Llyn Cwm-byr, near Pumlumon
I keep on discovering fascinating landscapes. I discovered another one the other day, while travelling home from giving a talk in Bishops Castle, in the Welsh Borders. We took detour off the Newtown - Aberystwyth road and took minor roads via Devil's Bridge to Pontrhydfendigaid and Tregaron. I had been that way before without seeing much, but this time it was a real hot summer's day, with blue sky and fantastic visibility.
This is part of Wales's empty quarter, with a rolling -- almost prairie - like -- landscape of broad river valleys, wide depressions with lakes in them, and hilly areas with gentle slopes. This is the core of the Cambrian Mountains and the main watershed of Wales, with some streams flowing west and others flowing east -- but no glaciated troughs. During the big glacial episodes this area has been at the heart of the Welsh ice cap -- so there has been very thick ice sitting on this landscape -- but it has done virtually nothing in terms of landscape modification. The ice has been effectively stagnant, and probably cold-based, maybe with occasional aerial scouring but no streaming. The whole landscape reminded me of parts of the basalt plateaux of NW Iceland, except that here there are the remnants of a very old fluvial landscape which has been largely unmodified for millions of years.
Must try to get back there soon, so that I can take a more careful look.......
The Cambrian Mountains of mid-Wales, between Aberystwyth and Newtown. The undulating "watershed plateau" is clearly seen in the centre of the map. The brown-coloured area is the highest part of the plateau, around Pumlumon.