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MWAC
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Hopewell
Archeology:
The Newsletter of Hopewell Archeology
in the Ohio River Valley
Volume 6, Number 1, September 2004
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6. Earthwork Construction and the Organization
of Hopewell Society
By Mark
J. Lynott, Midwest Archeological Center
The mounds and geometric enclosures
of southern Ohio have fascinated scholars
for two centuries, but many of the questions
that sparked the interest of 19th-century
antiquarians have yet to be fully addressed
today. Contemporary scholars are proposing
new and interesting interpretations about
these impressive sites, but the sites themselves
are disappearing. None of the great geometric
enclosures has survived unscathed, and many
of them can only be studied now by examining
old aerial photographs or reading historic
accounts. The need for field investigation
of the remaining sites has never been greater.
Archaeological study of geometric enclosures
in southern Ohio has been limited, with
most work being focused on mounds associated
with
the enclosures. The large size of these
sites has certainly served to deter
excavations,
and most studies have been limited to
one or two summers of excavation. While
these
studies have generated useful information
about some aspect of individual earthworks,
none have generated a holistic view of
any large geometric enclosure. Fortunately,
geophysical
survey instruments make it possible to
map large areas; these data can be
used to plan
strategic excavations. The utility of
this approach is illustrated by recent
work on
the rectangular enclosure at the Hopeton
Earthworks, Ross County, Ohio.
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Hopeton Earthworks is located north of
Chillicothe. It was described by Squier and
Davis as being a rectangle with an attached
circle (Figure 1). The earthwork also has
two smaller circles that were integrated
into the north side of the rectangle and
a pair of parallel walls that extend from
the northwest corner of the rectangle 2400
feet to the southwest. The walls of the two
larger enclosures were formed by a series
of wall segments. Each was estimated to enclose
20 acres. The walls of the rectangular work
were of monumental size, twelve feet high
by fifty feet at their bases, and lacking
a ditch on either side.
Geophysical Survey and Research Design
More than 150 years of cultivation have
greatly reduced the walls of this enclosure,
to
the point where they are barely visible
to the untrained eye. In 2001, the National
Park Service initiated geophysical survey
at Hopeton to determine if geophysical
equipment could be useful in evaluating
the subsurface composition of mounds
and earthen walls. Reports in-progress
elaborate
on the geophysical studies; it should
be noted here, however, that the efforts
of
John Weymouth, Bruce Bevan, Rinita Dalan,
and Rolfe Mandel are producing exceptionally
useful data.
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Figure 1. Ephraim Squier and Edwin
Davis mapped the major earthwork features
of the Hopeton site in 1846 and published
their findings in a classic volume
that illustrates and describes many
nowdestroyed
Hopewell earthworks (Squier and Davis
1848:51–52, Plate 17). |
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on image to enlarge |
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Figure 2. The locations of
Trenches 1 through 4. These trenches
were placed to give representative
cross section information for the
main enclosure wall of the large
square.
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The bulk of our survey efforts have
relied upon a Geometrics G858 cesium
gradiometer. The most important accomplishment
was the discovery that the wall segments
of the rectangular enclosure are distinctly
visible in the magnetic survey data (Figure
2). The sharp boundaries on the interior
and exterior of the wall segments are
in marked contrast to the topography
of these features, which is very gradual
due to years of annual cultivation. The
sharp magnetic contrast between the core
of the wall and the surrounding soils
of the landform suggested that the wall
must have been constructed from soils
that differ markedly from the natural
soils of the alluvial terrace. |
| In an effort to determine
how much of the original wall was preserved
at Hopeton, the geophysical survey data
were used to select four locations around
the rectangular enclosure for test excavations.
In 1996, Bret Ruby excavated a 1-m-wide
trench across a wall segment at the
northwest corner of the rectangular
enclosure. Aerial photographs indicate
this section of wall was preserved
in a fence-row since at least 1938.
The 1996 trench revealed that three
different soil deposits were present
in the wall, each representing a different
stage of construction (Ruby 1997:3–4).
Using this information, we developed
a plan for testing other wall segments
to determine whether we might be able
to learn how and when they were built.
Trench Excavation Results
Field studies of the walls that form
the rectangular enclosure were conducted
from 2001 to 2003. Using the geophysical
survey data to evaluate the potential
preservation of the wall segments,
we selected four locations in four
different wall segments for trenching
(Figure 2). Each trench was 1.5 m wide
and varied in length from 41 to 50
m. Trench 1 was in the central segment
of the southern wall of the enclosure.
Trenches 2 and 3 were excavated through
wall segments forming the western wall,
and Trench 4 was excavated across the
only curved wall segment that forms
the northeast corner of the enclosure.
Examination of each of the trenches
revealed that although there were some
general similarities in the methods
and materials used to build the wall
segments, each wall segment was different.
In each wall segment, construction
was started with removal of topsoil
to expose the subsoil. Two different
subsoils are present on this landform.
Yellow silt loam was exposed at the
bases of Trenches 1, 2, and 3, and
red sandy loam was exposed at the base
of Trench 4. In each of the wall segments,
the builders performed rituals that
involved burning. These activities
left small burned soil features with
charred materials often at the interface
of two different construction stages.
Unfortunately, due to degradation from
years of agriculture, we are only able
to observe the first stages of wall
construction that form the base of
the individual wall segments. |
| The base
of the wall segment exposed by Trench
1 was formed by piling up yellow
silt loam similar to the subsoil,
and then covering the top and outside
of the yellow soil with a red sandy
loam (Figure 3). In Trenches 2 and
3, a dark gray-brown silt loam was
piled on the yellow subsoil to form
the base of the wall. Then yellow
or yellow-brown soil was piled on
the east or inside of this dark material,
and red or red-brown soil was placed
on the west or outside of the wall
segments. The configuration and colors
of the materials used in these two
segments are quite different, but
the pattern of construction as just
described is similar. |
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on image to enlarge |
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Figure 3. The west wall profile
in Trench 1 showing distinct
soil colors; Profile 3, 2852N,
June 2001. The base of the
wall was created by piling
up yellow silt loam similar
to the subsoil. The top and
outside surfaces were then
covered with red sandy loam. |
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The contacts between the
soil layers exposed in all three of these
wall segments were generally distinct,
suggesting that little time elapsed between
the deposition of the different materials.
To determine if this observation was
valid, Rolfe Mandel conducted micromorphological
analysis of sediments from Trench 1.
This analysis indicates that no evidence
of weathering or soil formation is present,
and construction of the wall segment
probably occurred in a few years or less
(Lynott and Weymouth 2002:5).
The situation in Trench 4 is quite
different from what was observed in
the other trenches. Wall construction
was initiated by stripping the topsoil
and exposing the red sandy loam subsoil.
The subsoil was then covered by a layer
of dark gray loam with lenses of fine
gravel. |
click
on image to enlarge |
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Figure 4. Detail in the profile
of Trench 4. Small lenses of
different soil materials appear
to represent basket loads. As
a group, these lenses form a
complex boundary between the
two major soil units. |
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Dark gray loam was then deposited
on the dark base to form the core
of the wall segment. Red sandy loam
was then piled on the south or inside
of the dark core, and the contact
between these two layers exhibits
a sharp boundary. Gray-brown loam
was deposited on the north side of
the dark core, but the boundary between
these two materials is not sharp.
Numerous small lenses of different
soil materials, which appear to represent
basket loads, form a complex boundary
between the two soil units (Figure
4). |
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| Construction Methods and Episodes
One of the goals of this study is to determine
when the walls of the rectangular enclosure
were built. Fortunately, the people who
built the wall segments conducted rituals
that included burning wood and other materials
in association with the various stages
of wall construction. Four radiocarbon
dates from features in Trenches 1, 2 and
3, plus two other radiocarbon dates obtained
by Bret Ruby from his 1996 trench suggest
these wall segments were probably built
between AD 150 and AD 250.
Two radiocarbon dates were obtained from
features in Trench 4, and they are both 800
years more recent than the dates obtained
from the other trenches. Since one of the
samples was taken from a feature at the very
base of the wall segment, it seems unlikely
that these represent intrusive episodes that
postdate construction of the wall segment.
When these dates are considered in association
with the unusual construction methods recorded
in Trench 4, it seems likely that this wall
segment was either built many centuries after
the other wall segments, or it was modified
or repaired at this later time.
The work on the rectangular enclosure at
Hopeton demonstrates that variation in wall
construction methods, and even the age of
wall construction, might be significant within
individual earthworks. Understanding the
methods and materials used to build these
walls is important, because the amount of
energy that was invested is a reflection
of the values, labor force, and social organization
of the people who built the enclosure.
Study of the materials used to construct
the walls at Hopeton indicates that all of
the soil and gravel selected for this purpose
was available on the landform where the site
is located. The massive amounts of soil used
to build the walls were quarried with hand
tools and carried in baskets, and vast amounts
of soil were moved all across the site. This
substantial earthmoving resulted in the creation
of a cultural landscape that was probably
cleared of vegetation to facilitate gathering
and moving soil around the site.
Rather than simply scooping up soil and piling
it into an earthen wall, the wall segments
at Hopeton were built with carefully selected
soils. The entire process began by removing
all topsoil from the area where a wall segment
was to be built. The action of exposing the
yellow or red subsoil certainly provided
a very stable foundation for the wall segment,
but it also probably was related to the Hopewell
people’s efforts to manage the spirit
world. In the wall segments we examined on
the south and west sides of the Hopeton rectangular
enclosure, the wall builders always placed
red soil on the side of the wall that would
be viewed from outside the enclosure. Yellow
soils were always placed on the side of the
wall that would be viewed from inside the
enclosure. The contacts between the different
soils used to build these wall segments are
sharp and clear, and it is obvious that the
selection of soil and its placement in the
wall was carefully engineered. These wall
segments were all built about AD 200.
The curving wall segment that forms the northeast
corner of this enclosure is quite different.
In this area, the topsoil was removed to
expose red subsoil, and this wall segment
is constructed primarily of red sandy loam
plus two different shades of gray loam. There
are large homogenous deposits of these materials
in the wall, but the contacts between the
different soil materials are frequently marked
by basket-loading. In this instance, red
soil was placed to be visible from inside
the rectangular enclosure and gray loam would
have been visible from outside the enclosure.
Of course, as time went by, and soil formed
on the earthen walls, the wall colors would
have become less noticeable. The variation
we have noted in the color placement and
construction methods between these wall segments
might be related to some intended differences
in function. However, the radiocarbon dates
from the curved wall segment suggest that
the curved wall segment was completed about
800 years after the other wall segments were
complete. |
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Conclusions
As archaeologists and geophysicists continue
to study the relationship between geophysical
data and the archaeological record,
it is apparent that this line of research
will provide a more accurate depiction
of the original placement and size
of the wall segments than can be obtained
from either current topographic maps
or 19th-century historic maps (Figure
5). Recent interpretations suggest
the placement of gateways at Hopeton
and other Hopewell enclosures were planned
to view solar and lunar events. Evaluation
of these hypotheses can be accurately
evaluated through large-scale geophysical
mapping of these sites. Geophysical survey
also provides an efficient and effective
way to develop a holistic view of the
archaeological record of these giant
earthen monuments. This can be a particularly
effective way to view large sites when
done in concert with systematic surface
collections and strategic testing efforts. |
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on image to enlarge |
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Figure 5. Magnetic survey coverage
through 2003 at Hopeton Earthworks.
Data from three field seasons are
compiled; the resolution is 1 m by
1m. |
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The timing of the introduction of these
new technologies to the study of Ohio Hopewell
is critical. Earthworks and mounds were once
plentiful across all of southern Ohio. Urban
growth, agriculture, and other development
activities have damaged or destroyed nearly
every single earthen monument in this region.
The forces impacting the archaeological record
continue to escalate as population grows,
cities expand, and agriculture continues.
A number of important sites have been purchased
and preserved. Unfortunately, now that methods
and technologies that permit effective study
of these large sites are becoming available,
the vast majority of large Ohio Hopewell
sites are being erased from the cultural
landscape. Increased efforts to preserve
sites for future study are certainly needed,
but more large-scale archaeological studies
of these great places are also needed before
they are lost forever.
Note: this article is a slightly modified
version of a paper presented at the 69th
Annual Meeting of the Society for American
Archaeology, Montreal, Canada, April 4, 2004.
References Cited
Lynott, Mark J., and John Weymouth
2002 Preliminary Report, 2001 Investigations,
Hopeton Earthworks. Hopewell Archeology 5(1):1–7.
Ruby, Bret J.
1997 Current Research at Hopewell Culture
National Historical Park. Hopewell
Archeology 2(2):1–6.
Squier, Ephraim G., and Edwin H.
Davis
1848 Ancient Monuments of the Mississippi
Valley. Smithsonian Contributions
to Knowledge, Volume 1. Smithsonian
Institution, Washington, D.C. The
Smithsonian
Institution reprinted this volume in 1998 as the 150th Anniversary Reissue
Edition, which includes a special
Introduction by David J. Meltzer.
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