§ IX. So far, then, of the Southern archivolt: In Fig. LXIX., above, it will be remembered that _c_ represents the simplest form of the Northern. In the farther development of this, which we have next to consider, the voussoirs, in consequence of their own negligence or over-confidence, sustain a total and irrecoverable defeat. That archivolt is in its earliest conditions perfectly pure and undecorated,--the simplest and rudest of Gothic forms. Necessarily, when it falls on the pier, and meets that of the opposite arch, the entire section of masonry is in the shape of a cross, and is carried by the crosslet shaft, which we above stated to be distinctive of Northern design. I am more at a loss to account for the sudden and fixed development of this type of archivolt than for any other architectural transition with which I am acquainted. But there it is, pure and firmly established, as early as the building of St. Michele of Pavia; and we have thenceforward only to observe what comes of it. § X. We find it first, as I said, perfectly barren; cornice and architrave altogether ignored, the existence of such things practically denied, and a plain, deep-cut recess with a single mighty shadow occupying their place. The voussoirs, thinking their great adversary utterly defeated, are at no trouble to show themselves; visible enough in both the upper and under archivolts, they are content to wait the time when, as might have been hoped, they should receive a new decoration peculiar to themselves. § XI. In this state of paralysis, or expectation, their flank is turned by an insidious chamfer. The edges of the two great blank archivolts are felt to be painfully conspicuous; all the four are at once beaded or chamfered, as at _b_, Fig. LXX.; a rich group of deep lines, running concentrically with the arch, is the result on the instant, and the fate of the voussoirs is sealed. They surrender at once without a struggle, and unconditionally; the chamfers deepen and multiply themselves, cover the soffit, ally themselves with other forms resulting from grouped shafts or traceries, and settle into the inextricable richness of the fully developed Gothic jamb and arch; farther complicated in the end by the addition of niches to their recesses, as above described.