Sandy Lake ware, a late precontact to early postcontact archaeological manifestation, was first identified in central Minnesota by Cooper and Johnson (1964). Since then, few studies about this ware have been completed. It is considered to be part of the Psinomani culture and occurs across a large area of central North America, where it persisted from about A.D. 1000 to 1750. Archaeological sites with Psinomani components often occur in regions where wild rice grows. It is likely that the people who left behind Sandy Lake ware were ancestral to the Eastern Dakota in central Minnesota and the Assiniboine in southern Canada. The Psinomani and Selkirk composite likely represent the material remains of an early Assiniboine and Cree alliance.
Three problems related to Sandy Lake ware were identified, including classification uncertainties, associated cultural questions and its northwestern extent; the latter had never been fully assessed. By studying this ware and comparing it to other pottery, some classification complications were simplified. A synthesis of present information about the Psinomani culture was also completed. Collections from sites across a large area in south central Canada were examined to determine the northwest extent of Sandy Lake ware. One of the first inventories of shell tempered pottery, likely Sandy Lake ware, was compiled for the study area. The Stamped type is now known to have been recovered several 100 km farther northwest into Canada than previously determined
