d perhaps do so to this
day.

The heavy tropical rains have to a great extent broken the sharpness of
the outline of these structures, and brought them more nearly to the
shape of real pyramids than they were originally; but, as we climbed up
their sides, we could trace the terraces without any difficulty, and
even flights of steps.

The pyramids consist of an outer casing of hewn stone, faced and
covered with smooth stucco, which has resisted the effects of time and
bad usage in a wonderful manner. Inside this casing were adobes,
stones, clay, and mortar, as one may see in places where the exterior
has been damaged, and by creeping into the small passage which leads
into the Temple of the Moon. Both pyramids are nearly covered with a
coating of debris, full of bits of obsidian arrows and knives, and
broken pottery. On the teocalli of the moon we found a number of recent
sea-shells, which mystified us extremely; and the only explanation we
could give of their presence there was that they might have been
brought up as offerings. A passage in Humboldt, which I met with long
after, seems to clear up the mystery. Speaking of the great teocalli of
the city of Mexico, he says, quoting an old description, that the Moon
had a little temple in the great courtyard, which was built of shells.
Those that we found may be the remains of a similar structure on the
top of the pyramid.

Prickly pears, aloes, and mesquite bushes have overgrown the pyramids
in all directions, as though they had been mere natural hills. In
Sicily one may see the lava fields of Etna planted with prickly pears:
in the ordinary course of things, it requires several centuries before
even the surface of this hard lava will disintegrate into soil; but the
roots of the cactus soon crack it, and a few years suffice to break it
up to a sufficient depth to allow of vineyards being planted upon it.
Here the same plant has in the same way affected the porous amygdaloid
with which the pyramids are faced, and has cut up the surface sadly;
but the vegetation which covers them will at any rate defend them from
the rains, and now centuries will make but little change in the
appearance of these remarkable buildings.

Near Nice there is a hill which gives a wonderfully correct idea of the
appearance of the terraced teocallis of Mexico, as they must have
looked before time effaced the sharpness of their lines. Where the
valley of the Paglione and that of St. Andre meet,