Another feature which shows that the York canons had started their work without considering whether they would be able to finish it is the omission of a stone vault, which was plainly contemplated at the outset; the pinnacles built for the purpose of weighting the buttresses against the thrusts of a stone vault still existing on the south side. When the north side was built, the canons had abandoned hope of vaulting the nave in stone, and so did not put up big pinnacles. It is well to remember, however, that the exterior of the nave was designed originally to have flying-buttresses and big pinnacles on both sides. In the end, as in Selby choir, a sham vault of wood was put up. One cannot help regretting these shams. It would have been Gothic to recognise honestly that the ceiling was wood, and to design it in wood and not in lithic fashion. Then we might have seen an English Gothic cathedral with such a hammer-beam roof as that of Westminster Hall: very magnificent it would have been. Side by side with the nave went up the chapter-house. It belongs to the middle of the Geometrical period, _c._ 1300; later in character than its sister at Southwell, and but little earlier than the chapter-house of Wells. Externally, it is provided with buttresses and pinnacles and flying-buttresses and flying bridges to resist the thrusts of a stone vault. Yet no stone vault is there, but another sham vault of wood. The detail of the chapter-house, inside and outside, is of exquisite beauty. At first the chapter-house was a detached building, but a vestibule was soon added. Parapet-mouldings of the chapter-house may now be seen inside the vestibule.