“…Serpent Mound is the preeminent effigy mound in North America yet the age of its original construction is the subject of on-going debate (Herrmann et al, 2014;Lepper, 2018Lepper, , 2020aLepper, , 2020bLepper et al, 2018Lepper et al, , 2019Monaghan and Herrmann, 2019;Romain, 2019;Romain et al, 2017;Romain and Herrmann, 2018). Attempts to obtain chronometric dates for the mound have, so far, yielded only terminus post quem dates, because none of the dated samples can be reliably linked to its original construction.…”