In the valley of the Rio Verde the profitable use of adobe at the present time is approximately limited northward by the thirty-fourth parallel, which crosses the valley a little below the mouth of Limestone creek. North of this latitude adobe is used less and less and where used requires more and more attention to keep in order, although on the high tablelands some distance farther northward it is again a suitable construction. South of the thirty-fourth parallel, however, adobe construction is well suited to the climate and in the valleys of Salt and Gila rivers it is the standard construction. Adobe construction (the use of sun-dried molded brick) was unknown to the ancient pueblo builders, but its aboriginal counterpart, rammed earth or pisé construction, such as that of the well known Casa Grande ruin on Gila river, acted in much the same way under climatic influences, and it is probable that its lack of suitability precluded its use in the greater part of the Verde valley. No walls of the type of those of the Casa Grande ruin have been found in the valley of the Verde, although abundant in the valleys of the Salt and Gila rivers, but it is possible that this method of construction was used in the southern part of the Verde region for temporary structures; in the northern part of that region its use even for that purpose was not practicable.
In this connection it should be noted that all the ruins herein described are of buildings of the northern type of aboriginal pueblo architecture and seem to be connected with the north rather than the south.
Plate XXXIV. Irrigating Ditch on the Lower Verde.
[ IRRIGATING DITCHES AND HORTICULTURAL WORKS.]
One of the finest examples of an aboriginal irrigating ditch that has come under the writer’s notice occurs about 2 miles below the mouth of Limestone creek, on the opposite or eastern side of the river. At this point there is a large area of fertile bottom land, now occupied by some half dozen ranches, known locally as the Lower Verde settlement. The ditch extends across the northern and western part of this area. Plate XXXIV shows a portion of this ditch at a point about one eighth of a mile east of the river. Here the ditch is marked by a very shallow trough in the grass-covered bottom, bounded on either side by a low ridge of earth and pebbles. Plate XXXV shows the same ditch at a point about one-eighth of a mile above the last, where it was necessary to cut through a low ridge. North of this point the ditch can not be traced, but here it is about 40 feet above the river and about 10 feet above a modern (American) ditch. It is probable that the water was taken out of the river about 2 miles above this place, but the ditch was run on the sloping side of the mesa which has been recently
washed out. No traces of the ditch were found east of the point shown in plate XXXIV, but as the modern acequia, which enters the valley nearly 10 feet below the ancient one, extends up the valley nearly to its head, there is no reason to suppose that the ancient ditch did not irrigate nearly the whole area of bottom land. The ancient ditch is well marked by two clearly defined lines of pebbles and small bowlders, as shown in the illustration. Probably these pebbles entered into its construction, as the modern ditch, washed out at its head and abandoned more than a year ago, shows no trace, of a similar marking.
