The upper portion of the west front above the two large windows is undoubtedly of considerably later date. The design of the west front, which contains above the doorpiece two large windows, with pointed niches and small circles inserted between the arch-heads, is probably original, but the upper portion and gable, including the large traceried window, are doubtless part of the restoration of the fifteenth century. The tracery of the two central windows is peculiar, and may possibly be of the fourteenth century, but that of the large upper window is later, probably of the same period as the restoration of the interior of the nave. The tracery of the large upper window is a specimen of the late kind of design employed in Scotland in the fifteenth century. The change of style caused by the restoration of the fifteenth century is well marked in the interior at the west end of the nave. The first or western bay of the main arcade is original (Figs. 961 and 962), including the first arches (one on each side), the first pillars and the arches between them, and the aisle responds. These pillars and arches are of large dimensions and first pointed section (Fig. 963), and appear to have been designed to carry western towers, but a part of their thickness has been cut off next the choir. A portion of the triforium wall, a piece of the string course over the main arcade, and the corbelled vaulting shaft in the angle as high as the top of the triforium, are also parts of the original structure. The later work has been joined to the above old parts in a very awkward manner. The wall over the large pillars has been thinned on the side next the nave, and the different width and sections of the mouldings have not been properly adjusted, the result being that part of the older moulding is left at the springing of the second arch on the north side, and the mouldings of the later section are butted against it (see Fig. 961). [Illustration: FIG. 959.--Paisley Abbey. West Part of South Side of Nave.] [Illustration: FIG. 960.--Paisley Abbey. West End of Nave: Exterior.] [Illustration: FIG. 961.--Paisley Abbey. West End of Nave and Part of North Side.] [Illustration: FIG. 962.--Paisley Abbey. West End of Nave and Part of South Side.] There are signs of further alteration above the west arch. A clumsy new string course is introduced, which slightly changes its section after passing along half a bay. A second vaulting shaft is carried up in the [Illustration: FIG. 963.--Paisley Abbey. West Piers and Respond in Nave.] angle beside the original one as high as the triforium arch and there stops. The first triforium arch, which is pointed (all the others being round), abuts against the wall in an awkward manner (see Fig. 961), the original design being changed.