mately
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 31/2 to 41/2 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 s