282 DESIGNS ON HOPI POTTERY [BTH. ANN. 33 
partially or wholly subterranean. When above ground their walls 
were supported by upright logs in which canes or brushes were woven 
and covered with mud, the roofs being made of cedar bark or straw 
overlaid with adobe. 
The pottery of this early prehistoric epoch was smooth, painted 
mainly with geometric patterns, corrugated, or indented. Rectilinear 
or curved lines constituted the majority of the superficial decorations 
and life designs were few or altogether wanting. In addition to 
these architectural and ceramic characteristics, this prepuebloan 
cultural stage was distinguished by many other features, to mention 
which would take us too far afield and would be out of place in this 
article. Evidences of this stage or epoch occur everywhere in the 
Southwest and survival of the archaic characters enumerated are 
evident in all subsequent epochs. 
The so-called “ unit type” or pure pueblo culture grew out of this 
early condition and was at first localized in northern New Mexico 
and southern Colorado, where it was autochthonous. Its essential 
feature is the terraced communal house and the simplest form of the 
pueblo, thé “unit type,” first pointed out by Dr. T. Mitchell Prud- 
den—a combination of dwelling houses, with a man’s house or kiva 
and a cemetery. The dwellings are made of stone or clay and are 
terraced, the kiva is subterranean and circular, embedded in or 
surrounded by other rooms. The “unit type” originated in Colo- 
rado and, spreading in all directions, replaced the preexisting houses 
with fragile walls. Colonists from its center extended down the 
San Juan to the Hopi country and made their way easterly across 
the Rio Grande and southerly to the headwaters of the Gila and 
Little Colorado, where they met other clans of specialized pre- 
puebloan culture who had locally developed an architecture of Great 
House style characteristic of the Gila and Salt River Valleys. 
The essential differences between the terraced pueblo and the pre- 
viously existing fragile-walled house culture are two: The terraced 
architecture results from one house being constructed above an- 
other, the kiva or subterranean ceremonial room being separated or 
slightly removed from the secular houses. 
An explanation of the origin of the terraced pueblo is evident. 
This form of house implies a limited site or a congestion of houses 
on a limited area. An open plain presents no limitation in lateral 
coristruction ; there is plenty of room to expand in all directions to 
accommodate the enlargement which results as a settlement increases 
in population. In a cave conditions are otherwise; expansion is lim- 
ited. When the floor of the cavern is once covered with rooms the 
only additions which can possibly be made must be vertically. 
In protection lies the cause of the development of a terraced 
architecture such as the pueblos show, for the early people con- 
