On the west side, this part of the transept almost repeats what is to be observed on the east; but the parapet here is the same as that on the north end, and near the ground is one of the twelfth-century windows. The arch-mould of its rounded head is the same in detail as those in the priest-vicars' vestry and in the chamber above the present library. It seems to be an example of that later work of the twelfth century of which other specimens no doubt remained in the walls of the lady-chapel before Bishop Gilbert transformed it into its present state. Close to this window, and rising up just above the sill of the clerestory windows, is a narrow, flat buttress, which is probably of the same date as the window. Its upper half has an attached shaft on each angle, with moulded bases and carved capitals of the same period; but the weathering on its top appears to have been changed in the thirteenth century. Close by is the only part now remaining of the twelfth-century outer wall of the nave aisle. The original corbel course of the parapet remains, but not the upper part of the parapet. And it may be seen here that the small windows that lighted the triforium gallery had round arched heads in two orders, with a string-course at their sill. Below this string is a thirteenth-century pointed window, with a billet-moulded label cut in a twelfth-century manner of design. [Illustration: THE CATHEDRAL FROM THE NORTH-EAST. _Photochrom Co., Ltd., photo_.] The north side of the nave retains the seven twelfth-century clerestory windows, the one next to the transept having been rebuilt after the fall of the central tower and spire in 1861. There are no remains of later insertions, as on the south side. The parapet is later in design than those to the choir and lady-chapel; but it is of the same date as that on the south wall of the nave. In the five eastern bays it is of two tiers. The upper projects beyond the lower, and so widens the span between the north and south clerestory walls. It has been suggested that this was done in order to straighten the north wall, which in the twelfth century had been built so that it bent inwards towards the south. The weathered and channelled backs of five of the buttresses are the same date as those south of the nave; but the easternmost one has a flat raking back like those to the north and south of the choir and presbytery. The four western buttresses had pinnacles with spirelets--now destroyed. The western one was square, the other three octagonal. All these are earlier in date than the fifth one from the west, this last one being probably the same in date, as it is in detail, as those on the south side. The sixth one finishes plainly with a square top. It may once have had a pinnacle, but none now remains.