Thanks Boogieman. RC dating on an old hearth *inside* the megalithic structures at the summit came out 2000 BC. It's a large, PreColumbian structure; some of the largest stuff (top of the knoll) was MUCH LATER reused as a foundation for a colonial-era house -- but the site is really ancient, and there's a non-fence spiral of stones that have no plausible connection to colonial construction of any kind, much less "root cellars". The site is interesting and worth a visit.
