The valley of the Scarpe is held in on the south by low hills, and on the north by a low plateau, which descends in long ridges to the valley of the Lys and the plains about Lens. The greatest altitude in this section is the ridge known as Notre-Dame de Lorette, running east and west, and containing numerous ravines. To the south of it, in a little valley, is the town of Albain St. Nazaire. Carency is opposite on the next ridge. Next is the Bois de Berthonval in the middle of a wide depression. Beyond, the land ascends to Mont St. Eloi. The valley of the Lys is to the north of the Lorette ridge. To the east the land descends to the long, narrow valley in which is the highway between Arras and Bethune. La Targette and Souchez are along the way. Again the land rolls upward to the hills of Vimy with the Lens-Arras highway beyond them. The Teutons held a salient in this region at the beginning of May, 1915. The line which bounded this salient ran east of Loos over the Bethune-Lens road, east of Aix-Noulette, and appeared on the Lorette plateau considerably to the west of its tallest spur, where was situated the Chapel of Our Lady; running out to the prow of the salient, it took in Albain; and then proceeded to Carency; bending closely, it ran east of the Bois de Berthonval, taking in La Targette and the Arras-Bethune highway. That part of the German line was called by the French the "White Works," on account of the chalk with which the breastworks were constructed. To the southeast of it was a section known as the Labyrinth. Ecurie was inside the line which finally ran back east of Arras. The salient was constructed for the guarding of Lens, which was considered the entrance to the upper valley of the Scheldt and the lowlands in the direction of Douai and Valenciennes. Of more importance than Lens itself was the railroad back of this front, the capture of which would naturally be a source of great danger to the Germans.