In ever-wet climates, raised mires that are elevated several metres above flood levels can cover significant portions of coastal plains. Because peat accumulation may keep pace with moderate rates of base-level rise, the development of raised mires may reduced the areal extent of marine transgressions. Thick, low-ash coals are present immediately landward of many vertically stacked shoreface parasequences in Cretaceous state of the Western Interior of North America. We suggest that these coals formed in raised mires that stabilized shorelines for long periods of time. In such settings, the rate of sediment supply (including peat accumulation) to the coastal environment is partly a function of the rate of change in base level.