Plate VII., Fig. 4, is a common type of window; an extension of the simple two-light window (Plate V., Fig. 9), frequently enriched with cusps and ball-flower (Plate VI., Fig. 3) in the hollows of the mullions. In Plate VII., Fig. 10, the buttresses are decorated with niches for statuary. A _flying-buttress_ is shown (F.B.), carrying the thrust of the stone-vaulted roof of the nave over the external roof of the aisle into the main buttress, whose weight and consequent stability are increased by the heavy _pinnacle_. The smaller buttress (C.) resists the thrust of the window arches. Norwich Cathedral displays an interesting array of flying-buttresses. Plate VI., Fig. 6, shows a tower and spire at the crossing of nave and transepts. The base of the spire and its _broaches_ (Plate V., Fig. 7) are concealed by a _parapet wall_, with battlements protecting a footway round the spire, which could be used as a place of observation. Mouldings in the Geometrical period attained the greatest refinement. Many can be favourably compared with those of the best Greek periods. Arches continued to be built in square orders (Plate III., Figs. 6 and 8), and consisted of round mouldings, generally separated by deep hollows and fillets (Plate VII., Fig. 7). In mouldings of the Curvilinear period (Plate VII., Fig. 8) the _ogee_ superseded the round, and the hollows were shallower. Towards the end of the period the square _orders_ ceased, and the planes of the _orders_ were at about 45° with the vertical (Plate VII., Fig. 9; compare with Plate VIII., Fig. 12). The _wave-moulding_ (Plate VII., Fig. 9) and the _scroll-moulding_ (Plate VII., Figs. 9, 12, and 13), supposed to resemble a parchment scroll, are conspicuous in the Curvilinear. The general character of the ornament is indicated on Plate VII., in most of which the _ogee_ line is apparent. The _ball-flower_ (Plate VI., Fig. 3) is a distinctive feature of the Decorated period superseding the tooth ornament of the Lancet (Plate V., Fig. 12). It was applied to hollow mouldings of arches and tracery of windows, vaulting, and spires. Capitals were moulded as in the section (Plate VII., Fig. 13), or carved, as Plate VI., Fig. 4, generally in imitation of natural foliage, varying from a bold conventionalism (Plate VI., Fig. 5) to a close imitation of nature, as Plate VI., Fig. 1 (a.a.). Animal forms and small human figures were occasionally introduced. Figure sculpture reached its highest degree of excellence in this period. Construction was further advanced, but in design the climax had been attained in the Geometrical period, and a very gradual decline set in, as shown in excessive ornamentation and literal imitation of natural forms in stonework, which is unsuitable for such delicate treatment on account of its fragility. The increasing wealth of the nation during this period is indicated by the grandeur of the buildings and the redundancy of ornament. PLATE VIII PERPENDICULAR, 1377-1547