As a general rule, there were two turrets between each milecastle (so with intervals of one third of a Roman mile), but as we all know, general rules are made to be broken, and turrets were no exception. Pike Hill and Peel Gap were just two additional turrets we know of and there may be more awaiting discovery.
Banks East turret, curtain wall, and ditch
Turret 52a (Banks East) was excavated in 1933 and was the first piece of Wall in Cumbria to be placed into the guardianship of the Ministry of Works (in 1934). The road, which used to follow the line of the curtain wall closely, originally ran over the top of it, but has subsequently been moved onto the berm. The curtain wall to either side of the turret is, once again, the Narrow Gauge form that pre-dates the move to the Antonine Wall and is pierced at ground level by several drains, designed to stop water ponding against it.
The turret itself, being originally constructed free-standing and with the turf wall butted against it, is very clearly of a different build to the curtain wall. The butt joints between wall and turret are obvious and the turret protrudes to the north of the line of the curtain wall. On its north face is a fine plinth course and there are hints that it existed on the south side too. Why is the plinth course there? Nobody knows. Perhaps it marked a feature of the Turf Wall itself, such as the top of a vertical front ‘cheek’ (although turf ramparts were usually battered inwards so that they were narrower at the top than at the base, the lowest portion was sometimes vertical).
The chief distinguishing features of the turret are that it is square with an entrance at ground level (in this case at the eastern end of the southern side) and that it is recessed into the thickness of the curtain wall. A hearth lay against the west wall. As with all archaeological reconstruction, the higher up we look, the less certain we are about details. It is assumed it had entrances on either side at the level of the top of the Turf (and later Stone) Walls, although there are those who do not believe Hadrian’s Wall had a walkway or parapet on top (more of that later). As part of the Turf Wall, the front and back of this stone turret coincided with the front and back of the turf rampart, but when the stone curtain wall was provided, the turret was left to project slightly to the north (turrets to the east, built at the same time as the curtain wall, did not do this), so some scholars have suggested this means the curtain wall was lined up on those side entrances to the (presumed) walkway. Turrets and towers in the ancient world were generally intended to give a height advantage, so we can be fairly safe in assuming its top was higher than the Wall, although by how much is uncertain; part of the tumbled superstructure lies immediately outside the west wall. Equally, we do not know if it had a flat roof with a parapet and fighting platform or whether it was conventionally roofed. As you can readily see, what we know about turrets is far outweighed by what we have to guess.
Pike Hill signal tower
Just 205m to the east of Banks East turret there is another square stone tower, this time set at an angle to the line of the Wall. This is Pike Hill Signal Tower, positioned on the crest and cut by the same road that overlay the neighbouring turret, although only parts of two sides and one corner remain to be inspected. Fortunately, the south-eastern side contains the entrance at its southern end. The tower has been interpreted as a pre-Wall signal tower, probably associated with the Stanegate ‘system’, which was subsequently incorporated into the Wall, due to its advantageous position for signalling.
Lea Hill Turret (T51b)
Turret 51b (Lea Hill) now lies just to the north of the road, which has wiggled slightly southwards to leave the line of the curtain wall since we were last on it. This is another Turf Wall turret incorporated into the stone wall, so there are butt joints on either side to confirm this. In fact, the curtain wall is missing on the eastern side, so the facing stones on that side of the turret are visible. Inside, there was a stone platform against the north wall and a hearth in the centre of the ground-floor room. The ground-floor entrance was at the eastern end of the southern side. Look over the fence and, sure enough, you can see the ditch.
Recrossing the road, we go back through the small gate and rejoin the Trail, which eventually unceremoniously dumps us back onto the road to avoid another house. Heading east, we may note how the southern verge has an informal trampled path, a sure sign of the use of the road by traffic (including the AD122 Hadrian’s Wall bus, which sweeps along here every so often, taking up most of the width of the road) and walkers’ communal (and forgiveable) desire not to be run over. Soon we encounter our next turret.
Piper Syke Turret (T51a)
Closely resembling its twin to the west (insofar as it is not only similar in form but also lacks the curtain wall to the east), Turret 51a (Piper Syke) is another re-used Turf Wall turret. It too has a stone platform against its northern wall, a central hearth, and an entrance at the eastern end of its south side.
Birdoswald Turret (T49b)
Turret 49b, the entrance to which is on the right, is bonded to the curtain wall – in contrast to those already seen (52a, 51b and 51a) – and was never free-standing. Since it is on the Intermediate Wall, it was constructed after those to the east of the Irthing and before the move to the Antonine Wall. It was first excavated in 1911 and consolidated for display in 1953–5.
Willowford West Turret (T48b)
Next we arrive at the remains of Turret 48b (Willowford West). Excavated in 1923, the turret stands up to nine courses high. It has lost its south wall, but still gives a good impression of the limited space available within its ground floor. Before we move on, inspect the curtain wall immediately east of the structure. Note that the rear face is stepped (there is a foundation course, four courses of a plinth, then the main curtain wall) and that it soon changes, becoming abruptly narrower. This is our last set of wing walls.
Willowford East Turret (T48a)
The curtain wall foundations here are to the broad gauge (10Rft or 2.74–2.97m), as is Turret 48a. As we have seen before, short lengths of curtain wall on either side (‘wing walls’) were constructed at the same time as the turret, but then the width of the curtain is similarly reduced to only 8Rft, sitting on that broad foundation. We are coming to the end of the narrow/broad gauge saga, so make the most of it, for Turret 48a is one of the clearest demonstrations of this feature.
Walltown Turret (T45a)
Turret 45a is rather interesting. Pike Hill signal tower was a pre-Wall signal tower incorporated into the Wall; so is Turret 45a, as was evident when it was re-excavated in 1959 (it had previously been examined in 1883 and 1912). The curtain wall butts against it on either side and the tower-cum-turret, as with Pike Hill, has excellent views to the south and better views to the north than the neighbouring pre-Hadrianic fort at Carvoran. As with Pike Hill, the entrance is on the eastern side of the southern face.
Mucklebank Turret (T44b)
Turret 44b (Mucklebank) is unique in being set into a right-angled turn of the curtain wall, as it wends it way along the top of the crags. Still standing to about 1.9m high, it was excavated in 1892. Inside, the remains of an arch can be seen lying on the floor and that may originally have adorned the doorway.
Caw Gap Turret (T41a)
An undulating stretch of curtain wall includes the remains of Turret 41a, demolished almost to ground level when the Wall was briefly abandoned when the Antonine Wall was built. The recess within the curtain wall was filled in and the turret never reconstructed. There is another slight turn to a more southerly course and we are soon approaching the site of the old Shield-on-the-Wall farm house, which sat directly on the curtain wall but was later moved slightly to the south (where it still stands, amongst a clump of trees). This is the shallow re-entrant at Caw Gap and a length of ditch duly appears to the north to cover it.
Peel Gap Turret
Excavation in 1987 revealed an additional tower inserted into the Wall scheme, between Turret 39b (to the west of the road) and Turret 39a (up on Peel Crag), inserted into a blind spot that may well have originally been a transhumance route. The tower was an afterthought and its builders did not take heed of their fellows who had built the rest of the curtain wall out of sandstone, since they dressed whin stone to make its walls. A platform on the west side may have been the base for an ascensus, or stairway to the wall walk (which may or may not have existed… and so on). The best view of the tower is to be obtained by carrying on up the steps onto Peel Crag and looking back: no pain, no gain.
Sewingshields Turret (T35a)
Constructed on a broad gauge foundation but with a narrow gauge curtain wall, Sewingshields Turret, with its entrance at the eastern end of the south wall, was only briefly occupied before being demolished and its recess filled in.
Grindon West Turret (T34a)
Furnished with exceedingly small wing walls, this was another of those turrets which was only occupied in the 2nd century and, after abandonment, had its northern recess filled in. In the doorway, the curious will note the settings for the stone jambs of the door as well as the socket for the door pivot on the east side.
Coesike Turret (T33b)
This was a short-lived turret, with broad-gauge footings cut away by the narrow-gauge wall. For the first time, we find a (rather saggy) recess-filling wall added within the turret, probably to enable a wall walk to cross it safely. The doorway has been blocked, so the turret was evidently not completely reduced upon abandonment. Abandonment? The Roman army quit Hadrian’s Wall in the 140s in favour of a new, shorter, turf wall (the Antonine Wall) between the Forth and Clyde. This brief flirtation with the narrower isthmus did not last, however, and they returned south to Hadrian’s Wall in the 160s and recommissioned the older wall. A few features, including some of the turrets, were thought surplus to requirements and discarded.
Black Carts Turret (T29a)
Turret 29a (Black Carts), famously depicted in one of the woodcuts in Collingwood Bruce’s Handbook, survives to eleven courses within its recess, and has the familiar wing walls of a broad-gauge turret wed to the narrow-gauge curtain wall. It was first excavated by John Clayton in 1873 and subsequently re-examined in 1971. The threshold block in the doorway is of particular interest, since it retains the settings for the monolithic uprights that formed the door jambs, and the socket on the eastern side shows which way the door opened (remembering defensive doorways and gateways always opened inwards).
Brunton Turret (T26b)
In some respects, this is just another turret. However, it lies at an important junction, between the narrow wall (on its east side, marked by a short yet familiar wing wall) and by the narrow wall to the west, marked by the turret being bonded seamlessly with it. It is clear, then, that the decision to change from the broad to narrow gauge occurred at around the time the curtain wall gang reached this turret from the west (or did they start from here and work westwards, the next gang starting further east and heading towards Brunton?). Hadrian’s Wall is all about change, modification, and adaptation, and here this flexibility is plain to see. The threshold to the doorway reveals slots for monolithic stone jambs and a pivot hole (with a respectable channel) on the eastern side.
Denton Hall Turret (T7b)
The most easterly surviving turret is that at Denton Hall, embattled and proud, its site graphics care-worn and battered, all set within a small area of grass next to a bus shelter. A fine piece of broad-gauge curtain wall survives to either side of the turret, but it is worth noting that this was not excavated until 1929. When the housing estate was built to the south, just before the Second World War, examination of the Vallum produced building stones recording construction work by cohors I Dacorum.
The turret, with its door on the eastern side, has what may be a ladder base in the south-west corner, designed to afford access to its upper levels. Next to it was a hearth to provide some warmth and cooking facilities for those posted to it.
Vindolanda reconstructed turret
Whilst the Germans are busy reconstructing towers on the Obergermanisch-Raetische Limes left, right, and centre, in Britain there is bizarrely only one full replica of a Hadrian’s Wall turret, and that is at Vindolanda (which is, of course, not actually on the Roman Wall). This short, squat turret has been given a flat, crenellated top and is, arguably, out of fashion at the moment (although it will, in due course, doubtless come back into fashion given enough time; such are the vagaries of Wall scholars).
Tullie House Turf Wall turret
A partial Turf Wall turret has been reconstructed upstairs in the Borders gallery of Tullie House Museum and Art Gallery in Carlisle. It is not immediately obvious to the visitor (took me years to spot it!) but it is there, next to the length of simulated Turf Wall.