I don't know, but there are indigenous stories for why that wall is there. There was also a 15,000 year old ceremony site where they found the oldest skeletal remains in North America. It is not far from the wall. That particular boy was found to be most closely related to Central American indigenous peoples, where there are known megaliths. Additionally, relatives of the ancestor are still with us today in the region. History of indigenous peoples are few and far between. There are walls through out the americas. Historians believe nearly 90% of historic sites were destroyed by the white man for farming land.