Ruin B (pl. 20, _b_), situated a short distance north of Ruin A, also stands on the canyon rim. The north wall is entire, but the south wall has fallen. What remains indicates that the ruin was about square, with corners on the north side rounded, imparting to it a semicircular form. The entrance into this room may have been through the floor. TOWERS [C AND D] These towers (pl. 23, _a_, _b_) show some of the finest masonry known in this region, being constructed on fallen bowlders which their foundations almost completely cover. Holly Tower (pl. 23, _b_) measures 16 feet high and 21 feet in diameter. It is 7 feet wide, its top rising to a height level with that of the mesa on which stand buildings already considered. One of the two rooms of this tower is narrower and wider than the other, shown in an offset as if constructed at a different time. Its foundations are 17 feet long by 8 feet wide, the highest wall measuring, at the southeast corner, 12 feet 8 inches. There is a fine doorway, wide above and narrow below, in the north wall. The approach at present is difficult on account of the height of the rock on which it stands, but there are evidences of former footholes. HOLLY HOUSE Several broken-down walls, some of which are over 6 feet high, situated east of Ruin A, appear to belong to a pueblo of considerable size (fig. 11, _E_, _F_), but the large foundation rock on which it is situated has settled, its top having separated from the edge of the canyon, so that the corner of the building (_F_) is out of plumb. The walls on the adjoining cliff are also much broken down, although several sections of them rise a few feet above the general surface. The cause of this change in level of the base may have been an earthquake or the settling or sliding of the bowlder on the talus down the hill. The united building appears to have been a pueblo of rectangular form. Its walls are so broken down that it was not possible to determine its exact dimensions. RUINS IN HACKBERRY CANYON HORSESHOE HOUSE The large building in Hackberry Canyon, one of the terminal spurs of Bridge Canyon, a mile northeast of the cluster in Holly Canyon, is particularly instructive from the fact that surrounding the remains of a circular tower, for two-thirds of its circumference, is a concentric wall with compartments separated by radial partitions (fig. 12, 1). [Illustration: FIG. 12.—Horseshoe (Hackberry) Canyon.]