Judging from the number of rooms, the cliffs on the left bank of the Verde must have had a considerable population when inhabited. These caverns, no doubt, swarmed with human beings, and their inaccessible position furnished the inhabitants with a safe refuge from enemies, or an advantageous outlook or observation shelter for their fields on the opposite side of the stream. The soft rock of which the mesa is formed is easily worked, and there are abundant evidences, from the marks of tools employed, that the greater part of each cave was pecked out by hand. Fragments of wood were very rarely seen in these cliff dugouts; and although there is much adobe plastering, only in a few instances were the mouths of the caves walled or a doorway of usual shape present. The last room at the southern end, near the promontory at the right of the entrance to a side canyon, has walls in front resembling those of true cliff houses and pueblos in the Red-rock country farther northward, as will be shown in subsequent pages. This group of cavate dwellings, while a good example of the cavern type of ruins, is so closely associated, both in geographical position and in archeological remains, with other types in Verde valley, that we are justified in referring them to one and the same people. The number of these troglodytic dwelling places on the Verde is very large; indeed the mesas may be said to be fairly honeycombed with subterranean habitations. Confined as a general thing to the softer strata of rock, which from its character was readily excavated, they lie side by side at the same general level, and are entered from a projecting ledge, formed by the top of the talus which follows the level of their entrances. [Illustration: FIG. 245--Plan of cavate dwelling on Rio Verde] This ledge is easily accessible in certain places from the river bed, where stones have fallen to the base of the cliff; but at most points no approach is possible, and in their impregnable position the inhabitants could easily defend themselves from hostile peoples. [Illustration: BUREAU OF AMERICAN ETHNOLOGY SEVENTEENTH ANNUAL REPORT PL. XCII ENTRANCES TO CAVATE RUINS] Whether the rock had recesses in it before the caves were enlarged would seem to be answered in the affirmative, for similar caves without evidences of habitations were observed. These, however, are as a rule small, and wherever available the larger caverns have been appropriated and enlarged by stone implements, as shown by the pecking on the walls. The enlargement of these caverns, however, would not be a difficult task, for the rock is very soft and easily worked. Entering one of these cavate rooms the visitor finds himself in a dark chamber, as a rule with side openings or passageways into adjoining rooms. Broad lateral banquettes are prominent features in the most complicated caves, and there are many recesses and small closets or cists.