The Hartley Fort Enclosure in Northeastern Iowa

Abstract

The Hartley Fort (13AM103) is a rectangular earthwork along the Upper Iowa River near its confluence with the Mississippi River in far northeast Iowa. This enclosure is a Stirling horizon Mill Creek–affiliated Terminal Late Woodland site with a ditch and stockade embankment. The site was later used as an Oneota burial site. The ceramics are overwhelmingly locally made Hartley ware and French Creek Cord-Impressed ceramics. Ceramics show direct interaction with the Initial Middle Missouri variant Mill Creek culture of northwest Iowa, as well as contact with the Cahokia site and contemporaneous sites in Minnesota and Wisconsin. Hartley ware appears to derive from Mill Creek ceramic types with local potters strongly influenced by Mill Creek ceramics. The Hartley Fort enclosure is like Mill Creek enclosures found in northwest Iowa, and one excavated small structure at the Hartley Fort resembles small Mill Creek structures. The Hartley Fort was an important, if brief, hub of Mississippian contact and interaction and exchange with regional Terminal Late Woodland sites during the Stirling horizon at Cahokia in the upper Mississippi Valley and with cultures of the prairie-plains border in the Missouri Valley.