Bathymetric, seismic reflection, and satellite data have revealed the common existence of a new type of carbonate bank margin—"scalloped margin"—throughout the Gulf of Mexico and the Caribbean region. These large (up to tens of kilometres across), irregular, convexbankward embayments are interpreted as predominantly erosional features produced by large-scale failure of platform margins. In tectonically active areas they may be triggered by earthquake shocks, whereas in stable regions they may more likely be the result of undercutting by dissolution and/or deep-water currents. Scalloped margins are common in the south-eastern Bahamas; this suggests that these relatively small, isolated Bahama banks may be erosional remnants of once larger platforms. The processes that create scalloped margins may result in erosional deep-water carbonate basins and, potentially, the demise and disintegration of carbonate platforms.