But the most recent evidence again supports the Adena culture as the first builders. Serpent Mound was built on a site where ...

Serpent Mound, south of Dayton and east of ... I’ve had occasion to visit a few times because I adore visiting the Mound Builder era sites around the area, as well as other Indigenous sites ...

location of the Serpent Mound -- perhaps the best-known of the Mound Builders' animal effigies. The 1,348-foot-long writhing snake sits on a high bluff and appears to be swallowing an egg.

The charcoal could be from old Adena fire pits that were dug up and incorporated into the effigy by Fort Ancient or even later mound-builders. Does knowing the age of Serpent Mound really matter?