110 CHAPTER 5 | Field Methods in Archaeology and Paleoanthropology
and metal are more resistant to decay than organic ones
such as wood and bone. Sometimes the anthropologist
discovers an assemblage—a collection of artifacts—made
of durable inorganic materials, such as stone tools, and
traces of organic ones long since decomposed, such as
woodwork (Figure 5.3), textiles, or food.
Climate, local geologic conditions, and cultural practices
also play a role in the state of preservation. For example, our
knowledge of ancient Egyptian culture stems not only from
their burial practices but from the effects of climate and soil
on preservation. The ancient Egyptians believed that eternal
life could be achieved only if the dead person were buried
with his or her worldly possessions. Hence, their tombs are
usually filled with a wealth of artifacts, including the skel-
etons of other humans owned by dynastic rulers.
Under favorable climatic conditions, even the most per-
ishable objects may survive over vast periods of time. The
earliest Egyptian burials, consisting of shallow pits in the
sand with bodies buried long before mummification was
practiced, often yield well-preserved corpses. Their preser-
vation can only be the result of rapid desiccation, or com-
plete drying out, in the warm desert climate. The elaborate
tombs of the rulers of dynastic Egypt often contain wooden
furniture, textiles, flowers, and written scrolls on paper made
from papyrus reeds, barely touched by time, seemingly as
fresh looking as they were when deposited in the tombs as
long as 5,000 years ago—a consequence of the region’s arid
climatic conditions. Of course, the ancient Egyptian burial
practices selectively preserved more information about the
elite members of society than the average individual.
The dryness of certain caves is also a factor in the
preservation of coprolites, the scientific term for fossil-
ized human or animal feces. Coprolites provide informa-
tion on prehistoric diet and health. From the analysis
of elements preserved in coprolites such as seeds, in-
sect skeletons, and tiny bones from fish or amphibians,
archaeologists and paleoanthropologists can directly
determine diets from the past. This information, in turn,Hearth
Pottery
BricksSkullStonework
Bone
More
ancient
More
recentFigure 5.2 Some sites are stratified, in that archaeological
remains lie in layers stacked one on top of the other; older
layers are lower down, and more recent layers are on top.
Geologic processes will result in strata of different depths in
different places. Careful mapping of each stratum using the
grid system is essential for interpretation of the site.
and tissue paper to prevent cracking and damage during
further excavation and handling.
Both the fossil and the earth immediately surround-
ing it, or the matrix, are prepared for removal as a single
block. The bones and matrix are cut out of the earth (but
not removed), and more shellac is applied to the entire
block to harden it. The bones are covered with burlap
bandages dipped in plaster. Then the block is enclosed in
more plaster and burlap bandages, perhaps splinted with
tree branches and allowed to dry overnight. After it has
hardened, the entire block is carefully removed from the
earth, ready for packing and transport to a laboratory. Be-
fore leaving the discovery area, the investigator makes a
thorough sketch map of the terrain and pinpoints the find
on geologic maps to aid future investigators.
State of Preservation of
Archaeological and Fossil Evidence
The results of an excavation depend greatly on the con-
dition of the remains. Inorganic materials such as stone
Figure 5.3 Although the wooden posts of a house may have long since decayed, their positions may
still be marked by discoloration of the soil. The plan shown on the left—of an ancient post-hole pattern
and depression at Snaketown, Arizona—permits the hypothetical house reconstruction on the right.
coprolites Preserved fecal material providing evidence of the
diet and health of past organisms.