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Ohio's Great Serpent Mound Surveyed

  • Ohio Valley Archaeology, Inc.


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ISAP News 32 Page 1
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elcome to the 32nd issue of ISAP
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who have found the time to
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you will find it an enjoyable read.
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reviews of the CAA ISAP roundtable
discussion and the First International
Conference on Virtual Archaeology - making
this issue a good place to catch up on
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surveys from Ohio, Cyprus and Egypt. We
also have the press release of Geoscan’s new
RM85 resistance meter!
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Editor’s Note
Robert Fry
Important Notices
Issue 32: August 2012
Editor’s Note 1
Robert Fry
Computer Applications in Archaeology
(CAA): ISAP Roundtable 2
Kayt Armstrong, Chris Gaffney
Ohio’s Great Serpent Mound Surveyed 6
Jarrod Burks
Large-scale Archaeogeophysical Surveys at
the Late Bronze Age Settlements at Kalavasos-
Ayios Dhimitrios and Maroni-Vournes/-Tsaroukkas
in Cyprus 8
Michael “Bodhi” Roger, Kevin Fisher, Jeff Leon and Sturt
Press Release: RM85 Resistance Meter is now
available from Geoscan Research! 12
Roger Walker
The First International Conference on Virtual
Archaeology 13
Daria Hookk and Armin Schmidt
New Geophysical Survey of the City and Necropolis
at Antinoupolis, Middle Egypt 15
Kristian Strutt, James Heidel, Angus Graham
Conferences, Workshops and Seminars 18
Journal Notification 19
Academic Courses 20
ISAP News 32 Page 6
erpent Mound is perhaps one of the most
iconic prehistoric Native American sites in
North America (Figure 1). While images of
this ca. 415 m long, serpent-shaped
embankment appear in countless books, very little
archaeological work has occurred at the site since
Frederick Ward Putnam coordinated its purchase
and reconstruction in the late 1880s (cf. Fletcher et
al. 1996; Putnam 1889/1890). In 2011 a consortium
of archaeologists from Ohio and Indiana pooled
their resources and expertise to take a much needed
closer look at the site. Because of the site’s
importance and high visitation, our initial research
permit only allowed for geophysical survey and
limited coring with a GeoProbe 54TR. My role as
part of the team was to conduct a magnetic gradient
survey and follow up with secondary investigations
dditional geophysics and excavations) of any
magnetic anomalies of interest.
Figure reated
y the author, DEM provided by William F. Romain, data
near the tail are likely related to a nineteenth-
1 LiDAR image of Serpent Mound (image c
bfrom Ohio Department of Transportation).
Figure 2 shows the results of the magnetic gradient
survey using a Geoscan Research FM256 fluxgate
gradiometer (8 readings per meter along transects
spaced 50 cm), with data processing through
Geoplot 3.0. As expected, the Serpent itself was
easily detected, which is no doubt a factor of its
height (2-5 ft) and the fact that a significant portion
of its fill was made with topsoil scraped off the
surrounding hilltop (both in ancient times when it
was first built and subsequently when Putnam’s
crew brought the embankment’s height back up to
its mid-1800s height). The iron objects and general
century house that once stood just outside the survey
Figure 2. Magnetic gradient map of Serpent Mound (the
small black arrow along the southern edge of the newly
discovered undulation indicates the location of a 1x5 m
excavation trench dug subsequent to the magnetic survey).
In addition to several linear anomalies that we have
yet to investigate, and could be drainage related, the
most surprising find in the magnetic data is the extra
undulation along the east side of the Serpent’s neck.
This arcing magnetic feature is in fact the same size
and shape as the extant undulations, or coils,
composing the Serpent’s body. The ground to the
east of the Serpent’s neck, the site of this interesting
find, has no topographic evidence of this “lost coil.”
Comparisons with several old maps (see Figure 3)
shows that this newly discovered undulation in the
Ohio’s Great Serpent Mound Surveyed
d Burks Jarro
Ohio Valley Archaeology Inc.
ISAP News 32 Page 7
Serpent was not visible in the 1800s, even in Squier
nd Davis’s map, which documents the Serpent
prior to ploughing—nor is the feature evident in any
other published maps of the site. The bipolar linear
feature crossing the apex of the new undulation
corresponds to the location of a wire fence installed
by Putnam’s crews in the 1880s.
r (ca.
5 cm thick at most) of light colored, silty soil
sitting atop reddish clay was found to match the
location of the magnetic feature (Figure 4). This soil
contained several hundred pieces of lithic debitage,
including a projectile point fragment that dates to a
period before the construction of the Serpent.
Figure 3. Nineteenth century maps of Serpent Mound.
In June of 2012 we excavated a 1x5 meter trench
across a portion of the arcing magnetic feature to
determine what, if anything, is still present of this
possible lost coil (see Figure 1, the black arrow
indicates the location of the trench). A thin laye
two-thirds of the trench ocation of the magnetic
nstruction of the Serpent’s current
ymer, and William Pickard 1996. Serpent Mound: A
ort Ancient Icon? Midcontinental Journal of Archaeology 21:105-43.
nd Mississippi, Together with an Investigation into the Archaeology of Butler County, Ohio. Robert Clarke & Co., Cincinnati.
erpent Mound of Ohio: Site Excavation and Park Construction. Century Magazine Vol.
XXIX (new series Vol. XVII):871-888.
48. Ancient Monuments of the Mississippi Valley. Contributions to Knowledge, vol. 1.
mithsonian Institution, Washington, D.C.
f Ethnology. Twelfth Annual Report of the Bureau of
thnology, 1890-1891. Government Printing Office, Washington, D.C.
Figure 4. West profile view of a 1x5 meter trench cut
across the new “coil”—the light colored soil in the middle
match the l
So, how was this extra coil missed in the many maps
made of the site in the 1800s? It is likely that this
undulation was not visible in the 1800s and had been
erased in antiquity. Its fill probably was used by the
Native Americans to rebuild the Serpent in the
configuration that we see today. The scant remains
of the lost coil show up so well in the magnetic data
because midden-rich sediment was used in its
construction and this material was not entirely
removed when the undulation was erased. If one
examines the basic geometry of the erased coil, it
looks like it could reasonably fit (geometrically)
with the body of the Serpent, but it would not fit
with the head as we see it today. Therefore, if this
erased coil is part of a complete (with head and
body) pervious iteration of the Serpent, then this coil
and the previous iteration of the head were erased
prior to the co
References Cited
Fletcher, Robert V., Terry L. Cameron, Bradley T. Lepper, Dee Anne W
Maclean, J. P.. 1879. The Mound Builders; Being an Account of a Remarkable People that Once Inhabited the Valleys of the Oh
Putnam, Frederick Ward 1889/1890 . The S
Squier, Ephraim G., and Edwin H. Davis 18
Thomas, Cyrus 1894. Report on the Mound Explorations of the Bureau o
... 500 BCeAD 200) or Late Prehistoric Fort Ancient culture (ca. AD 1000e1650) occupations (Abrams and Le Rouge, 2008; Clay, 2005; Cook, 2008 ), which suggests a long occupational history spanning >1500 years (Fletcher et al., 1996; Griffin, 1943). 1 Greenman (1934), Griffin (1943, Webb and Snow (1945: 341), and Webb and Baby (1957: 106) all believed that Serpent Mound was constructed during the Early Woodland Period, by people of the Adena culture. The assessment of Serpent Mound as an Adena construction was circumstantial and based mainly on the Adena cultural affiliation of a conical mound about 200 m southeast of the Serpent (Fig. 1). ...
... (Images provided courtesy of G. William Monaghan. Magnetometer map provided courtesy of Jarrod Burks.) 1 We recognize several taxonomic issues concerning the term " Adena " [Brown, 2005; Clay, 2005; Greber, 2005; Mainfort Jr., 2005]; however, for the purposes of this discussion and to maintain historic continuity, we will use " Adena " as a heuristic term of convenience. indicators for when the mound was built. ...
... The magnetometer survey (Geoscan Research FM 256 fluxgate gradiometer) provided images of near-surface anomalies, such as trenches, structural remains, and burned features. Magnetometer data were collected on a 12.5 Â 50 cm grid, and processed through Geoplot 3.0; the resulting image is displayed at ±5 nT (Fig. 1), dark is positive (Burks, 2012). Magnetometer imaging revealed an arcuate-shaped anomaly near the neck of the effigy that is similar in size, shape and form to the existing coils in Serpent Mound (Fig. 1A, B). ...
Full-text available
Effigy mounds occur across the midcontinent of North America but their cultural purposes and construction chronologies are rarely known and often controversial. Determining the age and construction history of monuments is important to relate religious symbolism, scientific knowledge, and cultural continuity to groups within a region. Based mainly on circumstantial evidence, researchers have long held that Serpent Mound in Ohio, USA, was constructed 2000–3000 years ago during the Early Woodland (Adena) or Middle Woodland (Hopewell) periods. Excavations in 1991 recovered charcoal buried at shallow depths (35–45 cm) in fill units of the mound and the 14C ages from two of these units indicated that Serpent Mound was built ∼900 years ago, during the Late Prehistoric (Fort Ancient) period, much later than originally thought. Our recent multidisciplinary work provides a more complex, robust construction history of Serpent Mound. We used geophysics to map the mound, and solid-earth cores to provide accurate stratigraphy and organic samples for 14C age estimates from the base of the mound. Bayesian statistical analyses of the seven 14C ages from Serpent Mound suggest that it was first constructed ∼2300 years ago during the Early Woodland (Adena) period but was renovated 1400 years later during the Late Prehistoric (Fort Ancient) period, probably to repair eroded portions of the mound. Modification of the mound is also indicated by a possible abandoned coil that is located near the head of the Serpent and visible only in the magnetometer survey.
... In any case, as explained by Zaleha and Romain (2014), "This feature is consistent with the scenario of Herrmann et al. (2014) that a portion of convolution 3 may have undergone erosion or damage in association with sinkhole subsidence or sub-mound drainage associated with the closed depression." 4. Another line of evidence suggesting that the effigy was repaired at convolution 3 is the discovery of another episode of prehistoric mound alteration. As Figure 8 shows, magnetic gradiometer survey found evidence for what has been called a "stealth" or "erased" convolution at the neck of the serpent (Burks 2012). This feature is not surficially visible with the naked eye nor is it visible in lidar imagery. ...
Recent radiocarbon dating (Herrmann et al. 2014) found that Serpent Mound was likely built during the Early Woodland period—around 320 BC. Herrmann et al. (2014) also suggested that the effigy was repaired or restored during Fort Ancient times, thereby accounting for the late prehistoric radiocarbon-dated samples recovered by Fletcher et al. (1996). The present article presents new data in support of the Early Woodland construction date. These data include lidar analyses, electrical resistivity ground imaging (ERGI) studies, and iconographic assessments.
The Mound Builders; Being an Account of a Remarkable People that Once Inhabited the Valleys of the Oh a Putnam, Frederick Ward 1889/1890 . The S X Squier
  • J P Maclean
Maclean, J. P.. 1879. The Mound Builders; Being an Account of a Remarkable People that Once Inhabited the Valleys of the Oh a Putnam, Frederick Ward 1889/1890. The S X Squier, Ephraim G., and Edwin H. Davis 18 S Thomas, Cyrus 1894. Report on the Mound Explorations of the Bureau o E