The following guest blog post was written by Robert Fletcher, currently a staff archaeologist/anthropologist for the Historic Preservation Division of the State of New Mexico. A substantial part of his early archaeological career, however, was devoted to elucidating the age and purpose of Serpent Mound.
Although I’ve somewhat lost touch lately with current happenings in Ohio archaeology, being occupied with archaeology in Egypt and the American Southwest for the past couple of decades, I recently came across the exciting news that new dates had been obtained for Serpent Mound. This caught my attention since I was the lead investigator of the research team whose excavations at Serpent Mound in 1991 led to a peer-reviewed publication of the results in the Midcontinental Journal of Archaeology (Spring 1996). This investigation was part of a ten-year effort begun in 1986 by Terry Cameron, his father, and myself to first, make an accurate map of Serpent Mound. Later, as our knowledge and interests expanded, we attempted to understand more of the prehistoric significance and, possibly, the construction era of the effigy. Ultimately we were fortunate enough to recruit Dr.’s Bradley Lepper and Dee Anne Wymer (our esteemed paleobotanist), and field archaeologist extraordinaire William Pickard for our actual excavation efforts.
We employed generally accepted excavation practices and documentation during the project and eventually obtained two charcoal samples from clearly cultural levels, which were submitted for AMS radiocarbon dating. Both samples produced identical dates of 920 +- 70 years B.P. We also encountered charcoal apparently associated with a chert flake well below the base of the mound. This charcoal produced a date of 2920 +- 55 years B.P. A hill contour projection in one of our figures clearly indicates where the original hill surface should be seen in the profile and it was noted where expected.
Based on the dates, iconography, stratigraphy, and other evidence (including a review of everything in the Ohio prehistoric literature published from 1843 to 1996), all of us came to the conclusion (not without considerable argument) that the Early Fort Ancient period had the best explanatory value as a date for construction. (If anything, the dates were a little disappointing to me – I was secretly hoping for something even earlier than Adena!). There were also numerous discussions, and presentations in various venues, at the time with other members of the Ohio archaeological community. We gave a preliminary version of the paper at one of the Ohio Archaeological Council meetings (in fulfillment of our grant requirement), which resulted in an invitation by the MCJA editor to submit a paper, which we did. The point is our efforts were not conducted in some sort of an archaeological vacuum. Our findings were tentative and clearly stated as such a number of times in the article, which reflected the latest research at the time and the only in-ground excavation conducted into the Serpent Mound effigy since Putnam a century previously.
It is quite encouraging to note that a 2011 CRM project by ASC Group was able to confirm Putnam’s discovery of both Adena and Fort Ancient components in the “Village site” areas south and west of the present museum. Of special interest was the buried ‘A’ horizon found just north of the large conical mound by ASC Group during their investigation of the site. Daniel Weintraub and Kevin Schwarz, the authors of the report, found the date significant because it indicated “the continued use of the area surrounding the conical mound long after Adena occupation of the site. In addition, the possibility of ritual activity associated with the Adena conical mound by the Fort Ancient peoples raises questions about the relationship between the two cultural groups’ occupations and possible continuity in the use of the site.”
I have thought for quite some time now that it is investigations such as ASC’s, focused on non-effigy areas that hold the most potential for advancing our understanding of Serpent Mound’s temporal placement and the prehistoric occupation sequence on the ridge top.
I do have questions about the recently announced Early Woodland dates for Serpent Mound. As I understand it, the charcoal for these dates was derived from core sampling. One well-known issue with core sampling (as opposed to a Phase III data-recovery excavation in metric intervals) is that it is subject to a number of uncertainties, not least of which is sediment compaction in the tube, which can lead to considerable depth skewing and would make the absolute in-ground location of any charcoal samples acquired using this method questionable. Soil coring is generally employed during the preliminary stages of a project to determine the extent of a site, and/or find the most useful areas to excavate so we don’t unnecessarily damage cultural resources. It is not generally used to specifically determine absolute depth and context for any datable material recovered in the core – that kind of precision usually requires excavation.
Until we can see a peer-reviewed publication on the latest dates, the jury remains out, and in any case, the findings may or may not necessarily demonstrate any compelling need for a dramatic reinterpretation of the currently-postulated Serpent Mound construction date. None of us who were part of the 1991 excavation team has any particular emotional attachment to a Fort Ancient construction date – it is simply where the evidence pointed. Being but another milestone in the on-going saga, our results are subject to reinterpretation – or confirmation – by (hoped for) future investigators with new and better technologies. Things change and science marches on. Our 1991 investigation was another chapter in a story that began at least a thousand years ago and continues to this day.
Robert V. Fletcher