528 The Ancient Pucblos. [ August, 
Puéblos or towns, and secondly, Defensive structures. Valley ruins 
were by far the most extensive, sometimes covering miles of bot- 
tom land, in an almost unbroken series of huge buildings, but 
they were not nearly so numerous as the cliff houses. The 
ancient tribe or tribes congregated together along the water- 
courses for sociability (man being a gregarious animal) and for 
mutual protection. 
The cliff-houses are of three sorts: First, dwellings; secondly, 
watch-towers ; and, thirdly, caches or store-houses. These were 
built among the sandstone bluffs and crags of the cañons ; at 
every altitude and in every conceivable position. From the base 
of an almost vertical wall, up to the very summit of the mésa, a 
distance, sometimes of over a thousand feet, these human eyries 
are perceivable, perched sometimes on almost or quite inaccessi- 
ble shelves, or on the very pinnacle of some isolated bowlder, 
whose sides look down perpendicularly for hundreds of feet. In 
every imaginable condition of location, they existed and the 
beholder is impressed with a feeling of awe, in simply gazing on 
the works of the intrepid architects ; on the places where human 
beings once dwelt; places which now are wholly out of reach of 
the explorer. The walls of the buildings are sometimes built 
along the ledges of rock, on the horizontal foot-holds which oc- 
cur among the cliffs; but far more frequently, the natural caves 
and hollows (formed by the erosion of the atmosphere) were 
converted into dwelling places. 
One of the most noticeable features of all of these cliff-struc- 
tures, was the evident desire on the part of their proprietors to 
conceal them from view, and this is shown in the prevailing cus- 
tom of building in secluded spots, and in imitating, as accurately 
as possible, in the architecture, the general appearance of the 
surrounding rocks. In many cases, indeed, this simulation 
of texture and color has been rendered so perfect, that the ruins 
are entirely over-looked, unless brought to view through a field- 
glass. | 
Clearly, then, there must have been a cause for these precau- 
tions. The empire was invaded by a foreign foe, and the people 
- gradually forced southward; fleeing to the rocks at first, for 
_ refuge, but finally retiring before the advance of a powerful and 
cruel enemy. This fact is made more evident by the presence 
es numbers of aap pone and war-like weapons, in the ay 7 
