in addition two lesser blind arches, one in each of the wall spaces on either side. The triforium and lower arcade differ only in decorative treatment from those of the nave and choir (Fig. 87).
Externally there is no pier buttress whatever, not even a pilaster strip, either above or below the head of the flying buttress. In place of it is a broad space of wall, with two tall niches in its surface, between which the flying buttress is brought to bear (Fig. 88).
88.
The nave of Lichfield, which must be nearly contemporaneous with the Presbytery of Lincoln, differs in many points from the buildings already noticed, though in structural character it is not essentially different. Its vaults exhibit the peculiarity of having no transverse ribs; but they have tiercerons, longitudinal and cross liernes, and a surface rib in each lateral cell. The springing of the longitudinal arch
