I have been asked to explain the circumstances under which certain flint implements of the Le Moustier period were found near the trenches at Coigneux. And this with special reference to geological strata. Between the 1st April and the 14th August, 1918, Coigneux, a small village about 16 miles S.W. of Arras, lay some 6 miles behind the British front line. At the commencement of the German offensive in 1918 the ground on three sides of the village was hastily prepared for defence, and a triple line of trenches with many branches (known as the “Red Line”) was constructed. At first these trenches were only about 4 feet deep, but in June and July some of them were further excavated to a total depth of 6 feet. They were never manned by the infantry, and the parapets of the trenches were never disturbed. As officer in charge of the 42nd Division Observers, I lived in the neighbourhood of Coigneux from the middle of April till the middle of August, 1918. I had, therefore ample opportunity in the intervals of military duty to inspect the excavations, especially during the period of their extension. I had already searched for flint implements in different parts of France. And in June 1918, a kind suggestion from Reginald A. Smith, Esq., F.S.A., made me pay special attention to this excavated ground.