1. The monastic property at Marcross can probably be recognised in the complex of earthworks to the north-east of the village and extending on either side of the road known as the Heol Felen. The maximum extent of the earthworks is about 320m from E. to W. by 230m, and they are mainly concentrated in two areas, one on the N. side of the Heol Felen, 220m long N.E.-S.W. by 85m wide, and the other to the S. of the road, 210m long N.E.-S.W. by 70m wide.

B.A.Malaws, RCAHMW, 11 September 2001.

2. There is a copious spring at Marcross monastic grange known as 'Ffynnon y Coed.' It rises on the south bank of Marcross Brook, and formerly filled 'several ponds within the earthworks of the monastic grange. The spring rises in a ruined stone chamber of rectangular plan, about 1m across, and open to the north. It was capped by a modern concrete slab, but this has now collapsed.'
From notes written to accompany photographs by Paul Davis, January 2020
RCAHMW, 18th February 2020