Detailed descriptions, information on access to sites which can be visited easily, a glossary, chronology, local information and museums are in:-
Lynch, Frances, 1995. Gwynedd: A Guide to Ancient and Historic Wales. London, HMSO for Cadw: Welsh Historic Monuments
Brief notes and access details for Industrial Archaeology sites can be found in:-
Gwyn, D and Williams, M, 1995. A Guide to the Industrial Archaeology of N W Wales. Association for Industrial Archaeology.
Detailed descriptions and discussions of many of the illustrated sites can be found in the following four volumes. All are out of print, but can be consulted in local libraries. The interpretation and chronology of some sites has been superseded by more recent work:-
Royal Commission on the Ancient and Historical Monuments of Wales. An Inventory of the Ancient Monuments in Caernarvonshire: Vol I – East (1956); Vol II – Central (1960); Vol III – West (1964). London, HMSO
Bowen, EG and Gresham CA, 1967. The History of Merioneth, Volume I. From the Earliest Times to the Age of the Native Princes. Dolgellau, Merioneth Historical and Record Society
For broad-ranging surveys of the Welsh historic landscape and a discussion of the techniques of aerial photography:-
Davies, J, 1995. The Making of Wales.
Stroud, Sutton Publishing for Cadw: Welsh Historic Monuments
Musson, Chris, 1994. Wales from the Air: Patterns of Past and Present. Aberystwyth, Royal Commission on the Ancient and Historical Monuments of Wales
More detailed descriptions and illustrations of the excavations at Bryn y Castell and Crawcwellt, with access details, are in:-
Crew, P, 2009. Iron working in Merioneth from prehistory to the 18th century. Merfyn Williams memorial lecture No.2. Maentwrog, Snowdonia National Park/Plas Tan y Bwlch
All of these volumes have references to other relevant publications.
Originally the home of Ellis Evans, Sheriff of Merioneth in 1600. The house and gardens owe their present form to William Oakeley in the 19th century. Since 1975 Plas Tan y Bwlch has been the Environmental Study Centre for the Snowdonia National Park.