Mr. Muir may well have been deceived with regard to the existing south aisle, for it is a structure of unusual size and splendour, and, in its present solitary condition, presents rather the appearance of a complete church, with distinct choir and nave, than that of a nave aisle. It is composed of two parts (Fig. 807), an eastern portion, which measures 41 feet 6 inches in length by 21 feet broad, and a western portion, 56 feet 6 inches long by 14 feet 9 inches broad, with a bell turret projecting at the angle where the two parts meet. [Illustration: FIG. 807.--Fortrose Cathedral. Plan.] Both of the divisions are elegantly vaulted in the English style, with ridge ribs and tiercerons or intermediate ribs. On the north side is a range of clustered pillars and arches, forming five bays, which separated the aisle from the nave. Some of the arch openings are enriched with canopied monuments. The east end (Fig. 808) contained a large traceried window of five lights, and some fragments of the tracery still cling to the arch. The window is rather short for its width, being kept high, so as to admit of an altar and reredos. The south wall has also been pierced with traceried windows, now, unfortunately, mutilated. The other division towards the west end contains a doorway, formerly sheltered by a large porch, now demolished. The exterior (Fig. 809) presents, at the east and west ends, the appearance of complete gables, with a span roof, not a lean-to roof, as is usual over aisles. The buttresses are of good form, and the enriched cornice still survives. The parapet is gone, but at the west end a wide stone gutter, or alure, supported on corbels and roofed in, still remains. The windows of the western portion are less elaborate than those of the eastern portion. [Illustration: FIG. 808.--Fortrose Cathedral. East End of South Aisle.] [Illustration: FIG. 809.--Fortrose Cathedral. View from South-East.] In the angle between the two divisions of the aisle a staircase and bell turret are erected. Rising from a square base the walls are changed by a set-off on each angle into an octagon; a balcony is carried round the turret, and the top is finished with a modern pointed roof. The whole of the architecture of the aisle is of unusually good design, and the building is altogether quite unique and full of beauty and interest.