§ XIV. The shaft, however, rapidly rallies, and brings up its own peculiar decorations to its aid; and the intermediate archivolts receive running or panelled ornaments, also, until we reach the exquisitely rich conditions of our own Norman archivolts, and of the parallel Lombardic designs, such as the entrance of the Duomo, and of San Fermo, at Verona. This change, however, occupies little time, and takes place principally in doorways, owing to the greater thickness of wall, and depth of archivolt; so that we find the rich shafted succession of ornament, in the doorway and window aperture, associated with the earliest and rudest double archivolt, in the nave arches, at St. Michele of Pavia. The nave arches, therefore, are most usually treated by the chamfer, and the voussoirs are there defeated much sooner than by the shafted arrangements, which they resist, as we saw, in the south by color; and even in the north, though forced out of their own shape, they take that of birds' or monsters' heads, which for some time peck and pinch the rolls of the archivolt to their hearts' content; while the Norman zigzag ornament allies itself with them, each zigzag often restraining itself amicably between the joints of each voussoir in the ruder work, and even in the highly finished arches, distinctly presenting a concentric or sunlike arrangement of lines; so much so, as to prompt the conjecture, above stated, Chap. XX. § XXVI., that all such ornaments were intended to be typical of light issuing from the orb of the arch. I doubt the intention, but acknowledge the resemblance; which perhaps goes far to account for the never-failing delightfulness of this zigzag decoration. The diminution of the zigzag, as it gradually shares the defeat of the voussoir, and is at last overwhelmed by the complicated, railroad-like fluency of the later Gothic mouldings, is to me one of the saddest sights in the drama of architecture.