In the classification by Morley and Kidder and the majority of writers,
sites rather than structural features are adopted as a basis although
all recognized that large cliff-dwellings like Cliff Palace are
practically pueblos built in caves. In the following classification
more attention is directed to differences in structure than to
situation, notwithstanding the latter is convenient for descriptive
purposes.
1. Villages or clusters of houses, each having the form of the pure
pueblo type. The essential feature of the pure type is a compact
pueblo, containing one or more unit types, circular kivas of
characteristic form, surrounded by rectangular rooms. These units,
single or consolidated, may be grouped in clusters, as Mitchell Spring
or Aztec Spring Ruins; the clusters may be fused into a large building,
as at Aztec or in the community buildings on Chaco Canyon.
2. Cliff-houses. These morphologically belong to the same pure type as
pueblos; their sites in natural caves are insufficient to separate them
from open-sky buildings.
3. Towers and great houses. These buildings occur united to
cliff-dwellings or pueblos, but more often they are isolated.