Report of excavations in 1990

The full text can be found in D.J.Woolliscroft “Signalling and the Design of the Gask Ridge System”, PSAS, 123, 1993.

If we return to the dawn of archaeology on the Ridge,Christison’s original programme included excavations at Midgate (NO 02112047), which was then the most easterly Gask site known. Here, in addition to one of the standard timber towers, he also revealed a rectangular structure, which he took to be a second fortlet of the Kaims Castle type, lying immediately north of the Roman road and only a few metres east of the tower. Yet, although Christison’s report has remained the foundation for all subsequent studies of the area, this site seems largely to have been forgotten and, when mentioned at all, it is usually dismissed as non Roman, or even as a virtual figment of its excavator’s imagination. Indeed, an observer of the calibre of O.G.S.Crawford was able to visit the site and deny that anything was visible. It was thus felt important that Christison’s identification should be re-examined.

The Site
The importance of the fortlet site lies in its very close proximity to the Midgate tower, for its western ditch comes to within 13m of the tower ditch (link to 1990 plan) and it seems most unlikely that two Roman installations so close together could be exactly contemporary. Moreover, where a group of small Roman military sites, such as the Gask Ridge fortlets, form a distinct morphological class they might reasonably be expected to be contemporary inter-se, so that a date for any one installation is highly suggestive as a date for them all. This means that if Midgate is a fortlet of the same type as Kaims Castle and Glenbank, its position would cast doubts (in the absence of evidence to the contrary) as to whether any of the fortlets are likely to have belonged to the tower system.

The site lies at the eastern end of a small but distinct knoll, with its western half in the uncultivated south-east corner of a field and its eastern half in dense coniferous woodland. Despite Crawford’s denial, it is still clearly visible as an earthwork, although it has been heavily damaged since Christison’s day by the imposition of a WWII building (11.13m x 5.8m) in its interior. It consists of a rectangular enclosure, almost identical to Kaims Castle, measuring 20m N-S x 23m E-W internally (Kaims measures 20m x 22m), which is rather more square than is shown by Christison’s original plan. Like Kaims it is surrounded by the remains of an earth rampart which, as a surface feature, measures c4-5m thick, except in the west where it has been thickened to 11m since Christison’s plan was drawn, perhaps in connection with the WWII activity. On lower ground, 7m (on average) out from the ramparts (again as at Kaims), a single ditch can be traced as a shallow hollow, c3.5m wide, around all but the south side, where it has been destroyed by the modern road. The orbit of this ditch is rather less regular than is normal for a Roman installation, but this is inevitable, especially in the north, thanks to the shape and steep sides of the hill.

As Christison pointed out, the ditch is surrounded on its northern and eastern sides by a low mound. He interpreted this as a branch of the Roman road, to give access to the site, and his plan shows it continuing south past the site’s SE corner to the modern road, which largely follows its Roman predecessor, but is here probably on a slightly more northern line. In fact, however, the feature begins to turn, parallel with the ditch, at this corner before being cut off with it on the south side of the site and, as it consists mainly of rubble from the partly rock cut ditches, it is clearly an upcast mound. There is also a causeway across the western ditch, a little north of centre, and immediately north of a narrow channel through the rampart, which gives the impression of being an entrance. Neither feature appears on Christison’s plan, however, despite being conspicuously visible and so both seem likely to be modern. The channel, in particular, is probably meant for drainage of the interior and may again be connected with the WWII activity, and the causeway is probably its upcast mound. No other signs of an entrance survive, but this need not surprise us since Kaims Castle’s entrance had been carefully blocked and was also invisible before excavation. If the site is Roman, one would expect its entrance to have been on the south side, like that of the tower, facing the Roman road.

The Excavations
Christison’s excavations were largely confined to the interior and produced similar results to Kaims Castle, with no buildings being uncovered, only the remains of paving. Unfortunately, this area has now been so badly damaged by a combination of Christison, WWII activity and exceptionally heavy infestation by Rabbits, that it was thought unlikely that further excavation would produce useful results. Work was, therefore, confined to re-surveying the site and sectioning the ditch, an operation that Christison does not appear to have carried out. Two trenches were dug which, for reasons of accessibility, were grouped around the ditch’s north-west corner. T’1 (5m x 1m) sectioned the western ditch towards its northern end where it was just beginning to turn into the corner, whilst T’2 (4m x 1m) cut the western end of the north ditch, again just as it was turning into the corner. The two trenches were thus set at an angle of c70o and lay 7.6m apart at their closest.

Both trenches sectioned a “V” shaped ditch (link to section drawing) with a bottom slot or “ankle breaker”. In both cases the ditch was 2.5m wide and a little over 1.2m deep (1.27m in T’1 and 1.21m in T’2). In T’1 the ditch had been dug into firm, but easily worked yellow sand, but in T’2 it was cut through a hard, if brittle, purple/grey sandstone, so that its bottom slot is unlikely to have been the accidental result of cleaning. In both trenches the ditch had been deliberately back filled with a slightly brown, grey loamy material (L2), probably degraded turf. This was identical to material currently being produced (in disturbing quantity) from the remains of the ramparts by rabbit activity, and was probably the result of the partial slighting of those ramparts. In both sections this layer was essentially homogenous, but both showed a fair degree of gradation, with a preponderance of finer particles towards the bottom, consistent with a long period of water action since backfilling. In T’1 the backfill filled the entire ditch, with no detectable sign of primary silt, even in the bottom slot. This, coupled with the very sharply defined sides of the sand cut ditch, suggest that the ditch was back filled almost immediately after being dug, or re-cut. T’2 showed a deep silt deposit, some 0.5m thick in two layers. The lower, and much the thicker, was a 0.4m deep layer (L5) of silty purple/grey sand, similar to the weathering product of the natural bed rock, which in the area immediately outside the ditch had weathered to produce a thick (c0.2 – 0.25m) layer of soft, but here clean, purple/grey sand. Above this, the northern 2/3 of the ditch were covered by a c0.1m thick layer (L4) of clean grey silt. The boarder between these layers was somewhat vague, but that between them and the backfill (L2) was very clear cut, so that the two trenches taken together may suggest that the ditch was open and subject to natural silting for some time and then backfilled whilst in the process of being cleaned out. No dating evidence was found, but this activity must have taken place long enough ago for the backfill to have been graded by water action.

In the absence of datable material, one cannot honestly claim that the excavations prove a great deal. Perhaps the most that can be said is that nothing was found in either trench or in the general layout of the site that is other than consistent with a Roman fortlet. Unfortunately, however, a “V” shaped ditch, even one with an ankle breaker, is not necessarily diagnostic as Roman in northern Britain because a number of sites of Iron Age date, or at least culture, have also produced such ditches. Taken together with the surface survey and Christison’s results, however, the very close similarity of Midgate to Glenbank and Kaims Castle appears to make it virtually certain that these near identical, sites form a distinct class, which although presumably contemporary inter-se, do not fit comfortably with the towers. Indeed the writer would wonder whether there would ever have been any doubt over Midgate’s identity had it not been so close to its tower. Furthermore, Air evidence from Raith may have revealed a fourth member of this class, occupying the same site as a known tower and, therefore, actually over (or under) lying it. It is important to remember that none of these sites has yet produced dating evidence and so despite its traditional identification as such, Kaims Castle is no more proven to be a Roman fortlet than Midgate. A firm absolute date and a relative dating (vis à vis the towers) must, thus, await further excavations, especially at Raith.

A long term research project to study the Romans north of the Antonine Wall