For the past sixty years the environs of the village of Spiennes, south-east of Mons in Hainault, Belgium, have continually provided archaeologists with evidence in great abundance. The banks of the Trouille valley have been inhabited almost continuously since man first appeared on the earth, that is since the beginning of quaternary times. The relics of these successive occupations by man are distributed according to their date on three of the four terraces, at the respective elevations of 266, 233, 100, and 7 feet above the river level. On the 233 ft. terrace is found an industry of considerable interest, still almost entirely of eolithic character and typical of the first transition from the primitive industry to the palaeolithic. On the 100 ft. terrace a seam of flints at the base of the early alluvium contains an enormous development of the first palaeolithic industry which was named pre-Chelles by the late Professor Commont. This is the industry corresponding to the Piltdown skull in England, and to the second (133 ft.) and third (83 ft.) terraces of the Somme valley at St. Acheul. It also occurs on the high ground of North Kent (Swanscombe, Galley Hill, etc., on the 100 ft. terrace).