of the ditch, of a line of branches having their tops pointing outwards, the better to form an obstacle.[1]

In front of the east gate—the Porta Praetoria of the fort—the roadway passed out on solid ground, but it did not, at least when first constructed, follow a straight line. The inner and middle ditches stopped on either side, leaving a space of about thirty-eight feet between the ends, but the outer ditch on the south side was prolonged so as to cover the gateway, thus deflecting the road to the north, while in its turn the outer ditch coming from the north with its line somewhat bent outward, again altered the course of the road to the south. The space for the track passing between these outer ditches was narrowed down to about twelve feet. On the south side the three lines of ditches were looped together, but this had no parallel on the north side; while running diagonally across the road from the end of the inner ditch on the north to that of the middle ditch on the south, was a narrow foundation trench thirteen inches wide, and carried down to a depth of one foot nine inches in the subsoil, which appeared to have been intended for a palisade or some such wooden barrier. In its complexity the plan recalls that of the east gate at Ardoch, or the earlier phase of the north gate at Lyne. In front of the west gate of the fort and the earlier gates on the north and south, an arm of the inner ditch had originally been carried across the front of the gate, thus forming a barrier closely analogous to the titulus, an obstacle whose presence opposite the gates of the great camp further to the east has already been alluded to. According to Hyginus,[2] the titulus was, however, an independent ditch of a length corresponding to the breadth of the gateway, sixty feet in front of which it was to he placed. A typical example from Scotland is the one which guarded the south gate at Bar Hill. In the cases under discussion the obstacle was not a true titulus. Although it covered the entrance, much as a titulus did, it allowed only a single passage on the left of the exit. Its outline was, in fact, that of an everted clavicula.

The portion of the inner ditch extending in front of the west gate was almost entirely cleared out. It proved to be seventy feet in length, seventeen feet wide opposite the gate, and sixteen feet nine inches deep

1 Ritterling, 'Toranlagen römischer Kastelle,' Fig. 10.

2 Liber de Mun. Castr. edn. Domaszewski, § 49. Regressis pedibus exterius sexaginta per latitudinem portarum similiter fossa fiet, quod propter brevitatem titulum cognominatum est.