This was is an arched masonry culvert and embankment built in the early 1820s probably by the engineer Joseph Jones of Ystradgynlais, and funded by the London Indigo Merchant John Christie (originally from Stirling), as part of the Brecon Forest Tramroad from the Swansea Canal at Cae'r-lan over the uplands of the newly enclosed Fforest Fawr to the Tramroad Wharf near Sennybridge. This part of the scheme included a parallel road which survives as an earthwork & construction quarries flank the culvert on both uphill sides. Published as part of Stephen Hughes, 'The Archaeology of an Early Railway System: The Brecon Forest Tramroads' (RCAHMW, Aberystwyth, 1990).

Stephen R. Hughes, 07.09.2007.