-west and south-west angles are incorporated with the walls. The piers are designed as a series of shafts, set in square nooks (four on each of the complete sides), with a large semicircular shaft at each angle. The shafts are all built in courses with the piers, and have transition bases and caps. From the latter spring large pointed arches, with plain chamfered orders. The pointed arch indicates the transitional character of this part of the building, and was probably introduced in this position to give strength to sustain the tower. The three arms of the cross branching to the north, south, and west from the