INTRODUCTION TO ARCHAEOLOGY Nancy White - Touro Institute

What other technological devices must modern
archaeologists use? Lately we must have a Global
Positioning System (GPS) unit, which reads signals
bouncing off several satellites to give exact locations
in latitude/longitude or other coordinates. We also
want to utilize Geographic Information Systems (GIS),
which are simply computerized ways of making maps
of different features that can be overlain to show
relationships of natural and cultural features through
time.
Once the site
is found, how do you know what part of it to dig? Site
survey and mapping can be done at several levels,
from a rough sketch using a compass and pacing
distances to formal mapping with a surveyor’s transit,
electronic station, or other device. A typical local site
here is a scatter of artifacts on the surface, but there
may be a mound, concentrations of artifacts, a stream
or hill, modern features such as roads, that all need to
go on a base map. We often set up a site grid in
uniformly sized squares so that everything can be
precisely mapped in plan view and later in three
dimensions. There are good examples in your book
(pp. 91-93; show other examples of site maps).
After getting control of horizontal space, how does
archaeology tackle vertical space? Excavation must be
done with an understanding of stratigraphy, the
stratification or vertical positioning of soils and other
materials in layers or strata. The law of superposition
dictates that the earliest strata are usually the deepest
(but there are exceptions in disturbed strata such as
riverbank flood deposits or deliberately constructed
mounds—see diagrams in book, pp. 96-97). It is
important to be able to recognize strata deposited by
natural geological processes and cultural processes or
both, but it may be difficult. Since we want vertical as
well as horizontal control, we ideally want to excavate one stratum at a time without mixing
them. This is not always possible if color, texture, and content differences are hard to see. In
such cases we can still maintain some control by digging in arbitrary levels of a standard
thickness, such as 10 cm at a time. Sometimes we might dig in smaller arbitrary levels of 5 cm
within a thicker cultural stratum, for even tighter control. Or, for a really slow but careful dig,
recording each and every find in three dimensions can be done too. A formal excavation unit can
be as small as a meter square or as large as many meters. We usually dig in squares to be able to
see a clean view of vertical layering. We usually use metrics since they are easier and more