aracter. There is a suggestion that the opening was only 2 feet high,
and there were probably three tiers of lintels above the opening, the
top of which was 21/2 feet below the roof beams, but the evidence is not
so clear as in the other instances.

In the middle of the western wall, at a height of 5 feet 8 inches above
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.]

The methods employed in the construction of the buildings of the Casa
Grande were thoroughly aboriginal and characteristically rude in
application. A fair degree of adaptability to purpose and environment is
seen, indicating that the Casa Grande was one, and not the first,
building of a series constructed by the people who erected it and by
their ancestors, but the degree of skill exhibited and amount of
ingenuity shown in overcoming difficulties do not compare with that
found in many northern ruins. As architects, the inhabitants of the Casa
Grande did not occupy the first rank among pueblo-builders.

It is probable that the Casa Grande ruin as we see it today shows very
nearly the full height of the structure as it stood when it was
ab