Graeber / Wengrow 145: "On the shores of the Atlantic and around the Gulf of Mexico lie engimatic structures: just as remarkable as Poverty Point, but even less well known. Formed out of shell in great accumulations, they range from small rings to massie U-shaped 'amphitheatres' like those of St Johns River valley in Northeast Florida"
"spaces where hunter-gatherer publics once assembled in their thousands"