This structure consists of a doglegged revetment and bank leading down to a pool in the Nant Hirin. It is shown on the 1st edition 1:10560 Ordnance Survey map of 1891 but not labelled and is probably shown on the 1833 1" to 1 mile map as well. The northern part of the structure starts with a stone-lined revetment cut into the natural slope. This revetment was up to 1m high and ran north northwest to south southeast for 10m, then turned to the southwest for another 7.5m. At this point the revetment butted onto a grass-covered stone bank, 2m wide and 0.75m, high which ran for 12m down to the pool in the stream. J.J. Hall, Trysor, 2 December 2009