Philippe Muchez and Dominique Similox-Tohon kept busy this week, carrying out 17 boreholes with the Ramguts drilling device between the Upper Agora and the Potters' Quarter, along the resistivity profiles that were measured during the campaign of 2002. In these profiles, five resistivity layers and several faults were identified. The aim of the drilling was to specify the lithological character of these five layers and the offset along the faults.

Layer 1 of the resistivity profiles corresponds with recent scree deposits. Layer 2 consists of loose brown sand with ceramics and limestone fragments. It represents syn- or post-occupation colluvium. In several drillings, formerly non-identified layers of volcanic tuff are reached below layer 2. The top of these volcanic tuff deposits is often altered to brown clay. In these tuff deposits, colluvial deposits consisting of limestone fragments cemented by brown clay may be intercalated. Layer 3 is characterised by sequences of often weathered, beige limestone fragments in compact brown clay. This layer is interpreted as a pre-occupation colluvium (scree). In one deep borehole (5.25 m), compact brown clay with intensely weathered limestone and volcanic tuff fragments is present below the tuffs. It could represent part of the peri-glacial deposits, which occurs widespread in the area. Layers 4 and 5 could not be reached. The offset of the different layers along the fault could not be documented on account of the often shallow depth of the boreholes caused by the presence of large limestone fragments in layer 1 and 2.