A clue to where the oldest bridge was probably located is in the 1877 map of Morriston which shows Old Bridge Farm between the Tawe and the back of Tirpenry St houses. . The land to the right of the new road, which follows the railway line that dissected the Farm, and the river are remnants of the fields ( opposite side of the River from Pant y Blawdd) it was in that area that the Nant flowed into the River
I had cause to look at one of those 19th century maps to over lay the "Nant" outflow map and noticed something I recall from my youth.. Near the canal in the spot where Rees & Kirby would eventually be located and Bush Road there is the outline of what looks like a large Wellington boot. It was what I think was known as the "Giants Foot"
Just walked up the river footpath and the Nant emerges on the far bank just after the painted walls end. There are large old dressed stones adjacent to the outflow and again on the near bank . Could these be the abutments of the old bridge or just very old river erosion protection. There is no evidence of other bank protection up or down stream.