If this pure type originated in the southern tributaries of the San Juan as the Chaco and migrated to the northern we would expect in the latter more distinctly southern objects, as shell ornaments, turquoise mosaics, and a great variety of pottery of a southern type.
The pure or unit type is believed to be autochthonous in the San Juan Basin and characteristic of a middle phase of architectural development, the highest north of Mexico. It is self-centered and has preserved its characteristics over an extensive area, influencing regions far beyond.
The evolution of this type took place in the region mentioned before the fifteenth century of the Christian era. Traces of its influence have persisted into the country of mixed pueblos down to the present time, but the architectural skill has deteriorated and shows evidence of acculturation[58] from sources outside the San Juan area where it originated.
One word in regard to the adjectives, prehistoric and historic, applied to southwestern ruins. They are relative ones and obtained from data somewhat diverse in character. Casa Grande on the Gila was called a ruin when first seen by the European. It was inhabited in prehistoric times. From documentary evidence the historian learns that certain other buildings were not inhabited at the advent of the Spaniards, and if their statements are trustworthy these also are prehistoric. Legends of modern Pueblos claim that certain other ruins were inhabited houses of their ancestors before the coming of the white man. The author sees no good reason to throw this evidence out of court without investigation because some of the incidents in it betray late introduction. Many other ruins are classified as prehistoric from the purely negative, but not decisive, evidence that no objects of European make have been found in them. The ruin Sun Temple, on the Mesa Verde, is considered prehistoric from the fact that a tree with over 360 annual rings of growth was found growing on top of its highest wall. We are justified in calling this a prehistoric ruin.
The evidences that villages, cliff-dwellings, castles and towers, and other types considered in this article antedate the advent of the white man are as follows: No historian has recorded an inhabited building of this form in this or other regions; no objects of European manufacture have been found in them, and the buildings and pottery which characterize them are different from those of any inhabited when the Spanish entered the Southwest.
The complex, which is thought to be the highest form of pueblo architecture, is composed of the following elements united: (1) Several “pure types”[59] representing a religio-sociological complexion of the inhabitants; (2) towers of various forms—round, D-shaped, and rectangular; (3) the great houses; (4) unit type in cave. In Cliff Palace these four types occur united in a pueblo built in a natural cave; in Mud Spring Ruin two and possibly three of these types are found in one open-air village, more spread out as site permits. In Aztec Spring and Mitchell Spring pueblos the arrangement is more defined. In the cluster at the head of South Fork of Square Tower Canyon we have all the elements united in Hovenweep House and Hovenweep Castle. Unit type House shows the single-unit type with tower near by; in Twin Towers we have the great house with cave pueblo and towers separated. Several other towers isolated from other types also occur.
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.