We were in fact on guv property, TVA to be exact, supervised by the Corps of Engineers. Lots of little signs with castles on them nailed to the trees. The only guv artifacts nearby were transmission towers, a cable car across the river, and the old mosquito farms. Yes, they grew mosquitos for research, and the island used to only be accessible by boat, so they built a cable car from the bluffs across the river. The car and cable were still there about 15yrs ago, on the south side, with the motor removed, chained up to the south tower. TVA was very strange. They had a huge nitrate plant on the reservation, powered by the dam, and they decided that would be a dandy place for a nerve gas production facility. My uncle was in charge of it's refurbishment in the 60's, and it's upgrade to make binary nerve gas. Because nitrates are a primary ingredient in explosives, we always knew we were high on the Russian's "nuke it early" list. Fallout shelters sold well there. The area around the plant was huge piles of the stuff left after the fertilizer was made, a supposedly useless byproduct. Some smart guy made a fortune shipping it to Hawaii as it corrected some soil deficiecy in the cropping of pineapple in their soil there. TVA paid him to haul it away, too. TVA pumped so much mercury into the river that for about 10years, eating the fish was strongly discouraged. Made your kids look real funny.

We had our own Indian Mound, too, in the bottoms. I stand in awe of lines of subsistence level primitives with baskets full of dirt, building the damn thing by hand. It's about 200' on a side, a truncated pyramid about 100' high, down by the state docks in the flood plain.