Fig. 1

Geographical setting. a Location of the Boncourt—Queue au Loup site within the Ajoie district and the Canton Jura, NW Switzerland. b Close-up of the Queue au Loup site and Highway A16 (dotted line). The area surrounded by the thick black line is the construction site of the customs platform (“plate-forme douanière”) between Switzerland and adjacent France. c Detail of the construction area of the customs platform. The area of the emergency excavation (excavation area 10) is also shown in Fig. 3a. d Aerial photograph of the construction site after the emergency excavation had been terminated