Pierre at Bourges, S. Martin at Étampes, Chartres cathedral, the destroyed church of S. Martin at Tours, and finally what is, I think, almost the best complete Gothic plan, that of Rouen cathedral. In every one of these we see the surrounding aisle lighted by windows between the chapels, and the chapels are distinct and well-separated on the exterior, precisely as in these older churches in Auvergne. These buildings, therefore, have great value, not only as illustrating a chapter of the history of our art, but because the chapter which they do illustrate is just one of the most interesting I can conceive; being that which explains how and by what steps Gothic architecture, of which, as our national style, we are so justly proud, was developed from the noble architecture of the old Romans and Greeks, an architecture to which we owe, among other things, this great debt of gratitude, that it naturally led up to, and rendered possible, a Westminster, a Chartres, an Amiens, and all the other glories of our Christian architecture. You will have gathered that there are many similar features in the churches of the two provinces which I have been describing. They are shortly these: vaults and quasi-domes alike, and carried on the same kind of squinches or pendentives; the decoration with mosaics and its detail; the design and treatment of doors, either sculptured or inlaid; the form of trefoil cusping of arches, character of mouldings, sculpture, and decoration with painting, all of these are the same throughout both districts. The only marked difference, and it is important, is in the ground-plan, the cathedral of Le Puy having no chevet, but an east end derived from Romanesque rather than Byzantine precedents; and the other churches in its neighbourhood are generally similar in their plan.