How many archaeological investigations encounter something very different from that which might have been expected at the outset? Perhaps a number, but the site on Church Hill at Calstock is a case par excellence. Here, a project set up to investigate medieval silver mining on the Devon side of the river Tamar was extended to include investigation of a recorded medieval administrative centre on the other side of the river in Cornwall where silver processing was said to have taken place. Subsequent geophysical survey did confirm the smelting activity but in addition, and remarkably, it also picked up the distinctive outline of the defences of a Roman fort. As a result, the author of this BAR volume was plunged unexpectedly into the role of excavation director of part of the fort's defences in advance of the threatened expansion of the nearby church burial ground. This has led to Smart presenting us with evidence for a new Roman military establishment in the far south-west of Britain (although he has not neglected the later archaeology of the site as the title of the volume so clearly illustrates).

S. provides a standard stratigraphic account in chronological order but he first sets the scene with the lively story of the expanding research aims, the geophysical survey and the different direction which the project took when the survey was examined. The Roman fort, from extrapolation of the geophysical results, is thought to enclose an area of about 2.1 ha. S. explores the raison-d’être for its location and points to the fort's dominating position on the upper navigable reaches of the Tamar, where he suggests an anchorage may have been located. S. believes that the fort could have been supplied by coast-hugging craft bringing goods from Gaul first off-loaded from sea-going ships further up the Channel coast at Topsham some 6 km to the south of the Exeter legionary fortress. S. makes this suggestion on the basis that the closest known seaport to Calstock at Mount Batten, Plymouth has a finds assemblage focused on second- to fourth-century material, and thus was not active as a military port. For the coarse wares a predominance of locally made gabbroic vessels in the recovered pottery assemblage is noted by S. to suggest a reliance on existing markets; this would support an argument that for at least some indigenous peoples in the South-West of Britain the Roman arrival on these shores would have been beneficial. The period of occupation of the fort is proposed as late Neronian to c. a.d. 75–80.

Excavation was limited primarily to the defences, a road leading west from the fort and a probable fabrica set against the western rampart (presumably a measure against fire-risk) where iron-smithing took place. Also examined were post-trenches thought by virtue of their position in the fort to represent barracks and there was a small exposure of the via praetoria. One of the more tantalising discoveries is described by S. as a ‘polygonal’ enclosure. Known from geophysical survey to be surrounding the fort, the enclosure ditch was trench-evaluated and found to have a profile which may be described as Punic; a label which S. concedes implies a Roman origin. S., however, while seeing the ditch clearly as defensive in nature, is uncertain whether it was a Roman military work or was dug by the Iron Age occupiers of a pre-existing hillfort that became redundant when the army arrived. S. provides plausible support for the latter of these two scenarios citing the Iron Age hillfort enclosures at Cadson Bury and Bury Down in Cornwall (C. Weatherhill, Cornovia: Ancient Sites of Cornwall and Scilly 4000BC–1000AD (2009)) which are of a comparable size to that posited at Calstock, but ultimately S. leaves the reader to ponder the question.

The report is well illustrated with clear excavation plans and sections and detailed attention to the specialist reports, which S. utilises well in his discussion chapter. S. must be congratulated for acting on the threat posed and reporting on a Roman military site in Cornwall, thus adding to the few known examples in this far-western county, although, as he states, further discoveries may be expected.