INTRODUCTION

It was clear that the geometry of the Fontéchevade Cave system was likely much more complex than it appeared initially. Other caves in this area, particularly La Chaise, demonstrate complexity with their multitude of subsidiary chambers, entrances, and connecting passageways. To some extent, the complexity of Fontéchevade is apparent in Henri-Martin's map of the site. Just inside the entrance of the cave there is a side branch, which she labeled the Diverticule. Just behind the main section, there is another side branch that is too full of sediment to enter, and likewise the very back of the cave ends with apparent passageways choked with sediment. In part to look for additional caves in the area and in part to look for alternative entrances to Fontéchevade, we conducted an electrical resistivity survey of the area immediately above and adjacent to the entrance to the cave.

METHODOLOGY

Electrical resistivity is a well-established remote sensing technique that has been applied to archaeological situations for some time, typically to map changes in lithology and to locate buried features (Ellwood and Harrold 1993; Ellwood et al. 1993, 1995). The usefulness of electrical resistivity is based on the fact that soils and rocks vary in the degree to which they are able to conduct electrical current. The ability of soils and rocks to conduct current is controlled by several factors, including moisture content, clay content, porosity, and the presence of free ions (Ellwood and Harrold 1993).