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Complexities of Strata
 Unfortunately,
unlike a layer cake, a stratum of a tell will not be uniform in
thickness or comprehensive in covering the site for several
reasons. Some sections may erode faster than others making the
stratum uneven. Also, the movement of water can move small (but
datable) materials away from their original setting. Ancient
peoples may have used one area more than another; thus, causing
strata to accumulate at different rates. Some parts of a tell
may go unoccupied while people live on other parts. This will
create strata that only partially cover the tell. There are other complexities
we must consider. Down grading, fills, pits, and foundational
trenches alter or destroy stratigraphy.
Grading Down. Just as people today
need level places to build a home, ancient people needed level
places too. There are two ways to level an area: grade down or
fill up. Both of these methods alter the natural development of
stratigraphy. Grading down is removing soil and debris from an
area. Removing soil and debris from its original context removes
a piece of the history of the site and creates an artificial
stratigraphy, that is, two layers that are incongruent in
sequence and time. The archaeologist can usually recognize
graded down areas only by comparing this stratigraphy with other
stratigraphic sections on the tell.
A Fill. A fill may seem harmless since
the soil is brought in from another location in order to raise
an area. However, just imagine what happens if the soil used for
the fill is removed from one place on the site (where people had
lived) and is relocated to another place. Let’s say an Iron II
Age person dug soil from an Early Bronze Age level that was
exposed at another place on the site and placed this soil (with
datable debris) on top of a Late Bronze level and then built an
Iron II Age house on it. The archaeologist would find the Iron
II house on top of Early Bronze debris, which is on top of Late
Bronze debris. Of course, the problem is that the Late Bronze
material should be on top of the Early Bronze material if the
stratification is natural, not the other way around. (I haven’t
mentioned the problem the archaeologist will have when he/she
tries to determine the stratigraphy where the Early Bronze
material was removed.) Now the archaeologist has the task of
determining why the strata are out of chronological order.
 Pits. Another occupational feature destructive to
stratigraphy is pits. Defined simply, pits are holes dug into
the ground. {Photo 1981 near here.} These holes, when initially
dug, destroy earlier stratigraphic layers and create new ones.
People dug pits for many reasons. Pits functioned as storage
bins, grain silos, trash dumps, latrines, cisterns, tombs, etc.
Archaeologists treat a pit as a separate stratum, with the
material in the pit used to help date when the pit was in use. [
Photo]
 Some people dug pits
looking for previously used building materials. If building
materials are reused, this creates an additional problem: styles
from one period being used in walls of another period. Not only
does the digging destroy stratigraphy, but also the reuse of
materials can confuse the dating of structures. Pits can have natural
causes. Roots from trees growing on the site can create pits
through their growth and decay. Yet tree roots are generally
small and are easily recognized. The more destructive natural
cause for a pit is a rodent hole. Rodents make larger holes than
tree roots and rodents tend to carry foreign material into their
holes for their nests. While excavating at Tell Halif in Israel,
I saw where a modern rodent had dug a hole down to the Iron II
strata and created a nest there. Inside this nest we found
plastic, a very modern material!! Fortunately, we had been
careful in our excavation and had recognized the rodent’s
intrusion before we found the plastic.
Foundation Trench. A foundation trench
is another element destructive to stratigraphy. As one would
build a home today, ancient people dug trenches to lay a
foundation for a new building. Foundation trenches disrupt
stratigraphy, like pits, in that they intrude and destroy
previous levels of occupation and introduce a new one. However,
the material found in a trench next to a wall can help date the
wall itself.
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