A section of well-preserved sinuous trackway or drainage leat running north from a small tarn on Coed Bryn Bras. It measures approximately 115m long by 3m wide with an upcast and revetted bank on the east side and sunken by 0.6m in the centre. The site is shown on both the current and 1st Edition OS mapping. The site (as depicted on the 1st Edition OS mapping) is either an access trackway diverted from the main driftway onto the mountain to service a longhouse (NMR 523829) or is a drainage leat that may have provided power for a mill further down the slope (outside of the study area and in modern plantation). P.J. Schofield, OA North, 14th December 2011.