The Repair of Casa Grande Ruin, Arizona, in 1891 | Page 3

are strewn upon the ground in the vicinity.
The exterior walls rise to a height of from 20 to 25 feet above the
ground. This height accommodated two stories, but the top of the wall
is from 1 to 2 feet higher than the roof level of the second story. The
middle room or space was built up three stories high, and the walls are
still standing to a height of 28 to 30 feet above the ground level. The
tops of the walls, while rough and greatly eroded, are approximately
level. The exterior surface of the walls is rough, as shown in the
illustrations, but the interior walls of the rooms are finished with a
remarkable degree of smoothness, so much so that it has attracted the
attention of everyone who has visited the ruin. Plate CXV shows this
feature. At the ground level the exterior wall is from 3½ to 4½ feet
thick, and in one place over 5 feet thick. The interior walls are from 3
to 4 feet thick. At the tops the walls are about 2 feet thick. The building
was constructed by crude methods, thoroughly aboriginal in character,
and there is no uniformity in its measurements. The walls, even in the
same room, are not of even thickness; the floor joists were seldom in a

straight line, and measurements made at similar places (for example, at
the two ends of a room) seldom agree.
Casa Grande is often referred to as an adobe structure, but this use of
the term is misleading. Adobe construction consists of the use of
molded brick, dried in the sun, but not baked. The walls here are
composed of huge blocks of rammed earth, 3 to 5 feet long, 2 feet high
and 3 to 4 feet thick. These blocks were not molded and then laid in the
wall, but were manufactured in place.
Plate CXVI shows the character of these blocks. The material
employed was admirably suited for the purpose, being when dry almost
as hard as sandstone and nearly as durable. A building with walls of
this material would last indefinitely, provided a few slight repairs were
made at the conclusion of each rainy season. When abandoned,
however, sapping at the ground level would commence and would in
time bring down all the walls; yet in the two centuries which have
elapsed since Padre Kino's visit to this place--and Casa Grande was
then a ruin--there has been but little destruction from the elements, the
damage done by relic hunters during the last twenty years being, in fact,
much greater than that due to all causes in the preceding two centuries.
The building was well provided with doorways and other openings,
arranged in pairs, one above the other. There were doorways from each
room into every adjoining room, except that the rooms of the middle
tier were entered only from the east. Some of the openings were not
used, and were closed with blocks of solid masonry, built into them
long prior to the final abandonment of the structure.
CONDITION OF CASA GRANDE IN 1891
The south and east fronts of Casa Grande seem to have suffered,
particularly from the weather, and here rainstorms have probably
caused some of the damage. The outer faces of the walls are of the
same material as the wall mass, all the masonry being composed of
earth from the immediate site. In the construction of the walls this soil
was laid up in successive courses of varying thickness, whose limits
form clearly defined and approximately horizontal joints. The northeast

and southeast corners of the building have entirely fallen away, and low
mounds of their debris still show many knobs and lumps, parts of the
original wall mass.
The destruction of the walls was due mainly to undermining at the
ground level. The character of this undermining is shown in many of
the illustrations to this report, especially in plate CXVI, and its extent is
indicated on the accompanying ground plan (plate CXVII) by dotted
lines within the wall mass. Although the material of which the walls are
composed is very hard when dry, and capable of resisting the
destructive influences to which it has been subjected for a long time,
yet under certain conditions it becomes more yielding. The excessively
dry climate of this region, which in one respect has made the
preservation of the ruin possible, has also furnished, in its periodic
sandstorms, a most efficient agent of destruction. The amount of
moisture in the soil is so small as scarcely to be detected, but what
there is in the soil next to the walls is absorbed by the latter, rising
doubtless by capillary attraction to a height of a foot or more from the
ground. This portion of the wall being then