The Lost Road and the Welsh Potosi.
There was once a road connecting Glaspwll with distant Ponterwydd, and hence to Devil's Bridge, but it's difficult even to detect its course on modern maps, and I've wondered why it fell into disuse. Richard Colyer, in his book "Roads and Trackways of Wales", speculates that the road might have been a medieval pilgrims' way, the route over the hills being used in preference to the longer routes along the valleys to reach the monastery at Strata Florida. He writes that it was shown on early 17th Century maps as a route linking Glaspwll-Gwaunbwll-Dolrhuddlan-Bwlch y Styllen-Dinas- Ponterwyd.
I've not had a chance to explore it, but local farmer Nick Fenwick knows the area well and has supplied me with some photographs of what remains of part of the track today, as it leaves Glaspwll along Cwm Castell. Initially it's totally engulfed by forest, although it later emerges into open sheepwalk above Cefn Coch farm.
Scientist Michael Faraday followed the route in 1819, and was greatly unimpressed by its bleakness.
An 1824 map shows quite a major road from Glasbwll, going west of Cefen-Coch farm, via Esgairfraith Mine Works and west of Dolrhyddlan, crossing Nant Camddwr, passing close to Caneinog and east of Blaen Ceilan, then joining the road from Bont Goch and Gogerddan, and on to Pont Erwydd [all names sic]. The road is shown again on an 1829 map (where I've accentuated it for clarity). George Borrow goes into some useful detail on his 1854 walk of this section between Machynlleth and Devil's Bridge, and it's obvious from his account that the road was in places hard to follow even then. From his musings we learn of the Welsh Potosi mines.
There used to be a great deal of mining activity in these parts, the Esgairfraith/Esgairhir copper and lead mines being developed by Sir Carbery Pryse from about 1691. The mines were known as "the Welsh Potosi", after the famously rich Potosi mines in Bolivia, and warrant a mention on Cowley's map of Cardiganshire in Dodsley's 1744 Geography of England. Sir Carbery died in 1705, but production continued until about 1708. More mining activity followed in 1760 and 1788, 1839-1849, 1850-1857 and various other dates until 1904. However, it was at its zenith in the 1800s.
Dolrhyddlan was the location of the Eaglebrook or Nantygagal (= Nantycagl) mine, which was first worked for copper and lead in about 1700-1722. It was re-opened in 1853-1865, but eventually closed again in 1875. So both the above mines would have been in operation at the time of Borrow's walk.
A map published in 1909, based upon a survey of 1885-1887, shows Cefn-coch farm (still there today), but with the road between Glaspwll and Esgairfraith reduced to a footpath. Gwaen-bwll is also shown, but today has disappeared from the scene, apparently engulfed in the Dyfi Forest - and Bwlchystyllen farm, present on this map, is now in ruins.
I think it's reasonable to assume that, although there may well have been a track here from medieval times, it grew in importance duing the Welsh Potosi years, and declined rapidly with the cessation of mining operations.
Finally, does this explain why there's a Nant Llyn Gŵr Drwg up behind Glaspwll? Could this be a link with the other end of the road, Devil's Bridge, named after the old Gŵr Drwg himself? Just a thought.