The first mound-builders of the Ohio Valley, who buried their honored dead in log tombs beneath growing conical mounds and carved the famous Adena pipe.
Adena communities gradually blended into the Hopewell tradition after ~100 AD, their burial-mound customs elaborated by their successors.
The atlas holds 2 border frames for Adena — the shape you scrub through changes in 500 BC · 299 BC.
The best current accessible synthesis of eastern North American mound-building societies, covering the Adena burial-mound tradition of the Ohio Valley.
A readable history of the Eastern Woodland mound-building cultures and their study (broad context).