contours.

Within the area shown on the map there are a large number of mounds,
more or less leveled by long-continued exposure to the elements. Some
appear to be quite old, others represent buildings which were standing
within the historic period, and many interesting features are presented
which can not even be alluded to here.

Casa Grande proper was one of the smallest of the house clusters, but it
is unique in that the walls are still standing to a height of more than
25 feet. While fragments of standing wall are not uncommon, either in
the area mentioned or in the valleys of Gala and Salt rivers generally,
no other example exists, so far as known, so well preserved as the one
under consideration.

For miles around Casa Grande the ground surface is so flat that from the
summit of the walls an immense stretch of country is brought under view
in every direction. In the whole southwest, where there are thousands of
ruins, many of which represent villages located with especial reference
to outlook, there are few, if any, so well situated as this.

A ground plan of the ruin is shown in plate CXII and a general view in
plate CXIV. The area covered and inclosed by standing walls is about 43
by 59 feet, but the building is not exactly rectangular, nor do its
sides exactly face the cardinal points, notwithstanding many published
statements to that effect. The building comprised three central rooms,
each approximately 10 by 24 feet, arranged side by side with the longer
axes north and south, and two other rooms, each about 9 by 35 feet,
occupying, respectively, the northern and southern ends of the building,
and arranged transversely across the ends of the central rooms, the
longer axes running east and west. Excepting the central tier of rooms,
which was three stories high, all the walls rose to a height of two
stories above the ground. The northeastern and southeastern corners of
the structure have fallen, and large blocks of the material of which
they were composed 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 approxi