or a people suddenly scattered as the
Toltecs were--so suddenly as to leave temples half finished, and blocks
of stone half hewn--would have no further use for copper tools; and
hence the raw material would no longer have a value. In the abandoned
quarries near Mitla, amid fragments of pillars and architraves and
half-finished blocks of granite, copper axes, chisels, and wedges were
found in abundance; but the same inordinate love of money that prompted
adventurers to flock to Chiriqui, a few years since, to rob the ancient
burying-grounds of their golden idols, induced others to search the old
quarries and mines of Mexico and Central America, and take from them any
relics that were intrinsically valuable.

In Mexico, the mounds were built so that their summits were visible from
every portion of the surrounding city, in order that the inhabitants
might continually have in view the sacred fires that were ever kept
burning on each side of the sacrificial altar. The same is strikingly
true of the mounds at the West; for they are invariably placed so that
their summits occupy a commanding position,--a circumstance that has
induced many to suppose them to have been built for military purposes,
and to have served as watch-towers. But when we reflect that the attacks
of savage or half-civilized peoples are usually made in the night-time,
we shall hardly suppose these structures were raised for any such
purpose. The Pyramid of Cholula is composed of alternate layers of brick
and clay, or possibly of burnt and unburnt brick; and others in Mexico
are built of unburnt brick. Many of the mounds in the West are of
clay,--perhaps of unburnt brick,--in situations where clay is not so
abundant as other earths.

I recollect visiting Circleville, Ohio, when it was really a
_Circle_-ville. An octagonal court-house stood upon an ancient mound,
and the dwellings and stores were built upon an ancient circular wall of
earth that encompassed an area around the mound. South of this circular
inclosure, and joining it, was a square inclosure of several acres,
surrounded by a wall about ten feet high. What is remarkable, this
square wall--and we presume the same is true also of the mound and
circular wall--was built of clay, perhaps of unburnt brick, that must
have been transported a considerable distance; for no clay exists upon
that alluvial bottom, and the nearest point where it is found is three
fourths of a mile distant, across a considerabl