For what purpose these buildings were erected, and in what relation they stood to _B_, I am unable to determine. Some of them appeared to have doors opening to the east.[115] Beyond _f_ the ground rises suddenly. The floor of those structures is, in some instances, formed of a black or red loam. I excavated one of those, or, rather, dug into it, to the depth of one metre. The surface had shown traces of a fire built in the centre, and I found also, at the depth of nearly two feet, that the dark soil was traversed by a band of charcoal, fragments of burnt and blackened pottery, and some splinters of bone. Below it the soil was dark red. Whether there was a buried hearth at that depth, or whether the traces of fire were due to an original destruction of woodwork through combustion, the _débris_ subsequently covering them with clay, I am unable to judge.[116] In all of them, of course, pottery and obsidian were found. I have already stated that the _mesilla_ dips to the south-west; that there is a depression along the northern end of its "neck;" and that from _f_ the rocks bulge upwards again. All this contributes to concentrate the drainage of the entire cliff-top, as far north of the church as it was inhabited, in the hollow where the gate of the general enclosure is placed. This gate was therefore not only a passage-way, but also the water-gap or channel through which the _mesilla_ was finally drained into the bottoms of the Arroyo de Pecos. [Illustration: PLATE IV PLAN OF BUILDING A.]