This is an oval embanked enclosure set in a slight hollow to the north-east of a Roman fort (NPRN 95476) and some 50m north of its parade ground (NPRN 89404). It is about 39m north-south by 37m, enclosing a level, boggy area about 33m by 27m. There are entrances at the north and south ends. The monument is crossed by a disused tramway.

This feature is identified as a small Roman arena or amphitheatre, the only example known on a Roman military settlement in Wales and the borders apart from those at the legionary fortresses of Chester & Caerleon (NPRN 95650). All three examples are found close by parade grounds, equally rare in the region.

John Wiles, RCAHMW, 3 March 2008