Three terraces or tiers containing rooms, as shown in the accompanying ground plan, were revealed by excavations in this talus. At the western extension, where the second and third terraces cease, the tops of large rocks begin at the level of the fourth terrace, and on the southern end the first terrace is absent. At the western extremity, the large blocks of rock having dropped down entire from the side of the cliff, fill the interval elsewhere occupied by the lower terraces, and their tops now form a ledge upon which rest the foundations of rooms level with the plaza. It is thus evident that whereas the front wall of Spruce-tree House is simple, the level of the kiva roofs and floors of buildings above ground being continuous, the front of Cliff Palace is complicated, being at different levels, consisting of terraces in the talus. As one approached Cliff Palace, when inhabited, it must have presented, from below, an imposing structure, the lower terraces being occupied by many large kivas above which rose lofty buildings arranged in tiers, several being four stories high. Although the height was much increased by the presence of huge foundation blocks of sandstone, from the lowest terrace to the highest room there were seven floor levels, including those of the kivas in the terraces. An examination of Cliff Palace cave shows that from the southern end to the section over the main entrance its roof arches upward and that the part over the rear of the ruin is lower than that over its front. Between the lower and upper roof levels there is a sharp break formed by a vertical cleavage plane. Where this plane joins the upper level there is a shelf forming a recess in which has been constructed a row of ledge rooms.[17] [Footnote 17: One of these rooms had been chosen by eagles for their nests, but both nests and eggs were abandoned by the birds after the repair work was begun.] The great rock roof arching over Cliff Palace is broken about midway between the vertical plane above mentioned and the rim by another and narrower vertical plane where no ledge exists. Here multitudes of swallows had made their home, and there are wasps' nests in several places. [Illustration: PLATE 8 FROM SURVEY BY R. G. FULLER GROUND PLAN] PREHISTORIC TRAILS TO CLIFF PALACE