The war on the Western Front was a constant battle with the geological conditions. In the Ypres Salient, the impervious Ypres Clay meant that drainage was not easy, with trenches often wet and shallow, but the clay provided perfect conditions for military tunnelling and dugout construction. For the Germans, higher ground meant easier observation over the British, but the geological conditions conspired against them. As discussed in the book 'Beneath Flanders Fields' (Peter Barton, Peter Doyle, Johan Vandewalle), the Germans were to lose the war underground.