Not far from Saint-Thibéry the Via passed over the Hérault at that point where, in the seventeenth century (about the year 1678), the river was split into halves by a great flood, which formed the Île des Bénédictins; the Roman bridge is on the western branch of this divided river. Four arches exist, but originally there were nine, with spans ranging from ten to twelve metres. The piers have cutwaters both upstream and downstream, with circular bays nearly two metres high for the relief of spate water. The facing stones are long, and the filling is local volcanic rubble. This bridge was wrecked by a flood before the year 1536. The Via Domitiana was carried over the Orb, and then, following the ancient road of Colombiers, it crossed the Capestang by a Roman viaduct called the Pons Selmis or Pontserme, which in 1430 was repaired with 500 quarters of stone 2½ pans long by 1¼ pans thick and wide. It was a tremendous viaduct, its length being 1500 metres; the width did not exceed three metres. In the sixteenth century it fell in for want of repair. At the present time only an isolated arch remains, with fragments of two others. In a document of A.D. 782 this bridge is called Pons Septimus. Another Roman road left Nîmes in the direction of Larzac, and near Lodève apparently it joined the ancient road from Saint-Thibéry to Millau; at Sommières it crossed the Vidourle by a magnificent Roman bridge which had no fewer than seventeen arches. To-day only eight arches are visible, the others having been buried under a great accumulation of soil on both banks.[69] Yet the Pont de Sommières, though deprived of nine arches, has a high place among the Roman monuments. I have now to mention a Roman byway that branched out from the main road on the right bank of the Vidourle, at a little distance from Sommières; it ran toward Substantion, passing by Castries and joining the Via Domitiana near Vendargues. At Boisseron it crossed the river Bénovie, a small tributary of the Vidourle, by a bridge which to-day is extant, though disfigured by modern work. It has a shelving parapet and road, but we cannot describe it as a gabled bridge (p. 27). There are five arches of unequal size, the piers on the upstream side have cutwaters, and rectangular bays above the cutwaters ease the pressure of floods. Frank Brangwyn has drawn for us the wreck of a Roman bridge over the Loire, at Brives-Charensac, in the neighbourhood of Puy; and the big arch, which springs from water-level, is particularly interesting because it has a double ring of voussoirs. The smaller arch belongs to the Middle Ages, for it has a pointed shape. [Illustration: RUINS OF A ROMAN BRIDGE OVER THE LOIRE AT BRIVES-CHARENSAC, FRANCE]