The earthworks of a possible Roman temporary camp at Derwin Bach were intially identified from the air in 1969, when the western corner was recorded (St Joseph 1973, 241). Re-examination of this coverage has identified faint traces of the southern corner (Davies & Jones 2006, 98) and close scrutiny yields parts of the south-east & north-east sides, allowing the complete plan to be plotted.

The camp circuit describes a trapezium roughly 200m north-west to south-east by 170-200m, enclosing an area of about 3.7ha. It occupies the butt of a south-east facing spur and would have faced this direction towards the Pen Llystyn fort (NPRN 301056) across the marshy valley of the Afon Dwyfach.

Examination of the western corner on the ground showed that the bank was about 3.0m wide and was fronted by a 2.5m wide ditch.

Air Photos: CUAP AYJ.47, 51; RCAHMW coverage

Sources: St Joseph in the Journal of Roman Studies 63 (1973), 214-246
Davies & Jones 'Roman Camps in Wales & the Marches' (2006)

John Wiles 31.05.07