has seen the remains of a modern adobe house whose maximum age could not
exceed a decade or two, yet which presented an appearance of antiquity
quite as great as that of the wall remains east and southeast of the
Casa Grande ruin.

The application of the hypothesis to the map brings out some interesting
results. In the first place, it may be seen that in the lowest mounds,
such as those in the northwestern corner of the sheet, on the southern
margin, and southwest of the well-marked mound on the eastern margin,
the contours are more flowing and the slopes more gentle than in others.
This suggests that these smoothed mounds are older than the others, and,
further, that their present height is not so great as their former
height; and again, under this hypothesis, it suggests that the remains
do not belong to one period, but that the interval which elapsed between
the abandonment of the structures whose sites are marked by the low
mounds and the most recent abandonment was long. In other words, this
group, under the hypothesis, affords another illustration of a fact
constantly impressed on the student of southwestern village remains,
that each village site marks but an epoch in the history of the tribe
occupying it--a period during which there was constant, incessant
change, new bands or minor divisions of the tribe appearing on the
scene, other divisions leaving the parent village for other sites, and
the ebb and flow continuing until at some period in its history the
population of a village sometimes became so reduced that the remainder,
as a matter of precaution, or for some trifling reason, abandoned it en
masse. This phase of pueblo life, more prominent in the olden days than
at present, but still extant, has not received the prominence it
deserves in the study of southwestern remains. Its effects can be seen
in almost every ruin; not all the villages of a group, nor even all the
parts of a village, were inhabited at the same time, and estimates of