This diagnostic operation completes the data from the basement of Senlis. It identifies the existence of one or more apparantly open-air quarries dating to the end of the Early Middle Ages. This extraction site is located outside the late Gallo-Roman enclosure, in the immediate vicinity of the Saint-Maurice gate whose date remains uncertain. Dating from the first half of the eleventh century, this quarry was able to supply prestigious construction sites – for repairs and modifications of the Carolingian castle, the octagonal chapel of the cathedral… - and much more modest constructions. The remains of the occupation of the Later Middle Ages are few and are limited to a pit and a wall of which two phases have been identified. It is impossible to characterize precisely the nature of these occupations. Traduction : John LYNCH