170 THE CLIFF RUINS OF CANYON DE CHELLY _ [ETH.4nn.16 
roughly plastered where they meet. Instances of the use of stone in 
this way are not uncommon in the pueblo country, aud there are a num- 
ber of examples in De Chelly. 
As before stated, the typical Navaho burial cist is of domeshape. The 
roof or upper portion is supported on sticks so arranged as to leave a 
small square opening in the top. Apparently at some stage in its exist- 
ence this hole is closed and sealed, but examples were examined which 
were very old and one which was but twenty-four hours old, but in 
neither case was the opening closed. Doubtless the opening has some 
ceremonial significance; it is not of any actual use, as it is too small to 
permit the passage of a human body. Plate Lxir shows a typical cist 
in good order and another such broken down. These examples oceur 
at the point marked 6 on the map, in the ruin shown in plate LI. 
This site is of comparatively easy access, and there are many others 
equally easy or even more so, but, on the other hand, there are many 
sites which now seem to be wholly inaccessible. 
DEFENSIVE AND CONSTRUCTIVE EXPEDIENTS 
The cliff ruins have always been regarded as defensive structures, 
sometimes even as fortresses, but in De Chelly whatever value they 
have in this respect is due solely to the sites they oceupy. There are 
many places here where slight defensive works on the approaches to 
sites would increase their value a hundredfold, but such works were 
apparently-never constructed. Furthermore, the ruins themselves 
never show even a suggestion of the influence of the defensive motive, 
except in the two possible instances already mentioned. The ordinary 
or dwelling-house plan has not been at all modified, not even to the 
extent that it has in the modern pueblos. If the cliff ruins were defen- 
sive structures it would certainly seem that an influence strong enough 
to bring about the occupancy of such inconvenient and unsuitable sites 
would also be strong enough to bring about some modifications in the 
architecture, modifications which would render more suitable sites 
available. The influence of the physical environment on pueblo archi- 
tecture, and the sensitiveness of the latter to such influence, has already 
been commented on. Moreover, it also has been stated that, so far as 
known, but one instance oceurs in the canyon where provision was 
made for the storage of water; yet without water the strongest ‘for- 
tress” in the eanyon could not withstand a siege of forty-eight hours. 
Further, assuming that the structures were defensive, and well pre- 
pared to resist attack, if necessary, for several days, only a few such 
attacks would be required to cause their abandonment, for the crops on 
the canyon bottom, practically the sole possessions of the dwellers in 
the canyon, would necessarily be lost. 
These are some of the difficulties that stand in the way of the assump- 
tion that the cliff ruins were defensive structures or permanent homes. 
If, however, we adopt the hypothesis that they were farming outlooks 
