estward, is quite wide on top, wide enough to
accommodate a single row of rooms of the same width as those of the
ruin, and it is hardly reasonable to suppose that a wall would be built
10 or 12 feet wide when one of 4 feet would serve every purpose to which
it could possibly be put. Furthermore, the supposition of an inclosing
wall does not leave any reasonable explanation of the transverse ridges
above mentioned, nor of the long ridge which runs southward from the
southeastern corner of the ruin.

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
now 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
now 28 to 30 feet above the ground level. The tops of the walls, while
rough and much 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 as to attract the attention of everyone who has visited the
ruin. Mange, who saw the ruin with Padre Font in 1697, says the walls
shine like Puebla pottery, and they still retain this finish wherever
the surface has not cracked off. This fine finish is shown in a number
of illustrations herewith. The walls are not of even thickness. At the
ground level the exterior wall is from 31/2 to 41/2 feet thick, and in one
place at the southern end of the eastern wall, is a trifle over 5 feet
thick. The interior walls are from 3 to 4 feet thick at base. At the top
the walls are reduced to about 2 feet thick, partly by setbacks or steps
at the floor levels, partly by exterior batter, the interior wall
surface being approximately vertical. Some writers, noting the
inclination of the outer wall surface, and not seeing the interior, have
inferred that the walls leaned considerably away from the perpendicular.
This inference has been strengthened, in some cases, by an examination
of the interior, for the inner wall surface, while finely finished, is
not by any means a plane surface, being generally concave in each room;
yet a line drawn from floor level to floor level would be very nearly
vertical. 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 t