Watts) and 21st Division (Major-General David Campbell) of XV Corps, faced no man's land which was wide south of Bazentin le Grand Wood, Bazentin le Petit Wood, village and the cemetery east. The advance would be uphill except beyond Mametz Wood, where the ground was flat. The 18th (Eastern) Division (Major-General Ivor Maxse) was to set up a defensive flank on the east face of Trônes Wood, between the 9th (Scottish) Division and the French 153rd Division, which would support the 18th (Eastern) Division with artillery if necessary. On the left flank, the 1st Division was to form another defensive flank in the Pearl Alley communication trench and capture Contalmaison Villa, to link with the 21st Division at Bazentin le Petit Wood. (At on 13 July, the 1st Division attacked with the 1st Black Watch and captured Lower Wood, north of the top left of Mametz Wood and Contalmaison Villa at on 14 July. The 18th (Eastern) Division at Trônes Wood diverted German attention on the east flank and it had been assumed that the French XX Corps would participate in the attack south of Guillemont. The failure of French attacks from 7 to 8 July, led General Ferdinand Foch, () to order Fayolle to wait on the British attack () and only artillery support was made available. Three cavalry divisions were to be ready by to exploit success, the 2nd Indian Cavalry Division (Major-General G. A. Cookson) by capturing High Wood north-west of Longueval, the 1st Cavalry Division (Major-General Cecil Bingham) Leuze Wood, beyond Guillemont and the 3rd Cavalry Division (Major-GeneralJohn Vaughan) to capture Martinpuich. The 2nd Indian Cavalry Division was placed under the command of XIII Corps and the other two divisions remained under the Fourth Army HQ, for Rawlinson to decide when they were to attack, according to reports from the corps and from air reconnaissance. Offensive preparations A preliminary bombardment began on 11 July, with counter-battery fire and shelling of the attack front. The fire of the three corps continued at night on villages and woods further back and approach routes from them to the front line, especially Waterlot Farm, Flers, High Wood, Martinpuich, Le Sars and Bapaume. A shortage of heavy artillery ammunition and transport difficulties over wet and cut up ground, led to a ration of and shells per day, for two days. The field artillery was moved forward to the south side of