<P> In 1901 the Ohio Historical Society hired engineer Clinton Cowan to survey newly acquired lands . Cowan created a 56 by 72 - inch (1,800 mm) map that depicted the outline of the Serpent Mound in relation to nearby landmarks, such as rivers . Cowan also made specific geographical surveys of the area, and he discovered the unique astrobleme on which the mound is based . He found that the mound is at the convergence of three distinctly different soil types . Cowan's information, in conjunction with Putnam's archaeological discoveries, has been the basis for all modern investigations of the Serpent Mound . </P> <P> In 1967, the Ohio Historical Society opened the Serpent Mound Museum, built near the mound . A pathway was constructed around the base of the mound to help visitors . The museum features exhibits that include interpretations of the effigy's form, description of the processes of constructing the mound, the geographical history of the area, and an exhibit on the Adena culture, historically credited as the creators of the mound . </P> <P> Serpent Mound State Memorial is currently being operated on behalf of the Ohio Historical Society by the Arc of Appalachia Preserve System . It is a non-profit organization specializing in the preservation and protection of native biodiversity and prehistoric aboriginal sites in southern Ohio . </P>

Great serpent mound from the hopewell culture of north america is an example of