The transition of style is to be observed on almost every side. Not, indeed, so much in the plain round pillars with capitals in imitation of the Roman composite, and with square abaci, as the eye accustomed only to English work might assume, for these in France were retained much later than in England, even throughout the period of Flamboyant. But in almost every direction you can see the tentative mason at work, leaving the old heavy style with its horizontal lines behind him, and making new experiments, discarding or developing fresh ideas which tended to the achievement of lightness and spring, but as yet hardly daring to believe to the full in the capacity of stone. Here, for instance, in the nave, the blind triforium has not broken yet into one continuous window, as it was soon to do in the Church of S. Père, of S. Ouen at Rouen, and at Amiens; nor have the heavy masses of stone been resolved into a network of delicate tracery, leaving not a span uncovered by its gossamer thread. The desire for lightness, again, which was in time to lead to the adoption of bar tracery is, in the case of the windows, evident, but not fully attained. Combined, however, with the rare opportunities offered to the architect by the excellent quality of the stone of Berchères, it has led him to invent a very simple and handsome type of window, which consists of two lancet lights under one arch, with a foliated circle in the head, the plate tracery of which is peculiarly heavy, and is cut through the solid stone. Between these circular openings, which fill a whole bay between the flying buttresses, and the heads of the lower lights, there is, as at Soissons, Bourges, Reims and so forth, a considerable interval of masonry. The foliated circles themselves are surrounded by a number of small trefoil or quatrefoil openings, not formed of bars, but likewise pierced through the solid stone.
[Illustration: FLYING BUTTRESSES OF THE NAVE.]
The buttresses of the nave, again, are amazingly heavy and massive, as if the workmen were still afraid to trust them to support the thrust of the vaulting of the roof at so great a height. This is borne by flying buttresses of enormous solidity, composed of an upper and a lower section, which are strengthened in turn by an arcade. The arcading is remarkable for its rugged grace, its masculine beauty. Its round-headed arches, which are supported by short, thick shafts, that remind one of the spokes of the wheel window, are composed of two large blocks of hewn stone.