Below the cross-wall, with its massive double gate, lay that part of the fortress which contained the cathedral and public buildings, and formed the inhabited portion of the original fortified town. Like the citadel, it was protected on two sides by the ravines, lined on their inner edge by a lofty wall seven feet in thickness, with towers at intervals. A second cross-wall, extending from ravine to ravine, was its bulwark on the side of the sea, and constituted the outer rampart of the enclosure as it existed in the ancient form. This outer rampart followed the edge of a natural declivity in the surface of the shelving ground, and presented a bold front to the lower levels lying between it and the shore. The third and lowest stage of the fortified enclosure filled the space that yet remained between this outer wall of the city and the immediate margin of the sea. The ravines open outwards as they approach the seaboard, and the figure widens which they bound; but on the other hand, the sides of these natural barriers flatten and take the surface of the adjoining ground. Thus the plan of the lower fortress did not display the same subservience to the natural features of the site, and was protracted on the west beyond the outer margin of the western ravine. Indeed, the area enclosed by this later work of the fourteenth century was considerably greater than that of the ancient burgh; and in proportion as it was deficient in natural defences, so it was stronger in those of art. A wall six feet and a half in thickness, with towers at irregular intervals, surrounded the new work; and, except on the side of the sea, this rampart was flanked by a second and lower wall with a moat on its outer side. But, although the lower fortress formed a third and separate unity, overstepping the natural limits of the site, it was connected in the closest manner with the upper enclosure, and with the walls flanking the ravines. On the east the new ramparts joined the old wall, and continued its direction in a straight line to the shore, at which point they turned at right angles, along the shore. Thus the old cross-wall was completely covered by the new fortifications, and the principal gate of the old city, leading through that wall and facing the sea, instead of standing at the outer extremity of the fortress, now became situated in about the middle of the fortified plan. The new wall along the sea was protracted further westwards than the western extremity of the old cross-wall; it was drawn across the mouth of the western ravine, and far overlapped the parallel line of the old wall. Some little distance west of the depression it again changed direction, and stretched up towards the south, until it reached a point opposite to the bridge which leads out from the middle fortress, and over 100 paces from the edge of the ravine. From this point, which was emphasised by a rectangular tower of extraordinary size, the line of wall was taken at right angles,