This ornament extends along the six eastmost bays of the nave, the two westmost bays having a plain parapet on the same level. On the south side of the nave the aisle wall has been raised with red ashlar (like the choir south wall), and an ordinary parapet placed above it. The buttresses in the west part of the north side of the nave are of a late pattern, with two set-offs, and those on the south side of the nave have been repaired and altered. In the south side of the nave a new exterior doorway (see Fig. 238) has been substituted for the old Norman doorway, the shafts and arch of the latter remaining in the interior. The new doorway is said to have been inserted by Bishop Reid in the sixteenth century. This is the same Bishop whom we meet with as Prior of Beauly and Abbot of Kinloss (_q.v._) The doorway has the late form of a three-sided arch, and the mouldings are those common at the period (sixteenth century). In the centre of the lintel is the shield for a coat of arms, now obliterated, but a mitre is still traceable. A benitier adjoins the doorway, and there seems to have been a wooden porch or awning over it. The tower over the crossing (see Fig. 230) has been considerably operated upon in modern times. The old wooden spire was destroyed by lightning in 1671, and the tower consequently required repairs. The parapet and pinnacles are modern, as also the pointed and slated roof; but the lower part seems to be of considerable age (see Section, Fig. 227). The part within the roof of the church is apparently of transition date, and the upper part, with the large pointed windows, is probably of fifteenth century work. An unusually wide wheel stair leads from the north-west and south-west angles of the transept to the upper parts of the edifice. These stairs are connected with passages which circulate all round the clerestory and triforium in the thickness of the walls (Fig. 247), and give access to every part of the building. They also pass round the tower at each story, and are connected with small wheel stairs in the angles, by one of which access is obtained to the roof. There would appear to have been, at one time, numerous fine monuments in the cathedral, but they have all disappeared. An arched recess, with a gablet over it, in the south nave aisle (see Fig. 237) is now empty, but is supposed, by Sir H. Dryden, to have been erected for some member of the family of the Strathernes, Earls of Orkney.