No one knows why pre-Columbian American Indians built a serpentine mound on a southern Ohio (U.S.A.) hilltop. And the mysterious formation's age remains a topic of archaeological debate.
      A state historical plaque at the earthwork's location declares that the mound may have been built about 900 years ago, rather than 2,000 or more years ago as archaeologists had thought. The plaque's message is based on a scientific radiocarbon-dating analysis of charcoal samples retrieved in 1991 from layers of the earthen serpent. Scientists said the radiocarbon analysis placed the origin of the charcoal samples between AD 1025 and 1215, supporting the theory that the mound was built by Fort Ancient people about 900 years ago. That makes sense because the Fort Ancient people had established a village and what may have been a burial mound nearby, said Bradley Lepper, an Ohio Historical Society archaeologist who helped retrieve the 1991 samples and wrote an article about the work.
      But there is debate. William Dancey, an Ohio State University associate professor of anthropology, said the older age estimate might be correct. Or, the correct answer might never be known because erosion and a 19th-century restoration of the mound may have forever altered key physical evidence there, he said.
      Dancey, a former teacher of Lepper's, said that although radiocarbon dating is regarded as a reliable method, the charcoal itself may have gotten into the mound from other sources long after it was built. Dancey said he still supports the earlier belief that the mound was likely built by the Adena people, thought to have lived in the area between 800 BCE and AD 1. The earthwork resembles a snake nearly a quarter-mile long uncoiling atop an Adams County bluff overlooking Ohio Brush Creek. There is no evidence that it was ever a burial mound, although burial mounds were found in the vicinity, archaeologists said. Some researchers think the serpent mound might have been laid out in alignment with astronomical observations.

Source: The Beacon Journal (7 February, 2000)