The main arcade of the nave (Fig. 492) has consisted of eight bays. Those of the south side still stand, but on the north side only two shattered piers survive. The piers are of the simplest form of clustered columns, each containing a three-quarter round shaft on the four cardinal angles, with two nook shafts between. The shafts are all crowned with richly foliaged caps, having rounded abaci. The arch mouldings consist of rounds and hollows, all deeply marked. From the cap of the main pier springs a triple vaulting shaft, which runs up through the triforium and receives the springing of the vaulting ribs on plain bell-caps some feet below the string course under the clerestory. The triforium is divided into two arches in each bay by a single central shaft, springing from a corbel over the apex of each arch of the main arcade, and running up to the string course beneath the clerestory. This would appear to indicate that the vaulting was sex-partite, which view is confirmed by the direction in which the surviving portions of the groins point. [Illustration: FIG. 492.--Holyrood Abbey. Interior of West End.] [Illustration: FIG. 493.--Holyrood Abbey. View from South-East.] Each arch of the triforium (see Fig. 492) is acutely pointed, and contains two smaller acutely pointed arches within it, each of which has an inner trefoiled arch. These arches all spring from single round shafts, with plain round caps arranged to receive them. The tympanum of the large arch is pierced with a quatrefoil or trefoil. All the mouldings are of a bold first pointed character. The triforium, no doubt, contained the usual passage in the thickness of the wall, which would tend to weaken the structure. To counteract that tendency, as may be seen from the south (Fig. 493), strong saving arches have been introduced to carry the chief pressure across from main pier to main pier. A similar strengthening arch exists in the outer wall of the triforium gallery at Amiens Cathedral. The west end of the edifice has contained the finest work of the building. The west wall, with its splendid doorway between the two western towers (Fig. 494), must have presented as bold and ornate a piece of architecture as was to be found in Scotland. [Illustration: FIG. 494.--Holyrood Abbey. North-West Tower and West End.] The west front is now greatly shorn of its glory, but the portions which remain only tend to increase the regret for what is gone. As already mentioned, the south-west tower was removed to allow of the palace being erected, and even the western doorway is encroached on by [Illustration: FIG. 495.--Holyrood Abbey. West Doorway.]