First, with the aid of strong levers of wood hardened by fire, the stones which obtruded above the level of the plateau were forced out and arranged on the perimeter described; then upon this layer, behind which was heaped coarse gravel mixed with earth, were placed trunks of trees, crosswise, four feet apart. The width of the base was twenty feet. The interval between the trunks was filled with stones, earth, and branches. Then another layer of stones mingled with earth, then three rows of trunks of trees, laid this time lengthwise, bound together with strong bands of green withy, always with gravel between. On this a third layer of stones, more trunks of trees across, overlapping the others, and a topping of gravel, of turf and soil, forming the rampart walk. Stakes were placed upright, five feet apart, and firmly driven three feet down into the rampart on the outer edge, serving to fix, by means of osier bands, wattled hurdles five feet six inches high, so as to form a continuous parapet pierced with loop-holes. The rampart rose to a height of five feet. The inclosure completed, the Druids marked out the area allotted to the eight tribes. To each of them was given a circular space of two hundred feet in diameter; the huts were disposed in two rings around the perimeter; in the middle was the paddock for the animals and the hut of the chief. [Illustration: FIG. 2.--THE OPPIDUM.] The general view of the camp is given in Fig. 2, with the rampart, the two entrances, the sunk approaches, defended on the other side by a mound raised with the earth excavated to form these approaches, and the eight circles allotted to the tribes; at A, the Némède and the dwelling of the Druids and Druidesses, surrounded by the sacred inclosure. Wells were sunk in each of the circles of the tribes, and in the inclosure of the Némède. [Illustration: FIG. 3.] Fig. 3 gives the section of the rampart with its terrace-walk, A, for the defenders, and, at intervals, the inclines, B, affording an easy means for ascending to the terrace-walk. The entrances were masked by a mound forming an advanced work, and leaving two ways out along the ramparts. Fig. 4 shows how these entrances were disposed. The two extremities of the rampart were strengthened by a wider embankment, H, affording space for a numerous assemblage of defenders. Here is shown the screen thrown up outside the cutting, and at K the sunken road with its mound, L. [Illustration: FIG. 4.] Fig. 5 represents the Némède, with its inclosure and the dwellings of the Druids. [Illustration: FIG. 5.] The camp finished--except the habitations of the tribes, whose site was only marked by circles of stones--a certain number of young men were put to live there, who replaced each other every day. Arriving there at sunset, they remained in the camp until the beginning of the next night. Those of the former inhabitants of the valley who still lived were forbidden to enter the camp on pain of death.