In the southern part of the region here treated bowlder-marked sites are more clearly marked and more easily distinguished than in the northern part, partly perhaps because in that section the normal ground
surface is smoother than in the northern section and affords a greater contrast with the site itself. Plate XXXIII shows one of these bowlder-marked sites which occurs a little below Limestone creek, on the opposite or eastern side of the river. It is typical of many in that district. It will be noticed that the bowlders are but slightly sunk into the soil, and that the surface of the ground has been so slightly disturbed that it is practically level; there is not enough débris on the ground to raise the walls 2 feet. The illustration shows, in the middle distance, a considerable area of bottom land which the site overlooks. In plan this site shows a number of oblong rectangular rooms, the longer axes of which are not always parallel, the plan resembling very closely the smaller stone village ruins already described. It is probable that the lack of parallelism in the longer axes of the rooms is due to the same cause as in the village ruins, i.e., to the fact that the site was not all built up at one time.
The illustration represents only a part of an extensive series of wall remains. The series commences at the northern end of a mesa forming the eastern boundary of the Rio Verde and a little below a point opposite the mouth of Limestone creek. The ruins occur along the western rim of the mesa, overlooking the river and the bottom lands on the other side, and are now marked only by bowlders and a slight rise in the ground. But few lines of wall are visible, most of the ruins consisting only of a few bowlders scattered without system. From the northern end of the mesa, where the ruins commence, traces of walls can be seen extending due southward and at an angle of about 10° with the mesa edge for a distance of one-fourth of a mile. Beyond this, for half a mile or more southward, remains of single houses and small clusters occur, and these are found in less abundance to the southern edge of the mesa, where the ruin illustrated occurs. The settlement extended some distance east of the part illustrated, and also southward on the slope of the hill. Two well-marked lines of wall occur at the foot of the hill, on the flat bottom land, but the slopes of the hill are covered with bowlders and show no well-defined lines. Scattered about on the surface of the ground are some fragments of metates of coarse black basalt and some potsherds, but the latter are not abundant.
The bowlders which now mark these sites were probably obtained in the immediate vicinity of the points where they were used. The mesa on which the ruin occurs is a river terrace, constructed partly of these bowlders; they outcrop occasionally on its surface and show clearly in its sloping sides, and the washes that carry off the water falling on its surface are full of them.
In the northern end of the settlement there are faint traces of what may have been an irrigating ditch, but the topography is such that water could not be brought on top of the mesa from the river itself. At the southern end of the settlement, northeast of the point shown in the illustration, there are traces of a structure that may have been a
storage reservoir. The surface of the mesa dips slightly southward, and the reservoir-like structure is placed at a point just above the head of a large wash, where a considerable part of the water that falls upon the surface of the mesa could be caught. It is possible that, commencing at the northern end of the settlement, a ditch extended completely through it, terminating in the storage reservoir at the southern end, and that this ditch was used to collect the surface water and was not connected with the river. A method of irrigation similar to this is practiced today by some of the Pueblo Indians, notably by the Hopi or Tusayan and by the Zuni. In the bottom land immediately south of the mesa, now occupied by several American families, there is a fine example of an aboriginal ditch, described later.
In the vicinity of the large ruin just above Limestone creek, previously described, the bowlder-marked sites are especially abundant. In the immediate vicinity of that ruin there are ten or more of them, and they are abundant all along the edge of the mesa forming the upper river terrace; in fact, they are found in every valley and on every point of mesa overlooking a valley containing tillable land.
It is probable that the bowlder-marked ruins are the sites of secondary and temporary structures, erected for convenience in working fields near to or overlooked by them and distant from the home pueblo. The character of the sites occupied by them and the plan of the structures themselves supports this hypothesis. That they were connected with the permanent stone villages is evident from their comparative abundance about each of the larger ones, and that they were constructed in a less substantial manner than the home pueblo is shown by the character of the remains.
It seems quite likely that only the lower course or courses of the walls of these dwellings were of bowlders, the superstructure being perhaps sometimes of earth (not adobe) but more probably often of the type known as “jacal”—upright slabs of wood plastered with mud. This method of construction was known to the ancient pueblo peoples and is used today to a considerable extent by the Mexican population of the southwest and to a less extent in some of the pueblos. No traces of this construction were found in the bowlder-marked sites, perhaps because no excavation was carried on; but it is evident that the rooms were not built of stone, and that not more than a small percentage could have been built of rammed earth or grout, as the latter, in disintegrating leaves well-defined mounds and lines of debris. It is improbable, moreover, that the structures were of brush plastered with mud, such as the Navajo hogan, as this method of construction is not well adapted to a rectangular ground plan, and if persistently applied would soon modify such a plan to a round or partially rounded one. Temporary brush structures would not require stone foundations, but structures composed of upright posts or slabs, filled in with brush and plastered with mud, and designed to last more
than one farming season, would probably be placed on stone foundations, as the soil throughout most of the region in which these remains occur is very light, and a wooden structure placed directly on it would hardly survive a winter.