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THE ROMAN GASK PROJECT ANNUAL REPORT 2010 D.J. Woolliscroft and B.Hoffmann |
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Fieldwork Excavation and survey at Woodhead For example, our 2008 annual report related aerial and geophysical studies of a series of candidate tower sites beside the Roman road stretching south from the southernmost known installation to date: the fortlet of Glenbank, to the north of Dunblane. In the event, the three proved unlikely to be Roman, but we still have high hopes of future discoveries in this area, if only because Glenbank seems such an illogical place for the system to end. More recently, however, our attention has been diverted further north. Until recently it had seemed all but certain that the Gask ended at Bertha fort, which lies at the confluence of the Rivers Tay and Almond, just upstream of modern Perth. Moreover, this appeared perfectly logical. Roman frontiers often end on significant topographical features, such as rivers, coastlines or mountain ranges. They also tend to terminate at full sized forts like Bertha, not at minor installations such as Glenbank in the south. To be sure there were additional forts heading north into Strathmore (Fig 2) and a number of - mostly 18th century - antiquarian writers claimed to have seen a Roman road running north towards Strathmore, from the Tay bank opposite Bertha, through Stormontfield and Byres.
For some time we have been interested in a ring ditch site called Woodhead, near Wolfhill, between Bertha and Cargill (Fig 2). This was discovered from the air by the RCAHMS and appeared in the National Monuments Record simply as 'enclosure': in other words as a generic, unidentified round cropmark. Subsequent air photographs provided more context, setting the feature within a wider knot of (probably Iron Age) roundhouses, but the original feature remained very different: having a much heavier, double ditch, and looking for all the world like one of the double ditched watchtowers at the southern end of the Gask. Certainly, a better observation position is hard to imagine, with a spectacular view of approaching 30 miles of the Highland fringe, which includes the Dunkeld Gap, the strategic pass where the Tay emerges into the lowlands. Our 2006 annual report presented the results of a geophysical survey of the site, which made it appear still more like the southern Gask towers, by showing how nearly identical they were in size. The survey also suggested (but did not prove) that the ditches had an entrance break, another universal feature of Roman timber towers in northern Britain, but something that had not been detected here from the air. If the site was a tower, it could be a major breakthrough, because its location, well out of sight of Cargill, made it far less likely to relate purely to the fort, than Black Hill. Consequently it could be the first real hint that a Gask style system did continue further north. But the remote sensing data, however tantalising, was not strong enough to permit certainty by itself. The site simply had to be excavated. 2010 saw a break in its usual cereal cultivation and excavation took place, with the kind permission of the Stathallan Estate and the farmer, Mr Croal, whose constant interest and kindnesses throughout our time on the land were very much appreciated. The site proved to be better preserved than anticipated, with features, such as an internal hard standing surviving, and not just the deeper ditches and postholes. As a result, despite a difficult clay subsoil that formed concrete on dry days and soup in the rain, good results were obtained. Before the excavation there had been a number of possible alternative identifications for such a site, including a prehistoric farmstead, a barrow, or even a more recent windmill. No trace of roundhouse foundations was found, however. Nor were there any signs of a burial pit or cist, and dating evidence detailed below rules out a post-Roman date.
No datable artefacts were recovered from either site, but carbon samples from Woodhead allowed a C14 dating to the 1st century AD, or the late 1st century BC. Assuming that the two are indeed Roman watch posts, therefore, it seems probable that they belonged to the 1st century, Flavian occupation, rather than the mid Geophysical Surveys Doune
Nevertheless, much valuable data was obtained (Figs 4-6), of which, perhaps, the most important was the discovery of the fort's south-western rampart and gate. The SE gate had been seen from the air: the only gate to be detected in this way but, as such things tend to be symmetrical and excavations some years ago had cut part of the NW defences, the opposite gate position could be extrapolated with confidence. Roman forts generally had four main gates, set in an essentially rectangular defensive circuit with rounded corners. Usually, the gates in the short axis were set centrally, whilst those in the long axis were off centre, often roughly a third of the way along. Doune's NE corner was visible from the air and, although there was just room between the SE gate and the almost sheer drop down to the river at the southern edge of the plateau for a symmetrically opposite corner, there was little room to spare to allow this side to be significantly longer (unless we assume that the plateau has been eroded back more than seems plausible since Roman times). It thus seemed likely that the SE and NW gates lay centrally on the fort's short axis. That meant that the fort's orientation depended on the missing SW and NE gates. Roman forts had a definite front and rear, which can usually be determined from the position of the long axis gates. These were linked by an internal road called the Via Principalis, which (as the gates were off centre) divided the fort into two unequal sections. The shorter of the two, the praetentura, was the front and is usually thought to have been set so as to face the direction from which any enemy seemed likely to come. In the case of Doune, this might have been expected to be the NW, towards the Highlands, but the excavations had not provided enough data to be sure. The geophysical results removed all ambiguity. The south-western defences are now proven, and do indeed follow a line that would put the SE gate on the short axis centre line. The resistance survey showed the NW gate to be almost exactly where it had been predicted, whilst both the magnetic and resistance work revealed different aspects of the SW gate and a short stub of road emerging from it. Contrary to expectations, this lay about a third of the way from the fort's east end, not the west, so the site faces 123o east: more or less straight down the Teith valley, and almost exactly towards the hill that now carries the Wallace Monument, above Stirling where another Roman fort has long been looked for. This, in turn, allows us to forecast, with confidence, that the NE gate will lie in and around the road entrance to the school grounds. Moreover, it should be possible to test this prediction next year, for the area currently includes a house for the caretaker, but there are plans to demolish it to make room for an extension to the school, with excavation as part of the process. The Gask Project is occasionally teased by colleagues for our insistence that our large scale geophysical surveys should include both resistance and magnetic coverage. After all, we are told, magnetic surveying is so much quicker than resistance, and surely the two produce much the same picture. Doune has shown, yet again, that this is wrong, however. For example, the resistance data provided a dramatically better image of the ditch system. We were able to confirm the aerial and excavation evidence that the fort had a triple ditch, something rare in this area. And we can now go further because it appears that all three pass right around the site, whereas the closest parallel, Cargill (Fig 7), has three ditches on only part of its circuit.
The resistance survey also confirmed aerial hints that the outer ditch tuned inwards on either side of teach entrance, to form what have been nicknamed 'parrot beak' gates. These are a common characteristic of 1st century forts in the north, but only one triple ditch parrot beak system had been known before: again at Cargill. There the middle ditch did not turn in; it simply continued on until it met the in-swinging outer ditch. But, as no parallel was known, it was impossible to say whether that arrangement might be typical, and it was useful to see the same pattern repeated at Doune. Moreover, the Doune magnetic data showed another feature that our geophysical and aerial work elsewhere suggests might be a standard characteristic of parrot beak gates: an inward swing of the ramparts on either side of the entrance, so that the gates themselves would sit at the end of a re-entrant. The two features make obvious tactical sense when used in combination. For they would create what amount to funnels that could be all but guaranteed to cause confusion amongst even a well ordered rush on the gates. An attacking force would have been able to pass through the outer ditch on quite a broad front. But it would then find itself rapidly compressed as the outer ditch swung in towards a much narrower inner ditch break. Some of its outermost members might even be pushed into this ditch, but the others would be forced inwards, causing confusion in the ranks at a time when they would already have been under fire from the fort. They would next pass down the rampart re-entrant, becoming still more compressed and disordered, to an entrance just c. 6m wide, and would there be faced with the barrier of the gate itself, whilst under enfilading fire from the rampart funnel above and with their escape route blocked by their own comrades surging on from behind. The result would be a killing ground and the funnel would have become a trap, although how much extra defence the third ditch would offer over the more usual twin arrangement is less certain. No internal buildings were detected by the larger scale geophysical work, but there are hints of a structure towards the SE corner in the small scale radar test. The magnetic work did, however, reveal linear features that probably represent parts of the praetentura's internal street system. The resistance survey, on the other hand, picked up the intervallum road, with a series of small circular features set in the rampart back alongside it, especially towards the SE corner. The latter probably represent rampart ovens. Excavations towards the western end of the fort were able to study a group of such ovens in detail some years ago, and our resistance survey at Cardean, in Strathmore, picked up similar structures. A number of external features were also detected. Firstly, the magnetic survey revealed a linear feature branching off the fort's outer ditch at the SE gate and heading down a gully towards what is now the site of Doune Castle (Fig 4).
Inchtuthil fortress The fortress itself (Fig 8, I) is a little over 50 acres, but it stands above the Tay, on a wider plateau of approaching 200 acres, which also contains a (probably post-Roman) Iron Age promontory fort (Fig 8, IV) along with number of other Roman fortifications. The eventual hope is to scan almost the whole of this area, which will make it one of the largest geophysical surveys ever conducted in Scotland. 2009 had seen ourselves, and Peter Morris, of Blairgowrie Geoscience, covering close to 100 acres of magnetic survey (including most of the fortress), plus a smaller (but still huge) area of resistance work, and we had hoped to complete most, if not all of what remains to be done this season. Sadly our plans had to change for agricultural reasons, but we were still able to do a good deal of useful work. Firstly, there is a small Roman fortified enclosure to the east of the fortress, to the north of the modern pathway onto the site (Fig 8, V). This has been partly eroded by the river and can look small and somewhat inconsequential on plans of the site. But this is only because it is so dwarfed by the fortress, and it is actually a major fortification in its own right: the size of a normal Roman fort. Its function remains unclear. It has been variously christened the 'Redoubt' and the 'Stores Compound' by previous workers, but only really for something to call it and not as a genuine attempt to assign it a role. It is certainly Roman, but little more could be said. One attempt had been made to examine it, during the late Sir Ian Richmond's long program of excavations on the fortress in the 1950s and 60s. A few small trenches were opened inside the defences, but no signs of structures were detected. The enclosure lies in woodland, however, and tree roots make life very difficult for an excavator, so this blank could only be regarded as provisional, and given the remarkably clear picture obtained of the internal fortress buildings by the 2009 magnetic coverage, there seemed to be a very real chance that the same technique could be used to find internal details in the 'Stores Compound' too. The area becomes almost impenetrable in summer, but the dense undergrowth dies back enough in winter to allow access, and in February 2010 Peter Morris undertook a magnetic survey (Fig 9).
At the opposite end of the plateau is a large, multi-phased temporary camp (Fig 8, II), roughly the same size as the fortress, along with what had appeared to be a much smaller Roman camp (8, III). But Peter Morris was also able to subject most of the latter to magnetic survey, before it vanished under a game cover crop, and the results are particularly interesting. The site was discovered from the air, and nothing remains visible on the surface. It
At the same time, despite frozen ground and bitter cold late winter weather, our program of metal detecting outside the fortress continued. The purpose of this work has been to recover artefacts from the ploughsoil (only) which are by definition removed from any stratified context and which would otherwise simply be destroyed by continued erosion through cultivation. We are withholding the find distribution plans for the time being to avoid giving assistance to night hawks, but two factors have become apparent from the cumulative 2009 and 2010 results. Firstly there is a very substantial amount of lead working debris from outside the fortress, which suggests a significant industrial quarter. Interestingly, there are 18th century accounts of local lead working, from a vein on nearby Birnam Wood: a substantial hill at the mouth of the Tay gorge, opposite Dunkeld. The particular significance of this ore is that it was argentiferous: in other words it contained silver, which could be extracted by cupellation. The Roman army is known to have made a particular point of seeking out and exploiting (or managing the exploitation of) precious metals, often so quickly after the conquest of an area that one wonders whether the locating of such resources may have been a priority for pre-conquest intelligence work. Such metals were, after all, the foundation of the imperial coinage. If any part of the Birnam lead vein survives, and we can find it to take samples, it should be possible to compare them to the lead being recovered from Inchtuthil to see if it really was the local ore that was being worked. But for the moment this is just a fascinating possibility. The second significant find, is a substantial and growing body of coinage. The site has seen several excavation series, under Abercrombie, at the start of the 20th century, Richmond, in the 1950s and 60s, and Barclay & Maxwell more recently, but it had yielded only a handful of Roman coins. The Gask Project work has quintupled this body to almost 60, thus making it one of the very few Roman sites in Scotland with an assemblage that might be considered statistically significant, and the material is being studied by Prof David Shotter of the University of Lancaster. The only other site in the north with a similarly large corpus and which, like Inchtuthil, also does not seem to be contaminated by later Antonine, Severan (or even late Flavian) activity is Elginhaugh, to the south of Edinburgh, and if the issue dates of the coins from Finally, there has long been doubt as to which side of the Tay the fortress lay in Roman times. At present the river runs to the south of the plateau, and despite considerable changes in course, it has done so since the first large scale maps of the area were produced in the late 17th century. There is little doubt, however, that the river does sometimes switch to the other side of the site.
Air Photography
Publications, outreach and publicity
As usual, the Directors have given lectures to a range of academic, student and amateur bodies, in addition to our normal teaching. As always, we made particular efforts to speak in Perthshire and its surroundings, with talks at Innerpeffray, Forfar and Glasgow, and both of us lectured in Perth. We also took a guided tour around Inchtuthil for Perth Archaeology The year also saw a number of publications. Our excavation report on the Gask fortlet of Glenbank appeared in PSAS, along with reports on the three sites already mentioned to the south, that had appeared as possible tower candidates, but which our geophysical work had shown to be indigenous. Birgitta meanwhile published three different glass studies, for sites in three countries, on two continents. There was one on the material found by the late Charles Daniel's excavations in the Fezzan, in Libya. One was on the glass from the vicus outside Rainau-Buch fort on the Limes in Germany and the third was for the vicus at South Shields, behind Hadrian's Wall. Other works went to press for publication next year, for example a re-evaluation of the evidence for the foundation date of Elginhaugh fort, an interim report on the Inchtuthil survey, and the publication version of David's paper to last year's International Congress of Roman Frontier Studies, on the role and anatomy of Roman towers. Other reports were written during the year but will not be published for some time, notably that for Doune, which will form part of the book we have been commissioned to produce, in which all of our fort surveys will appear together. Sponsorship and Acknowledgements The Project owes thanks, as always, to the farmers and land owners who have allowed us access to sites, and to Peter Green who does a wonderful job of maintaining our web site. Bill Fuller has continued in his indispensable role as pilot on all of our air photographic flights, and he also does a great deal of work turning David's air photo identifications into a proper computer searchable database. As already mentioned Peter Morris, Oliver O'Grady and Dan Boddice have partnered the Project on different aspects of our geophysical work and we must congratulate Dan, who passed his MSc in geophysics at Bradford with flying colours during the year, and won a funded Ph.D place at the University of Birmingham. As always, we are grateful to our many field volunteers, especially our long-standing geophysics and dig supervisory team: Rachel Hunt, Paul Murdoch, Keith Miller and now Tony Simpson. It was also a huge pleasure to welcome back one of our longest standing team members, Mike Murphy, who had not been able to join us for some years. The Future Out of the field, we plan to write up Woodhead and prepare more of the geophysical work for the book. We also hope to finish the report on our multi-season excavation at the Iron Age site of East Coldoch. Birgitta's book on the military history of Roman Britain should appear (which will of course include the Gask), as should her long awaited book on Cardean. We have been asked to write an interim piece on our continuing landscape survey of the Iron Age environment and settlement pattern around Inchtuthil, and both of us will again be writing papers for the Roman Army School. The Directors will continue to give public lectures where invited. Talks have already been arranged in Perth, Manchester and Weaverham, and more will no doubt be booked as the year goes on. All in all it should be another busy year and, as always, we are eager to start. D.J. Woolliscroft and B. Hoffmann. Our previous annual reports and completed research papers can be viewed free of charge on our Web site at: www.theromangaskproject.org.uk |
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