Cargill Fort


Although nothing remains of this site beside the Bridge of Isla, the fort platform may be viewed from the minor road leading to the Blackhill signal station, which was itself off-bounds during my visit in April 2004 being enclosed within a young pine plantation used for grouse-breeding. The reason for its construction was apparent enough, there being a direct line-of-sight to the nearby fort.

The (Flavian?) Auxiliary Fort N.G.Ref.: NO166379

This first-century (probably Flavian) fort lies at the crossing of the River Isla just to the south of Inchtuthil, an undated fortlet also lies nearby (see below). Although the Cargill fort and the Inchtuthil fortress undoubtedly served different functions and therefore may have been contemporary, their close proximity probably points to one structure preceeding the other, most likeley the smaller Cargill camp first. How the nearby fortlet fits into the scheme of things has yet to be determined.

The Cargill fort was discovered from the air (by CUCAP) in 1977 lying on the left bank of the River Isla just above its confluence with the Tay. The fort is aligned to the north-west, facing the crossing of the Isla and has an attached annexe on the north-west. The minor axis was proved by excavation (in 1980 and 1981) to measure 340 ft. (c.104 m) in width, while the major axis can only be estimated at about 640 ft. (c.195 m), giving an area of just under 5 acres (c.2 ha). The fort rampart, about 20 ft. (6 m) wide, was of clay and turf resting on a corduroy of timber which in places survived to a height of six or seven courses; it had been rebuilt in places using layers of turf interleaved with layers of gravel and/or clay. A berm 8 ft. (2.4 m) wide separated the rampart from the innermost ditch, 10½ ft. wide by 7¼ ft. deep (3.2 x 2.2 m), a median ditch with a similar profile lay 20 ft. (6 m) beyond, and the third and outermost ditch, 12 ft. wide and 6 ft. deep (3.7 x 1.8 m), lay 27 ft. (8.2 m) further out.

The internal buildings, which have been partially excavated, were of timber and included a granary at least 81 ft. (24.69 m) long and 30 ft. (9.1 m) wide with a loading platform fronting onto the via principalis. Like the rampart, there are signs of at least two phases in the interior buildings. A spread of heavy cobbles representing the intervallum road or via sagularis was also noted during trenching across the interior of the fort. The ditches have “parrot-beak” inturnings at the gateways, which have been found at several known Flavian forts in Roman Scotland. Pottery recovered from the site include two sherds of Flavian mortaria.

Beneath all of the Roman occupation levels there are signs of pre-Roman plough ruts, which probably explains the elaborate defensive system surrounding the fort, as the encampment had apparently been placed upon land previously cultivated by the local native tribe, the Cargill fort (NO 166379): a second brief programme of investigation at the larger of the two Flavian forts, discovered by Professor St Joseph close to the confluence of the Tay and the Isla, revealed the south-west rampart to be some 6.4 m (21 ft.) wide, of turf and gravel with timber strapping and with a 4.3m (14 ft.) spread of heavy cobbles representing the bottoming of the intervallum road behind. The SW-NE width of the fort was established as 103.6 m (340 ft.) internally. Another section revealed that the front of the north-west rampart was rebuilt in clay and turf. Within the annexe three large construction-trenches for a timber building were located, all parallel to the rampart and two of them dug through a spread of clayey turf representing demolished rampart material. The section yielded a Flavian mortarium rim. The granary partially excavated in 1980 in the south-east quarter of the fort was shown to be at least 24.69 m (81 ft.) long, with no less than seventeen parallel foundation-trenches, each 9. 1 m (30 ft.) in length, with a post-hole for a loading-platform or projection at the edge of the via principalis.” (Britannia, 1982) Some 33 km to the SW [of Inverquharity], a new fort was recorded at Cargill (NO 166379), on the left bank of the River Isla, near the modern crossing and about 500 m above its confluence with the Tay; the fort, which lies only 300 m E of the known fortlet at Cargill Mains, 70 has an area of c.2 ha (5 acres) and faces NW towards the existing bridge, with a defended annex on the NW front, enclosing the entire bridgehead. Exploratory excavation in 1980 and 1981 confirmed the evidence of crop-markings indicating triple ditched defenses on the NE front, and identified timber structures, including a granary, within the adjacent portion of the interior; two structural phases were recognised in the internal buildings. A section across the NW defenses failed to locate a ditch on this side but revealed that the rampart here had been twice repaired, on the second occasion after a fire that had apparently destroyed timber buildings in the annex. A small, but remarkably informative, assemblage of burnt Samian found during later agricultural operations immediately outside the SW gate of the fort confirmed the merge artefactual record produced by excavation, suggesting that the fort had not continued in occupation much, if at all, beyond A.D. 85; such evidence accords well with the fact that, at the NE and SW entrances, air photographs show the outer ditches curving in towards the inner to produce the ‘parrot’s beak’ terminal found on many Flavian fort sites in the north.” (Maxwell & Wilson, 1987)

References for Cargill

  • Recent Discoveries in Roman Britain from the air and in the field by I.A. Richmond in J.R.S. xxxiii (1943) p.47 & fig.8;
  • Air Reconnaissance in Britain, 1955-7 by J.K. St. Joseph in J.R.S. xlviii (1958) p.91;
  • Roman Britain in 1965 in J.R.S. lvi (1966) p.198;
  • Britannia xii (1981) p.319;
  • Britannia xiii (1982) pp.335/6;
  • Air Reconnaissance in Roman Britain 1977-1984 by G.S. Maxwell and D.R. Wilson in Britannia xviii (1987) p.16.

Roman Roads near Cargill

Probable Military Road: SW (9) to Bertha Probable Military Road: NE (10) to Cardean (Tayside) Probable Military Road: NE (3.5) to Inchtvthil (Inchtuthil, Tayside) SW (7.5) to Grassy Walls