The western cluster of the ruin last mentioned, shown on the ground plan (plate XVII), has almost all its walls still standing, and the masonry, while of the same general character as that of the main cluster, is better executed. The stones composing the walls are smaller than those in the main cluster and more uniform in size, and the interstices are carefully chinked. The chinking is distinctive in that spalls were not used, but more or less flattened river pebbles. The different color and texture of these pebbles make them stand out from the wall distinctly, giving quite an ornamental effect. [Illustration: Plate XLIII. SINGLE-ROOM REMAINS ON CLEAR CREEK.] That portion of the standing wall of the ruin opposite Verde, which occurs in the saddle northeastward from the main cluster, shown on the plan in plate XVII, represents the best masonry found in this region. As elsewhere stated, this was probably the last part of the village to be built. These walls are shown in plate XLVII. It will be noticed that the stones are of very irregular shape, rendering a considerable amount of chinking necessary to produce even a fair result, and that the stones are exceptionally large. The masonry of this village is characterized by the use of stones larger than common, many of them being larger than one man can carry and some of them even larger than two men can handle. All the larger and more important ruins of this region are constructed of limestone slabs, sometimes with bowlders. The smaller ruins, on the other hand, were built usually of river bowlders, sometimes with an intermixture of slabs of limestone and sandstone but with a decided preponderance of river bowlders. This would seem to suggest that this region was gradually populated, and that the larger structures were the last ones built. This suggestion has been already made in the discussion of the ground plans, and it is, moreover, in accord with the history of the pueblo-builders farther northward, notably that of the Hopi. Plate XXI illustrates a type of bowlder masonry which occurs on Clear creek; plate XLVIII shows the masonry of the ruin at the mouth of the East Verde, and plate XVI shows that of a ruin at the month of Fossil creek. In all these examples the stone composing the walls was derived either from the bed of an adjacent stream or from the ground on which they were built, and was used without any preparation whatever; yet in the better examples of this type of masonry a fairly good result was obtained by a careful selection of the stones. A still ruder type of masonry sometimes found in connection with village ruins is shown in figure 290. This, however, was used only as in the example illustrated, for retaining walls to trails or terraces, or analogous structures.