This is the locus just above the floor--a (surprisingly) dark brown silt, and very rocky with both large and small stones. The locus covers much of the area formerly covered by loci 15 and 17, although it does not extend as far to the south. At the bottom of the locus, we're encountering clay lenses and some burnt earth. It appears that the flagstone floor is thus just about resting on the surface of the floor.