Last month, a team of Brazilian and Spanish archaeologists announced the remarkable discovery of monumental geometric earthworks - "geoglyphs" - in the jungles ofnorthern Bolivia and southwestern Brazil. Archaeologists Martti Prssinen, Denise Schaan and Alceu Ranzi report in the journal Antiquity that they have so far identified about 200 earthworks,including "perfect circles, rectangles and composite figures sculpted in the clay rich soils of Amazonia." 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. A 19th century explorer wrote that the indigenous people of the area confirmed that the structures were not fortifications, but were "an arrangement for parties." Prssinen, Schaan and Ranzi interpret this as a reference to feasts that might have been a part of ceremonies held at these places. They argue that the geometric precision of many of the enclosures "indicates that such places had highly symbolic significance for ancient Amazonians." Associated with many of these enclosures are sets of parallel walls framing broad, straight roads as much as 180 feet wide, connecting one enclosure to another. These might have been avenues for ceremonial processions. Their presence was revealed only by the leveling of the forest in this region. More are being exposed as the trees continue to fall. From my perspective, the most striking aspect of these discoveries is the amazing similarity of these South American earthworks to those built in southern Ohio. The Hopewell culture built geometrically precise enclosures to a comparable scale, including circles and squares, between about 100 B.C. and A.D. 400. Hopewell earthworks sometimes have ditches associated with them, and usually the ditches are on the inside of the embankment. At many Hopewell sites, parallel walled roads connected one earthwork to another, and most archaeologists now believe that the enclosures were places of ceremony and feasting. The Amazonian geoglyphs are only beginning to be studied and, so far, the archaeologists can report only one radiocarbon date of A.D. 1283. This would seem to make them about 800 years younger than the Hopewell earthworks. As more sites are dated, we might find that other enclosures are significantly older. The great distance between them and their apparent difference in age suggests that in spite of the startling similarities in architecture, there was likely no historical connection between these civilizations. Nevertheless, the archaeologist Stephen Lekson reminds us in his new book, A History of the Ancient Southwest, that we would be wise to not rule out such possibilities simply because we think these ancient South Americans could not have known what was going on 5,000 miles to the north. "Who are we to say what they could or couldn't do? Within very broad limits of environment and even more elastic limits of technology, anything was possible." It will be exciting to see what future investigations reveal about these marvelous earthworks that seem so tantalizinglyfamiliar to Ohioans.
Bradley T. Lepper is curator of archaeology at the Ohio Historical Society.