Mertoun Bridge that carries B6404 over the River Tweed was designed by James Slight and constructed by William Slight, finished in 1841 and used ashlar for the masonry.
The bridge carries the B6404 public road across the River Tweed near St Boswells. James Slight William Slight 1841 The masonry used is ashlar, and the stone is a reddish sandstone quarried nearby. 
