Carrow Hill fort, Monmouthshire (NPRN 423337, ST 4300 9034)

Discovered on 29th June 2018, but most clearly recorded under ripening crops on 6th July, this site occupies the summit of a low hill WSW of Caerwent and south of the course of the Roman road. It appears as the cropmark of a bivallate ditched enclosure, the inner one 50 m square (0.23 ha), the outer 73 m square (0.5 ha). An annexe 52 m across is attached to its eastern side. The corners of both fort and annexe are beautifully rounded in military fashion. Although there is no clear indication of an entrance, such may have lain to the north where the ditch system is obscured by a modern lane. The ditch system, with an interspace of c. 12 m between the inner and outer ditch, resembles that of pre-Flavian military installations such as Hod Hill and Great Casterton , where a `killing zone? has been fashioned, with the outer ditch being of Punic form. In terms of size the nearest comparators are small forts of Flavian date in Scotland such as Inverquharity (0.36 ha), Gatehouse of Fleet (0.35 ha) and Mollins (0.4 ha), the last also possessing an annexe.

The fort's southern defences abut a pair of plough-levelled round barrows (NPRN 423338); the eastern smaller one, measuring 30 m in diameter, has a `keyhole?-shaped cutting into its centre from the north, potentially evidence for its modification by the Romans to form an oven or kiln.

This discovery is particularly significant insofar as, though of small size, it is the first plan of an auxiliary fort to be recorded in the Vale of Gwent. Its location 1 km south of the course of the Roman road is indicative of an early, and probably pre-Flavian date. Carrow Hill may possibly be linked with two other broadly contemporary sites: Chepstow, c. 13 km to the east, where a fort probably exists on the basis of early cremation burials and an associated Claudian coin, and Coed-y-Caerau, another probable early fort c. 5.5 km to the north-west, which encloses 1 ha and is situated on high ground overlooking the Usk valley and the site of the legionary fortress at Caerleon. Though originally included as a fort in Jarrett's 1969 edition of The Roman Frontier in Wales, Coed-y-Caerau was subsequently dismissed on the basis of its apparent integration into the defences of a complex Iron Age hillfort; further consideration leads to the conclusion that its Roman military credentials should be reinstated.

TOBY G. DRIVER, BARRY C. BURNHAM and JEFFREY L. DAVIES. RCAHMW July 2019