Wetlands within the lakeshore include bogs associated with sandscapes, perched bogs, lagoons, alder thickets and beaver flowages. These wetlands contain unique flora and fauna and add a considerable amount of ecological diversity to the lakeshore. Bogs dominated by sedges, wetland shrubs and sphagnum mosses often occur in the filled-in lake basins that are located just inland from sandscape dune ridges. The larger bogs on Michigan, Outer, and Stockton Islands have lagoons with floating and submersed aquatic species. Bogs found on poorly-drained summit plateaus are often smaller and have poorer bog floras than their coastal, sandscape counterparts. About one-third of the Islands coasts consist of Precambian sandstone ledges and bluffs. Local vegetation on these rock faces depend on the microhabitat and can vary from common willows and weed species, to subarctic rarities and species with calcareous tendencies. Steep reddish clay bluffs are vegetated with small trees of balsam poplar, white birch, red maple and showy mountain ash.