The Holly Canyon group shows the types separated. The great house is represented by Holly Castle; the towers are situated on huge bowlders. The unit type of this group is represented by Holly House, the foundation of part of which has fallen, covering the ruins of another pueblo of the unit type formerly in the cave below. The Hackberry group is also composed of three elemental types separated; the great house is represented by Hackberry House, the unit type by the cliff-dwelling below and by the pueblo on the opposite side of the gulch, and the towers by isolated towers. A similar analysis may be made of other ruins. Sometimes the component types are united; often one type only occurs, the others being absent. The union of all is best marked in the northern tributaries of the San Juan, as at Aztec, and in the southern tributaries, as at Chaco Canyon and Chelly Canyon. These pueblos, whether in the open or in caves, belong to the pure or concentrated multiple unit type. Some light may be shed on the probable process of consolidation of the individual units of a community house by a comparative study of the pueblos on the East Mesa of the Hopi. Hano, for instance, was settled by a group of Tanoan clans about 1710 A. D. The list of Hano clans that originally came to the East Mesa is known from legends and the present localization of their survivors has been indicated in the author’s article on “The Sun’s Influence on the Form of Hopi Pueblos.”[60] In 1890 Hano was composed of four blocks of rooms, each housing one or more clans. Earlier there were six, one of which had fallen into disuse, a few less than the traditional number of clans. When the colonists arrived, they settled near Coyote Spring, the houses of which are now covered with drifted sand, but when they constructed their village on the mesa at the head of the trail each house of a cluster housed a clan. Increase in population, both internal and external, led to the union and enlargement of these houses so that they inclosed a central plaza. A similar growth has taken place in Sichomovi, the pueblo halfway between Walpi and Hano; first single houses, then rows of houses with terraces on the south and east sides. Some of the original houses have been deserted and rebuilt nearer the others. Thus at Hano the Katcina clan house was north and east of the chief kiva but is now in the east row. [60] Amer. Anthrop., n. s. vol. viii, no. 1, 1906. In the same way we may suppose that in a consolidation of a community dwelling several units may have drawn together and united. There is evidence of a union of this kind in many ruins in the Southwest.