MINDELEFF ] DEVELOPMENT OF PUEBLO ARCHITECTURE Oil 
acter of the site occupied, such as the Tusayan villages of today. 
Within each of these classes there are varieties, and there are also 
secondary types which pertain sometimes to one, sometimes to the 
other, and sometimes to both. Such are the cliff ruins, the cayate 
lodges, and the single house remains. 
The unit of pueblo architecture is the single cell, and in its develop- 
ment the highest point reached is the aggregation of a great number 
of such cells into one or more clusters, either connected with or adjacent 
to each other. These cells were all the same, or essentially so; for while 
differentiation in use or function had been or was being developed at 
the time of the Spanish conquest, differentiation in form had not been 
reached. The kiva, of circular or rectangular shape, is a survival and 
not a development. 
Large aggregations of many cells into one cluster are the latest 
development of pueblo architecture. They were immediately preceded 
by a type composed of a larger number of smaller villages, located on 
sites selected with reference to their ease of defense, and apparently 
the change from the latter to the former type was made at one step, 
without developing any intermediate forms. The differences between 
the largest examples of villages on defensive sites and the smallest 
appear to be only differences of size. Doubtless in the early days of 
pueblo architecture small settlements were the rule. Probably these 
settlements were located in the valleys, on sites most convenient for 
horticulture, each genus occupying its own village. Incursions by neigh- 
boring wild tribes, or by hostile neighbors, and constant annoyance 
and loss at their hands, gradually compelled the removal of these little 
villages to sites more easily defended, and also forced the aggregation 
of various related gentes into one group or village. Ata still later 
period the same motive, considerably emphasized perhaps, compelled 
a further removal to even more difficult sites. The Tusayan villages 
at the time of the Spanish discovery were located on the foothills of 
the mesas, and many pueblo villages at that period occupied similar 
sites. Actuated by fear of the Ute and Comanche, and perhaps of 
the Spaniards, the inhabitants soon after moved to the top of the 
mesa, where they now are. Many villages stopped at this stage. Some 
were in this stage at the time of the discovery—Acoma, for example. 
Finally, whole villages whose inhabitants spoke the same language 
combined to form one larger village, which, depending now on size 
and numbers for defense, was again located on a site convenient for 
horticulture. 
The process sketched above was by no means continuous. The pop- 
ulation was in slow but practically constant movement, much the same 
as that now taking place in the Zuni country; it was a slow migration. 
Outlying settlements were established at points convenient to cultiva- 
ble fields, and probably were intended to be occupied only during the 
summer. Sometimes these temporary sites might be found more con- 
venient than that of the parent village, and if would gradually come 

