they applied with mortar to the surface of brick-faced walls of
poured concrete, producing an elegant appearance that mim-
icked worked blocks of marble, but at greater speed and con-
siderably less expense. Despite this economy of stone, there
seems to have been a fear that the supply would eventually
be exhausted, which probably prompted the fantastic stories
in Pliny and others about marble quarries in which the stone
was magically regenerated.
Salt played the same important role as a preserver of food
for the Romans as it did for the Greeks. Th e cit y of Rome itself
was blessed almost from its foundation with control of the
natural salt beds at the mouth of the Tiber River near Ostia,
which gave it an economic advantage over its Latin neighbors.
Th e Latin adjective salarius (“pertaining to salt”) was applied
not only to the road that led from these salt beds to Rome but
also to part of the payment to soldiers for their subsistence
(our word salary). Rock salt was mined for export in some
locations (like Cappadocia in central Turkey), but evaporated
sea salt was the most important source: terra-cotta salt pots
and lead saltpans, in which the brine was heated to drive off
the seawater, have been found throughout the Roman Em-
pire, from Egypt and the eastern port cities of Caesarea and
Ephesus to towns in remote Britain. Th e most useful descrip-
tion of techniques used to extract salt is given by Pliny, who
notes in his Natural History that fresh water (from rain or riv-
ers) was oft en added to seawater before evaporation, to “make
the salt sweet.”
THE AMERICAS
BY KEITH JORDAN
Stone quarrying in the New World dates back to the time of
the fi rst human inhabitants during the last ice age, 12,000 or
more years ago. Since stone was the primary material used to
make tools and weapons throughout the Americas right up to
the 16th century c.e., numerous quarry sites have survived to
be excavated by modern archaeologists. In most cases stone
hammers were used to extract fl int, chert, and other useful
stones from surface outcrops. In southern New England, for
example, Native Americans during the Terminal Archaic
into the Early Woodland periods (ca. 1500–700 b.c.e.) ex-
tensively worked deposits of steatite (soapstone), from which
they carved cooking vessels. Th ey broke up the surrounding
rock with handheld hammer stones and used pointed stones
to further reduce detached pieces of stone. Stone spades were
employed to clear away the fragments.
Th e oldest-known and longest-lasting large-scale mining
operations in the ancient New World were the copper mines
of the Keweenaw Peninsula and Isle Royale, Michigan, which
were worked from the Late Archaic Period (ca. 3000 b.c.e.)
to the time of European invasion in the 17th century c.e. Al-
though Native North Americans did not smelt or cast copper,
they produced implements and ornaments by cold hammer-
ing nuggets of pure copper or by hand working heated mate-
rial (a process called annealing). Th e copper extracted from
these Lake Superior mines was traded across the eastern half
of North America and was the source for most of the cop-
per ornaments and ritual objects found in the Adena and
Hopewell burial mounds. While local sources in the Appala-
chian Mountains may account for some of the copper found
in southeastern archaeological sites, no evidence of prehis-
toric mining has yet turned up in this region.
Native American miners in Michigan dug trenches and
pits to reach deposits of copper. Th ey used fi ve- to 40-pound
stone hammers, or mauls, to break up the surrounding rock
and smaller hammers to extract lumps of copper from de-
tached chunks of stone. Some of these hammers were at-
tached to wooden haft s or swung on thongs, while others were
probably held in the miner’s hand. Th e diggers also may have
employed a process of alternatively setting fi res over bedrock
and then dousing the area with water to shatter the stone for
easier digging; they then used wooden spades or scoops to
dig out the loosened pieces of copper. Stone or copper wedges
may have been inserted to pry chunks of metal away from the
surrounding rock. In some locales the miners needed to sink
their shaft s as deep as 50 feet to reach the ore. Th ey presum-
ably removed the usable metal in baskets or skin bags, and
baskets and wooden buckets served to bail out the frequently
fl ooded pits. Some excavations were lined with wood or stone
blocks to prevent cave-ins.
By 1500 b.c.e. Olmec workers were quarrying basalt, a
volcanic stone, in the Tuxtla Mountains of the modern Mexi-
can state of Veracruz and transporting huge blocks to politi-
cal and religious centers some 60 miles south to be worked
into monuments for royalty. Th e stone was detached by bash-
ing it with smaller stones—a laborious eff ort in itself. Tons of
basalt were then transported to the Olmec sites through 60
miles of jungle, perhaps by fl oating the material on log raft s
down local rivers and then rolling it on logs once on land—a
truly astonishing achievement for this ancient workforce.
In addition to material for monumental construction, the
Olmec and their contemporaries quarried and traded many
other minerals. Obsidian, a volcanic glass used for making
extremely sharp blades and spear points, came from surface
outcrops in the Basin of Mexico and in southern Guatemala.
Th e source of the blue-green jade favored by the Olmec for
ornaments and ceremonial objects was once a mystery, but
accidental discoveries now indicate that it is found as eas-
ily removed cobbles or boulders along the Motagua River in
Guatemala.
Th e Maya used the local limestone underlying the for-
ests of Yucatán and Guatemala for construction at least as far
back as 600 b.c.e. Limestone bedrock was broken up using
stone hammers and chisels and by setting fi res. Fire was also
used to reduce limestone to powder useful in the manufac-
ture of stucco and plaster to decorate building facades and
serve as mortar.
In the early centuries c.e. demands generated by the
central Mexican metropolis of Teotihuacán and partners in
its far-fl ung trading network seem to have catalyzed the de-750 mining, quarrying, and salt making: The Americas