Natural Science in Archaeology

270 11 Building, Monumental, and Statuary Materials
Mounded Earth. Earth materials have been used with minimal processing by
many societies, most notably on the North American continent. Cahokia in Illinois,
Grand Mound in Minnesota, and Poverty Point in Louisiana are probably the most
famous examples of monumental architecture built by the excavation, transportation,
and mounding of large quantities of earth. The mounds incorporated burials
and served as platforms for roofed houses or temples (Nabokov and Easton 1989).
On a smaller scale, earthen pit houses were popular with a number of indigenous
groups. For example, the Maidu and Miwok people of California excavated circular
pits in the earth and covered them with a roof of wood rafters and grass mats. The
excavated earth was spread over the top of the roof (Nabokov and Easton 1989).
These structures were easy to build, practical, and thermally efficient. Beyond the
excavation and movement of the soil, no further processing was required.
Rammed Earth. Called “pise”, or “terre pise” in some regions, other traditional
names for rammed earth compacted by pounding include “humra” (used for floors in
the Levant area of the Middle East), “tub” and “tabya” (Arabian Peninsula) (Michon
1990:100), and “tappa” (Sri Lanka) (Nandadeva 1990). Pise was also used in some
parts of western Europe, including the Rhone Valley of France (Dethier 1985). Sand
should comprise 50–75% of the earth mixture in order to prevent excessive shrinkage.
“The size range of the sand and coarse particles has no effect. In rammed earth
walls only a relatively small amount of clay is desirable and over 30% clay results in
rapid erosion” (Rapp and Aschenbrenner 1978). Recently, my colleagues and I have
used buried rammed earth (called hang-tu in China) city walls (Fig. 11.9) and building
platforms as a guide to ascertain when core drilling has located first and second
millennium BCE major sites. Shang and Zhou Dynasties used hang-tu extensively
for durable structures.
Fig. 11.9 Top of buried wall
of rammed earth (hang-tu in
Chinese), Shang Dynasty,
China