Locus 13 is a soil deposit lens within the general fill locus 09, which is the highly organic fill within the stone gutter/channel locus 16. Though Locus 09 was fairly undifferentiated in the northern part of the trench (where the channel runs n-s) it became deeper in the southern trench and subdivided into layered lenses. Locus 13 had a slick black layer on top and a gray-orange clayey silt underneath. the layer slopes-laying highest near the southern edge of locus 10 and lowest near the southwest trench corner.