complicated than the so-called small house. It is what the author has called the pure type which is structurally different from the “small house,” the so-called archaic form of the mixed pueblos of the Rio Grande. This unit type is likewise unlike the small house of the Little Colorado, including those of the Zuñi Valley and the Hopi Wash, although the Hopi kivas show the influence of the Mesa Verde culture in the persistence of the ceremonial opening in the floor called the sipapu. A cluster of small houses or the village such as we find at Mummy Lake on the Mesa Verde is composed of several scattered members, each containing for the religious and secular life the “pure type” rooms constructed on the same plan. In a village like the Aztec Spring House several unit buildings are united, forming one community house larger than the rest, which was the dominant one of the village, the remaining houses being smaller and scattered. Aztec Spring, Mitchell Spring, and Mud Spring villages show a similar consolidation of units with outlying smaller houses, and the number of units in such a union is believed to be indicated by the number of circular rooms, or kivas. Thus, four kivas might be supposed to indicate four consolidated social units. The complete concentration of several unit pueblos into one or more large communal buildings[56] is also found in several cases in the area we have studied, but we must look to the great ruin at Aztec or those on the Chaco Canyon for examples of almost complete amalgamation. Thus these large pueblos where an almost complete consolidation has occurred have resulted from a fusion or condensation of what might have formerly been a rambling village composed of several separate units. This clustering of small separated houses in a village is not peculiar to the San Juan but exists elsewhere in the Southwest, as in the Rio Grande region, where, however, the structure of each component small house is different. These separate mounds do not indicate the unit type as defined, and the Rio Grande pueblo of modern date has its kiva separated from the house masses, which have grouped themselves in rectangular lines or rooms surrounding courts. There are, perhaps, examples in this region where a circular kiva is found embedded in house masses, but these are so few in number that they may possibly be regarded as incorporate survivals due to acculturation.