Miamisburg Mound — Public Lands Institute

Ordovician448-446 Mya

~448 to 446 Mya Late Ordovician Drakes, Whitewater, and Liberty Formations, interbedded gray limestone and shale 60 to 150 feet thick, buried here under glacial till; the mound stands on a till-capped bluff about 100 feet above the Great Miami, whose valley is a preglacial channel filled with Wisconsinan sand and gravel.

Epoch

Late Ordovician (Cincinnatian Series, Richmondian); Pleistocene till and buried valley fill

Native lands Glossary →

Adena culture (roughly 800 BCE to 100 CE), who raised the mound in stages to an original 68 feet and 300-foot diameter, the largest conical mound in Ohio and in the eastern United States at 54,000 cubic yards of earth · Myaamia (Miami), for whom the river and the town are named · Shawnee (Shawanwaki); the Great Miami valley a principal north-south corridor between the Ohio River and the Miami and Shawnee towns upriver; Shawnee and Miami ceded southwestern Ohio via the Treaty of Greene Ville, August 3 1795, two years before Zachariah Hole built his stockade at this bend of the river.

Displacement & Tenure

Cession 11: Treaty of Greene Ville (1795). The bluff lies north of the Symmes (Miami) Purchase in the Congress Lands between the Miamis, surveyed into six-mile townships after 1798 under Israel Ludlow and sold through the Cincinnati land office; Hole's Station stood here from about 1797, and Emanuel Gebhart, Jacob Kercher, and John and Peter Treon platted Miamisburg on February 20 1818, auctioning 90 fifth-acre lots. Charles F. Kettering bought the mound and made it a park in 1920; it passed to the state in 1929, and the Ohio History Connection owns the mound while the City of Miamisburg maintains the 37-acre Mound Park around it.

Shadow History

The mound gave its name to the plant across the road. A 180-acre tract adjoining the park was selected in 1946 for Mound Laboratory, the first permanent Atomic Energy Commission facility built after the war, to continue the Dayton Project's extraction of polonium-210 for the polonium-beryllium initiators of early atomic weapons; construction began in February 1947 and the plant ran from 1948 to 2003, adding tritium component production in 1954 and tritium recovery from dismantled weapons in 1969. In 1969 an underground waste line ruptured and released plutonium-238 in dilute nitric acid into the soil; during remediation a severe storm eroded contaminated clay into the drainage that feeds the remnant Miami and Erie Canal and on into the Great Miami River, and 1974 offsite sampling found plutonium-238 in canal sediments substantially above background levels. EPA added the plant to the National Priorities List on November 21 1989 after volatile organic compounds appeared in monitoring wells in 1986; the Great Miami buried valley aquifer below was designated a sole source aquifer by EPA in 1988. The billion-dollar Department of Energy cleanup finished in 2010, groundwater treatment and monitoring continue, and institutional controls bar residential use and new drinking water wells. NIOSH has since added three Special Exposure Cohort classes covering Mound workers, the first for employees between October 1 1949 and February 28 1959. The mound's own contents were taken in 1869, when an excavation sank a shaft from the summit to the base with two lateral tunnels, reducing the mound from 68 feet to its present 65 and opening a bark-covered burial 8 feet down and a log-lined vault 28 feet below that.

Ecology

The mound is held in mown turf with 116 steps to a summit platform; the surrounding park is picnic ground and second-growth hardwood on the bluff slope above the Great Miami floodplain.

Hydrology

Great Miami River, about 100 feet below the mound; a remnant reach of the Miami and Erie Canal runs between the bluff and the river; the Great Miami buried valley aquifer beneath the valley fill is an EPA-designated sole source aquifer.

Acreage

GPS

39.6276° N, 84.2809° W

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