the Albert–Bapaume road were about wide. German artillery was organised in a series of (barrage sectors). A telephone system was built with lines buried deep, for behind the front line, to connect the front line to the artillery. The Somme defences had two inherent weaknesses which the rebuilding had not remedied: The first was that the front trenches were on a forward slope, lined by white chalk from the subsoil and easily seen by ground observers. The second was that the defences were crowded towards the front trench, with a regiment having two battalions near the front-trench system and the reserve battalion divided between the and the second line, all within of the front line, accommodated in the new deep dugouts. Prelude German preparations The headwaters of the Ancre river flow west to Hamel through the Ancre valley, past Miraumont, Grandcourt, Beaucourt and St. Pierre Divion. On the north bank, pointing south-east, lie the Auchonvillers spur, with a lower area known as Hawthorn Ridge, Beaucourt spur descending from Colincamps and Grandcourt spur crowned with the village of Serre. Shallow valleys link the spurs, the village of Beaumont-Hamel lies in the valley between Auchonvillers and Beaucourt spurs. A branch in the valley known as Y Ravine lies on the side of Hawthorn Ridge. In 1916, the front of VIII Corps lay opposite the line from Beaucourt to Serre, facing the series of ridges and valleys, beyond the German positions to the east. The German front line ran along the eastern slope of Auchonvillers spur, round the west end of Y Ravine to Hawthorn Ridge, across the valley of Beaumont-Hamel to the part of Beaucourt spur known as Redan Ridge, to the top of the Beaucourt valley to Serre. An intermediate line known to the British as Munich Trench began at Beaucourt Redoubt and ran north to Serre. The second position ran from Grandcourt to Puisieux and the third position was further back. No man's land was about wide from the Ancre northwards and narrowed to about beyond the redoubt on Hawthorn Ridge. The ground was flat and unobstructed, except for a sunken road from the Auchonvillers–Beaumont-Hamel road and a low bank near the German front trench. The German front had several shallow salients, flanks, a bastion at the west end of Y Ravine and cover in the valleys to the east. Beaumont-Hamel commanded the valley, which the VIII Corps divisions were