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Prehistoric Raised Fields in the Upper Midwestern United States: An Innovation in Response to Marginal Growing Conditions

The prehistoric garden beds or ridged fields of Michigan and Wisconsin have puzzled Midwestern prehistorians for more than a century. Experimental studies and field reconnaissance undertaken by the authors indicates that the ridged-fields probably served to prevent frost damage to the crops grown on them. The problem of the origin of these features is discussed. While it is possible that the idea of ridged-field construction diffused from the tropical lowlands of Central or South America via Florida, Georgia and the central Mississippi River valley, the authors believe it to be more likely that the ridged fields of the Upper Midwest represent an independent innovation which occurred in response to peculiar local environmental conditions.