I visited a reconstructed Mandan House site in South Dakota near the North Dakota border. It was near the park that was the fort for Custer in the 1870's when he went into the Black Hills to remove miners and see for the Army what gold was being found there. There is a book called "Custers Gold" . The Paha Zapa was a huge Vatican for the Plains tribes of that area, and was shared like the quarries around Pipestone, MN. I have been to a ceremony at Bear Butte in SD back in the 70's during the trouble at Pine Ridge. There were still elders who had family members at the battle of the greasy grass.
I have been to the Great Circle Mound in Newark OH, and have seen that ditch inside the circle along its inside wall. Many speculate this internal moat was used to reflect the stars at certain times of the year. It is similar to an artificial horizon one sees at a planetarium. Ours at the college here actually has building and a watertower in this silhoutted artificial horizon. to make it appear as if you are outside. Far too much light these days and more than there were when I was an undergrad here in the 60's.
On Feb 21, 2010, at 11:25 AM, STEVEN HILGREN wrote:
"The circular enclosures vary from 300 feet to nearly 1,000 feet in diameter and the rectangles appear to be of a similar size. They are accompanied by ditches most often located inside the walls rather than outside where you might expect to find a defensive moat. "
This ditch inside the walls was also found at the mandan village site.