The composite round and square pueblo ruin is not, however, confined to this transitional type or to its comparatively restricted area wherever occurring, but is found here and there as far northward, for instance, as the neighborhood of older cliff ruins. But in such cases it seems to have been developed, as heretofore hinted, in the comparatively recent rebuilding of old rounded towns by square-house builders. Quite in correspondence with all this is the history of the development, from the round form into the square, of the kivas of the later Zuñi towns; that is, like the towns themselves, the round kivas of the earlier round towns became, first in part and then nearly squared in the composite round and square towns, and finally altogether squared in the square towns. This was brought about by a twofold cause. When the cliff dwellers became inhabitants of the plains, not only their towns, but also the kivas were enlarged. To such an extent, indeed, were the latter enlarged that it became difficult to roof them over in the old fashion of completing the upper courses of the walls with cross-laid logs, and of roofing the narrowed apex of this coping with combined rafter and stick structures; hence in many cases, although the round kiva was rigidly adhered to, it was not unfrequently inclosed within a square wall in order that, as had come to be the case in the ordinary living rooms, rafters parallel to one another and of equal length might be thrown across the top, thus making a flat roof essentially like the flat terrace roofs of the ordinary house structure. It is not improbable that the first suggestion of inclosing the round kiva in a square-walled structure and of covering the latter with a flat roof arose quite naturally long before the cliff dwellers descended into the plains. It has been seen that frequently, in the larger and longest occupied cliff-towns, the straight-walled houses grew outward wholly around the kivas; and when this occurred the round kiva was thus not only surrounded by a square inclosure--formed by the walls of the nearest houses,--but also it became necessary to cover this inclosing space with a flat roof, in order to render continuous the house terrace in which it was constructed. Still, the practice never became general or intentional in the earlier cliff-towns; probably, indeed, it became so in the now ruined round towns only by slow degrees. Yet it needed after this (in a measure) makeshift beginning only such influence of continued intercourse between the square-house building people and these round-town building people to lead finally to the practical abandonment by the latter of the inner round structure surviving from their old-fashioned kivas, and to make them, like the modern Zuñi kiva, square rather than round.