Luckily these formidable defensive positions were approached from the west, astride the ridges. Starting from the forest of Retz, the French crossed the Savieres with a rush, and in a single bound reached Noroy-sur-Ourcq and Villers-Helon, which lie along one of the ridges, surrounded by orchards. On July 19 they had advanced three kilometres to the east; the strong line of the Ourcq was outflanked. On the 20th they were at Parcy-Tigny and Rozet-St.-Albain, pushing forward over the broken ground planted with sugar-beets and cereals, enlivened in spots by small clumps of trees perched on the sandstone hillocks. Thus they drew near to the heart of the position--the ridges of Plessier and of Hartennes. There the resistance was much more violent; but after three days of hard fighting, the French entered Plessier and approached the village of Oulchy-la-Ville, surrounded by picturesque heaps of sandstone blocks mingled with pines and birches. On the 25th, in the evening, they were in occupation of Oulchy-le-Chateau, which lies in a charming vale running down to the Ourcq. The line of the Ourcq, as to that portion where the river, flowing between high cliffs, constitutes a real obstacle, was in the Allies' hands. [Sidenote: Fere-en-Tardenois and Sergy.] It remained to complete the victory by the conquest of the eastern sector of the hills; and this again was no easy task. The French and Americans had now to approach that strong defensive position from the south. On the 28th they entered Fere-en-Tardenois; the Americans crossed the Ourcq, taking Sergy, which changed hands nine times. On July 31, after more titanic battles, they wrested Seringes from the foe. On August 1 there was a general advance all along the line, and the Allies carried the whole line of hilltops, from Plessier-Huleu to Meuniere wood. [Sidenote: Heroes of the second battle of the Marne.]