The gallery does not lead directly to the spring which existed in the time of the Gauls. The Roman miners, after having made their way straightforward for a length of six mètres, came upon a thick bed of blue marl of the lias: they turned to their left to avoid digging through it, and advanced four mètres farther, following the marl, which they left to the right. When they reached the end of the marls, a horizontal layer of hard rock, one mètre thick, obliged them to bring the gallery back to its former direction, and to raise it, in order to avoid this new obstacle without going out of the tufas, which, formed by the waters, would necessarily lead towards the spring. (_See Plate 32._) From this second turning, the gallery continued close to the line of separation of the marls and the tufas. It rose rapidly, until it reached the limit of the deposits of tufa. At this point blindage had again been necessary. It was there chiefly that the blocks of petrification presented a peculiar character: some lay thrown down in the gallery, pierced by sockets with a rectangular section, which show the dimensions and the way in which it had been worked; others, with a rounded base, are veritable uprights, still standing on the rock. Independently of the excavations made to find the Roman fosses and the subterranean gallery, others have been made on the slope of Loulié, in the soil which is near the spring. They have brought to light numerous fragments of Gaulish pottery and of amphoræ, and, which is a further confirmation of the identity of the Puy d’Issolu with Uxellodunum, remains of arms similar in all respects to those found in the fosses of Alesia.[555] Under the earthfalls which during nineteen centuries have taken place on the slope of Loulié, all the traces of the fire described in the “Commentaries” have been also found. The site of the terrace and the covered galleries which were fired were also traced on the ground. _Plate 32_ represents the slope which was the scene of the struggle: the terrace, the tower, and the covered galleries are represented on it, as well as the subterranean gallery, according to a very exact survey made on the spot. [Sidenote: Complete Submission of Gaul.] VIII. Whilst these events were taking place on the banks of the Dordogne, Labienus, in a cavalry engagement, had gained a decisive advantage over a part of the Treviri and Germans, had taken prisoner their chief, and thus subjected that people, who were always ready to support any insurrection against the Romans. The Æduan Surus fell also into his hands: he was a chief distinguished for his courage and his birth, and the only one of that nation who had not yet laid down his arms.