On September 7, the encounter became closer and more severe, without any marked change of position, the 67th and 75th Divisions, on the right, carrying Ippecourt by assault (to lose it next day), the 6th Corps resisting obstinately on either side of Rembercourt, and, on the left, the 5th Corps meeting furious attacks around Vassincourt. In the evening, the 29th Division of Castelnau’s 15th Corps passed the Marne to Combles and Fains, two battalions of chasseurs reaching Couvonges and the neighbouring woods. On the morning of the 8th, Sarrail’s 5th Corps was supported and extended by the full strength of the 15th. One brigade of the latter was directed by Vassincourt toward Revigny, but could make no headway. Other brigades came into action near Louppy and Mognéville; nevertheless, Villotte and Louppy-le-Château were lost. News arriving that de Langle’s right had been driven back from Sermaize to Cheminon, and that Duke Albrecht’s forces were at the foot of the Trois-Fontaines plateau, d’Urbal was ordered to take his cavalry corps round, and to harry the east flank of Tchenk’s movement. No sooner had it reached the upper Saulx valley for this purpose than Sarrail hurried it back and away north-eastward to meet a yet extremer danger beyond the Meuse.
Below St. Mihiel, the river meanders beside a wall of steep hills, on the crests of which were situated a number of forts, dependencies of the Toul and Verdun systems, designed as observatories and points of arrest against an enemy march toward the principal crossings. The most important of these forts were Genicourt, Troyon, and the Roman Camp along the east, and Paroches on the west, banks. Troyon was an extensive square structure, sunk in a deep, wide moat, and garrisoned by about 450 men. Commanding the gap of Spada, it enjoyed, in its remote solitude, magnificent views over the plain of the Woevre as far as Metz, and the hills and valleys between St. Mihiel and Verdun. It has not been explained why the troops of Metz did not reach the Meuse earlier; probably their heavy artillery delayed them. On the morning of September 7, there was no sign of trouble on the Heights, and the commander of Troyon, Captain Xavier Heym, went out partridge shooting. At noon, forces of infantry and cavalry, with thirty cannon, were reported on the roads from Hattonchatel and Heudicourt. The bombardment began at 2 p.m.; and before another day had passed, 400 heavy shells, some of them from 12-inch mortars, had been thrown upon the fort, putting seven guns out of action, and demolishing large parts of the casemates and galleries. This news was a crown to Sarrail’s anxieties. He had no reserves left; the 3rd Army was wholly engaged. Its right might at any time be crushed, its left enveloped: now it was menaced in the rear. The dispatch thither of some tired cavalry was, of course, the merest bluff. Whatever might have been the fate of Verdun, the crossing of the Meuse at a higher point would have meant the withdrawal of Sarrail’s right, and the opening for the Crown Prince of the shorter route for reinforcements and supplies which he so much needed.