Comprises a long stretch of revetment walling that accommodates Thomas Telford's Holyhead Road (nprn 402349) on the east side of Nant Ffrancon, as it climbs to the south to reach the Ogwen Pass; the earlier turnpike road (nprn 418712) is clearly visible beneath.
Source: Extract from Cadw Scheduling description.
RCAHMW, 22.11.2004