Altogether the constructive expedients employed in De Chelly suggest the introduction of plans and methods adapted to other regions and other conditions into a new region with different requirements, and that occupancy of the latter region did not continue long enough to conform the methods to the new conditions. KIVAS OR SACRED CHAMBERS The kivas, or estufas as they formerly were called, are sacred chambers in which the civil and religious affairs of the tribe are transacted, and they also form a place of resort, or club, as it were, for the men. Their functions are many and varied, but as this subject has already been discussed at length[17] it need not be enlarged upon here. In Tusayan the kivas are rectangular and separated from the houses; in Zuni and in some other pueblos they are also rectangular, but are incorporated in the house clusters--a feature doubtless brought about by the repressive policy of the Spanish monks. In some of the pueblos, as in Taos, they are circular, and in many of the older ruins the same form is found. In the large ruins of Chaco canyon the kivas occur in groups arranged along the inner side of the rooms; always, where the ground plan is such as to permit it, arranged on the border of an inner court. In Canyon de Chelly the kivas are always circular and are placed generally on the outer edge of the settlement, which is usually the front. [Footnote 17: 8th Ann. Rept. Bur. Eth., "A study of Pueblo architecture in Tusayan and Cibola," by Victor Mindeleff; Washington, 1891.] As the function of the kivas is principally a religious one, they are found only in permanent villages where religious ceremonies were performed. They are never found in subordinate settlements, or farming villages, or outlooks, unless such settlements came to be inhabited all the year--in other words, until they became permanent villages. The habits and requirements of the Pueblo people make it essential that a permanent village should have one or more kivas, and we have in the presence of these structures a criterion by which the character of a village or ruin may be determined. As the kivas in De Chelly are always circular, they can generally be easily distinguished. The circular kiva is unquestionably a survival in architecture--a relic of the time when the Pueblo people dwelt in circular lodges or huts--and its use in conjunction with a rectangular system entailed many difficulties and some awkward expedients to overcome them. The main problem, how to use the two systems together, was solved by inclosing the circular chamber in a rectangular cell, and this expedient aided in the solution of the hardly less important problem of roofing. The roof of the kiva was the roof of the chamber that inclosed it.