Casa Grande Ruin | Page 7

[Illustration: Pl. LIII: General View of Casa Grande.]
To the east and to the west are two large depressions, each about 5 feet
below the surrounding ground surface, evidently the places whence the

material for the construction of the mound was obtained. Yet the
amount of material removed from these excavations must have been
considerably in excess of that used in the construction of the mound,
and this excess was doubtless utilized in neighboring constructions,
since it is hardly to be supposed that it was carried away to any
considerable distance.
The purpose of this hollow mound, which is a fair type of many similar
structures found in this region, is not clear. Mr. Frank Hamilton
Cushing, while director of the Hemenway southwestern archeological
expedition, found a number of these structures and excavated some of
them. From remains thus found he concluded that they were
sun-temples, as he termed them, and that they were covered with a roof
made of coiled strands of grass, after a manner analogous to that in
which pueblo baskets are made. A somewhat similar class of structures
was found by the writer on the upper Rio Verde, but these were
probably thrashing floors. Possibly the structure under discussion was
for a similar purpose, yet its depth in proportion to its size was almost
too great for such use. The question must be left for determination if
possible by excavation.
In the southern central part of the map is shown another excavation,
covering a larger area than any of the others, of very irregular outline
and from 3 to 4 feet deep. It is apparently older than the others and
probably furnished the material for the house structures northeast and
southwest of it. Bordering the depression on the south there are some
low mounds, almost obliterated, which probably were the sites of other
house structures.
Scattered about the area shown on the map there are several small
depressions, usually more regular in outline than those described. The
best example is situated near the northeastern corner of the area. It is
situated in the point of a low promontory, is about 3 feet deep, almost
regularly oval in outline, and measures about 50 by 100 feet. A similar
depression less than 2 feet deep occurs near the northwest corner of the
area, and immediately south of the last there is another, more irregular
in outline, and nearly 3 feet deep. There are also some small

depressions in the immediate vicinity of the Casa Grande ruin and of
the mounds north of it.
With a single exception none of these depressions are so situated that
they could be used as reservoirs for the storage of water collected from
the surface, and the catchment area of the depressions is so small and
the rate of evaporation in this area so great that their use as reservoirs is
out of the question. It is probable that all of the smaller depressions
represent simply sites where building material was obtained. Possibly
the ground at these points furnished more suitable material than
elsewhere, and, if so, the builders may have taken the trouble to
transport it several hundred yards rather than follow the usual practice
of using material within a few feet of the site. This hypothesis would
explain the large size of the depressions, otherwise an anomalous
feature.
CASA GRANDE RUIN.
_State of Preservation._
The area occupied by the Casa Grande ruin is insignificant as compared
with that of the entire group, yet it has attracted the greater attention
because it comprises practically all the walls still standing. There is
only one small fragment of wall east of the main structure and another
south of it.
The ruin is especially interesting because it is the best preserved
example now remaining of a type of structure which, there is reason to
believe, was widely distributed throughout the Gila valley, and which,
so far as now known, is not found elsewhere. The conditions under
which pueblo architecture developed in the north were peculiar, and
stamped themselves indelibly on the house structures there found. Here
in the south there is a radical change in physical environment: even the
available building material was different, and while it is probable that a
systematic investigation of this field will show essentially the same
ideas that in the north are worked out in stone, here embodied in a
different material and doubtless somewhat modified to suit the changed
environment, yet any general conclusion based on the study of a single

ruin would be unsafe. In the present state of knowledge of this field it is
not advisable to attempt more than a detailed description, embodying,
however, a few inferences, applicable to this ruin only, which seem
well supported by the evidence obtained.
The Casa Grande ruin is located near the southwestern