DISCOVERIES AT PLATA1A.
We now turn toward the east and follow the upper cross-wall. This
is by far the best built of all the walls; it is of the third period, and
is in places in a very good state of preservation. It runs for 407 m.
toward the southeast in a line almost straight, at one point making
a bend of less than 2° and at another of 10°, and there turns to
the northeast and runs toward Church No. V. The wall is every-
where 3.30 m. wide, both faces carefully finished (the outer one, that
toward the south, the better) and the space between filled with rubble
of earth and stones. The present height of the ruins varies greatly ;
at places they barely appear above ground, while at their highest
point, the third tower from the west end, the structure is 3.80 m. above
ground.* Along the outer, i. e., the southern, side of the wall there
are remains of eight towers of rectangular plan, measuring 6.70 m.
in length (i. e., along the wall) and 5 m. in breadth. The variations
are only a few centimetres either way from these averages. The towers
are distant from one another 42.50 m., and form an integral part of
the wall, not added to the outer face but built at the same time and
continuously with it. The best-preserved example is the tower above
mentioned, and it offers a few points of interest. The main courses
rest on a foundation-wall, projecting 10 cm. beyond them, the blocks
of which measure only 40 cm. high instead of 1 m., as in the courses
above. This foundation is carefully worked with vertical or very
slightly oblique joints, and furrowed facing. In this tower at present
three courses of the foundation are above ground, while a similar
foundation runs beneath the wall proper, though not visible at present,
except at one or two points, owing to the accumulation of earth.
The corners of the towers present a striking peculiarity. The rough,
bulging sides have been cut in from both sides, so as to leave a sharp
right-angled ridge along the vertical edge, finished smooth and clean.
This right-angled ridge, which measures 10 cm. on each side, is carried
along the whole angle of the tower and is continued in the foundation.
It occurs in every tower on all the walls of the first three periods, its
use in this upper cross-wall being probably copied from the older M alls.
The towers, as far as can be judged, were solid, filled up within, like
the walls. Another peculiarity of the upper cross-wall (also occur-
ing once in the extreme south wall) is that there are several "plat-
forms," as they have been called, built on the inside of the wall.
These are thickenings of the wall, about 10 m. long and 1 m. thick,
and were probably buttresses to strengthen the main wall, though too
* See I'late xvn.