The square tower over the crossing is seen (see Fig. 563) to rise externally only a short way above the apex of the roofs of the choir and transept. Like the choir, it has been intended to be vaulted, the springing stones being still visible (see Fig. 558); but the supports were either found to be too light, or were so damaged by the fire that, as above mentioned, the piers and arches had to be strengthened with supporting walls brought up from the foundation. The upper part of the tower appears to have originally been of the date of the transept, and to have been restored, like the rest of the edifice, at a later period. This is evident from the shape of the window openings, which are of first pointed work, and also from the corbels of the parapet, some of which are original and of early form, while others, which have been restored, are of the late form common in the churches and castles of the fifteenth and sixteenth centuries. The large trefoil apertures have suffered from the fire, and have been built up. To the north of the choir is a small vaulted structure about 16 feet square, called the Dunbar Vestry (see Plan). It is evidently of late date, and its style supports the tradition that it was erected by Prior Dunbar shortly before the Reformation. It is vaulted, and bears the arms of Dunbar on one of the bosses.[59] [Illustration: FIG. 564.--Pluscarden Priory. Sacrament House in Choir.] Apparently of the same date is the sacrament house (Fig. 564) inserted in the north wall of the choir, and a door between the choir and vestry, which has the three-sided arch common at the period. On the north side of the vestry are some remains of a door and wheel stair, the latter of which appears to have led to the roof. The position of the vestry is very awkward, being placed within two feet of the transept aisle, the windows of which are thus almost obscured by it. The part of the church lying immediately to the south of the transept is called the sacristy, or the lady chapel. It is vaulted, and from the form of the mouldings, caps, window, &c., is evidently of the same date as the transept. The vaulting at the west end has been partly rebuilt, and a fireproof closet formed in the angle, no doubt for the purpose of containing valuables used in the service. At the east end a ruined opening into the transept seems to have been a squint to allow the service at the altar to be seen from the transept. Traces of colour are still observable here, but in Cordiner’s time many emblematic paintings were visible. To the south of the sacristy is the chapter house, and beyond it the slype. These have been restored within recent times, and the east windows renewed in the same pointed segmental form as the old ones. The doors and windows to the west have also been partly renewed.