Summary of site:
In an area around Cumber, south south east of Claudy, there is a flat-topped feature of around 4kmē, consisting of sands and gravels, lying in a hollow in the local bedrock.
After a period of deposition following the initial ice retreat, ice dammed the Faughan valley creating a glacial lake with a surface 126m above modern sea level. Meltwater flowing into the lake (probably from the south) carried glacial debris, creating possibly two flat-topped deltas of cross-bedded and ripple-marked sands which were then violently scoured into channels by torrential flow and later filled with cobble and pebble gravels. This episode was followed, after the lake had drained, by a period of intense cold when the deposit froze to depth and ice wedges were able to form (six have been seen in the area).