1. British Geological Survey. 1984. 1:50,000 Sheet 163 (Aberystwyth). Ordnance Survey: Southampton.
2. British Geological Survey. 1986. 1:50,000 Sheet 136 (Bala). Ordnance Survey: Southampton.
3. British Geological Survey. 1995. 1:50,000 Sheet 149 (Cader Idris). Ordnance Survey: Southampton.
4. . 1986. The Geology of the Country Around Aberystwyth and Machynlleth. Memoir of the British Geological Survey, Sheet 163 (England and Wales). HMSO: London.
5. Discussion on the palaeocurrent evidence of a northern structural high to the Welsh Basin during the Late Llandovery