A complex of abandoned Lake Michigan beach ridges at Baileys Harbor, Wisconsin was investigated to establish the type, onset, and periodicity of ridge-forming processes. A further objective of the study was to place the development of the complex into the context of the postglacial history of the Great Lakes region.

Surface profiles were constructed, and samples of sediment and peat were collected and analyzed. Results of pollen and radiocarbon analyses were used to infer the kind and timing of climatic conditions affecting lake levels, ridge accretion, and peat accumulation. A suggestion is made for an asymmetrical rate of change between high and low lake levels.

The ridges accreted during four episodes of low or falling lake levels separated by three periods of high or rising water, during which erosion of earlier ridges occurred. Peat first began to accumulate in the interridge swales after the first erosional event, and construction of a truncating ridge began not long before 1,000 B.P. A pollen core extracted from behind the oldest ridge revealed a vegetational sequence that closely corresponds with post-Algoma lake-level fluctuations reported by other workers for the Lake Michigan basin.