226 PUEBLO ARCHITECTURE. 
form, suitable for use in the simple masonry of the pueblos without re- 
ceiving any artificial treatment. The walls themselves give an exag- 
gerated idea of finish, owing to the care and neatness with which the 
component stones are placed. Some of the illustrations in the last chap- 
ter, from photographs, show clearly that the material of the walls was 
much ruder than the appearance of the finished masonry would suggest, 
and that this finish depended on the careful selection and arrangement 
of the fragments. This is even more noticeable in the Chaco ruins, in 
which the walls were wrought to a high degrees of surface finish. The 
core of the wall was laid up with the larger and more irregular stones, 
and was afterwards brought to a smooth face by carefully filling in and 
chinking the joints with smaller stones and fragments, sometimes not 
more than a quarter of an inch thick; this method is still roughly fol- 
lowed by both Tusayan and Cibolan builders. 
Although many details of construction and arrangement display 
remarkable adaptation to the physical character of the country, yet the 
influence of such environment would not alone suffice to produce this 
architectural type. In order to develop the results found, another ele- 
ment was necessary. This element was the necessity for defense. The 
pueblo population was probably subjected to the more or less continu- 
ous influence of this defensive motive throughout the period of their 
occupation of this territory. A strong independent race of people, who 
had to fear no invasion by stronger foes, would necessarily have been 
influenced more by the physical environment and would have progressed 
further in the art of building, but the motive for building rectangular 
rooms—the initial point of departure in the development of pueblo 
architecture—would not have been brought into action. The crowding 
of many habitations upon a small cliff ledge or other restricted site, re- 
sulting in the rectangular form of rooms, was most likely due to the 
conditions imposed by this necessity for defense. 
The general outlines of the development of this architecture wherein 
the ancient builders were stimulated to the best use of the exceptional 
materials about them, both by the difficult conditions of their semi-desert 
environment and by constant necessity for protection against their 
neighbors, can be traced in its various stages of growth from the primi- 
tive conical lodge to its culmination in the large communal village of 
many-storied terraced buildings which we find to have been in use at 
the time of the Spanish discovery, and which still survives in Zuni, per- 
haps its most striking modern example. Yet the various steps have re- 
sulted from a simple and direct use of the material immediately at hand, 
while methods gradually improved as frequent experiments taught the 
builders more fully to utilize local facilities. In all cases the material 
was derived from the nearest available source, and often variations in 
the quality of the finished work are due to variations in the quality of 
the stone near by. The results accomplished attest the patient and per- 
sistent industry of the ancient builders, but the work does not display 
great skill in construction or in preparation of material. 
