The central cavity and its sediment fill are interrupted by two diagonal 50-meter (160 ft) high bedrock ridges that connect the brim to the central peak. Using high-resolution seismic, it was found that the bedrock is locally covered with a thin veneer of glacial till overlain by 5–10-meter (16–33 ft) of glaciomarine and postglacial sediments. The discontinuous nature of the rings results from either partial burial of the rings under these sediments or partial erosion of the rings.[1][2]