Other chapels, less distinguished, which have been added from time to time, line the nave both north and south, and all are excrescent to the original plan. Of the exterior, only the facade retains its primitive character. The side-walls, "entirely featureless," as has been well said, "reflect only the various periods of the chapels which have been added to the Cathedral," and the apse was re-built in 1671, in a heavy, uninteresting form. [Illustration: "THE INTERIOR HAS A SHALLOW, GRACEFULLY BALUSTRADED BALCONY."--AVIGNON.] These additions, superimposed ornamentations, and rebuildings, together with the very substantial substructure of the primitive Cathedral, form to-day a small church of unimpressive, conglomerate style, and except for its history, unnoteworthy. It is therefore a church whose interest is almost wholly of the past; and the traveller goes back in imagination, century after century, to the era of Papal residency, when the Cathedral was not only ecclesiastically important, but architecturally in its best and purest form. This church, which Clement V found on his removal to Avignon, and which may still be easily traced, was of the simple, primitive Provencal style. No dates of that period are sufficiently accurate to rely upon; but its interest lies not so much in chronology as in its portrayal of the general type. The interior is the usual little hall church of the XI century, with its aisle-less nave of five bays, and plain piers supporting a tunnelled roof, with double vault arches. Beyond the last bay, over the choir, is the Cathedral's octagonal dome, and from the rounded windows of its lantern comes much of the light of the interior, which is sombre and without other windows of importance.