In November 1868, the mound was quarried for gravel by local residents; this excavation continued until the miners had reached the center of the mound, where they found multiple limestone burial vaults. These vaults were built as squares, 3 feet (0.91 m) on each side; each contained a skeleton that had presumably been placed in a seated position. The vaults were stacked from the mound's floor to a position just underneath its summit; each was separated from others by a small amount of gravel. Eight skeletons were removed from these vaults and sent to the Smithsonian Institution.[2] Findings from the mound have led to the conclusion that it is a work of the Adena culture.[1]
Despite the damage done by the amateur excavation, the Mann Mound is still a significant archaeological site and the second largest extant mound in Butler County. It was recorded by an archaeological survey published by J.P. MacLean in 1879,[4] and in 1971, it was recognized for its archaeological significance when it was listed on the National Register of Historic Places.[1]
