the first roof level, there is a large, roughly circular opening or
window, 14 inches in diameter. This is shown in plate LX. It is smoothly
finished, and enlarges, slightly, outward.




CONCLUSIONS.


As before stated, any conclusions drawn from a study of the Casa Grande
itself, and not checked by examination of other similar or analogous
ruins, can not be considered as firmly established, yet they have a
suggestive value.

From the character of the remains it seems probable that the site of the
ruins here designated as the Casa Grande group was occupied a long time,
not as a whole, but piecemeal as it were, one part being occupied and
abandoned while some other part was being built up, and that this ebb
and flow of population through many generations reached its final period
in the occupation of the structure here termed the Casa Grande ruin. It
is probable that this structure did not exist at the time the site was
first occupied, and still more probable that all or nearly all the other
sites were abandoned for some time before the structure now called the
Casa Grande was erected. It is also probable that after the abandonment
of the Casa Grande the ground about it was still worked by its former
population, who temporarily occupied, during the horticultural season,
farming outlooks located near it.

[Illustration: Pl. LX: Circular Opening in North Room.]