The lowest story of the tower is entered from plaza B, and on the east side there are three openings, situated one over another, indicating the first, second, and third stories, but on the south side of the tower there are only two doorways. The roof of the lowest room is practically intact, showing good workmanship, but about half of its floor is destroyed. The upper walls of the second-story room have the original plaster, reddish dado below and white above. Although the third and fourth stories are destitute of floors, they are plastered. KIVAS Some of the best preserved circular ceremonial chambers (kivas) in the Southwest are to be seen in Square Tower House. The majority of the kivas belong to the pure type, distinguished by mural pilasters supporting a vaulted roof. Kiva A is particularly instructive on account of the good preservation of its roof. Its greatest diameter is 13 feet 6 inches; or, measuring inside the banquettes, 11 feet 1 inch. The interior is well plastered with many layers of brown plaster. The pilasters are six in number, one of which is double. Two depressions are visible in the smooth floor, in addition to a fireplace and a sipapu. These suggest ends of a ladder, but no remains of a ladder were found in the room. Kiva B is the largest ceremonial chamber in Square Tower House, measuring 16 feet 9 inches in diameter over all. This kiva is not only one of the best preserved, but also one of the most instructive in Square Tower House, since half of the roof, with the original cribbing, is still in place, extending completely around the periphery. It has six pilasters and as many banquettes. Where the plaster had not fallen, it was found to have several layers. [Illustration: SUN TEMPLE, A MYSTERIOUS FORM OF RUIN] PETROGLYPHS The perpendicular cliff back of Square Tower House has several different forms of incised petroglyphs. From the fact that these usually occur on the cliff above the kiva roofs, they may be regarded as connected in some way with a religious symbolism. A few petroglyphs are also found on stones set in the walls of the rooms. OAK TREE HOUSE The ruin formerly called Willow House, but now known as Oak Tree House, lies on the north side of Fewkes Canyon, in a symmetrical cave and has an upper and a lower part. The two noteworthy features of Oak Tree House are the kivas and the remnant of the wall of a circular room made of sticks plastered with adobe but destitute of stone masonry.