Wall Mile 45 [HB 278–9]
A short walk along the northern fringe of the upcast mound for the ditch takes us to the road, Walltown quarry (as was), and time for a decision. Now is your chance to take a break from the Wall and explore the Roman Army Museum at Carvoran. Strictly speaking, Carvoran was a Stanegate fort (falling between the regular forts at Birdoswald and Greatchesters – the Vallum swerves to the north to avoid the fort, huffily excluding it from the Wall zone), but we need not be so picky that we will stride on past and ignore it, especially in the light of its recent refurbishment which definitely makes it worth a visit. Besides, it gives the Roman military context to the whole Wall by explaining army organisation and so on.
So, whether you choose to visit the museum or just carry on along the Wall, after joining the road we turn right and soon see the entrance to Walltown Quarry, which we will either walk past or turn into, according to our preference. The former quarry, now a nature reserve, has a small shop with public conveniences next to the car park. Follow the path east out of the car park, our route curves round to the north, keeping the large upstanding mound to our left. At the point where the path starts to turn to the east again, we are close to the site of Turret 45b, which – left on a pinnacle – collapsed into the quarry in the 19th century and which provided an object lesson in the danger of quarry proximity to monuments that was to become relevant again in the 1930s, as we shall see. Musing on such things, we can carry on along the path until it takes us up past the quarry face to a gate in the south-east corner of the nature reserve, Once through that, we double back on ourselves and head north, keeping the stone wall immediately to our left until we see the curtain wall loom into view, just before it plunges over the quarry edge.
Climbing dramatically upwards, before weaving around outcrops of whinstone, we are now aware that the geology has changed for the first time since we left the Cumbrian coastal plain. Starting at Thirlwell Castle, we have ascended the Whin Sill, the outcrop of dolerite that dominates the central sector of the Wall and provides the tactical landscape for the mural barrier, as well as having donated the term ‘sill’ to geology. It is a characteristic of the Whin Sill that it slopes downwards to the south (known, appropriately, as the ‘dip slope’) and is accompanied by bands of sandstone and limestone to its south. It thus provided two key elements for the Wall’s construction: sandstone for the curtain wall itself and limestone for the mortar. Dolerite is too hard to be worked easily (the major reason it was preferred for road stone in more recent times, hence quarries like Walltown) so the Roman troops generally avoided trying to dress it as facing stones, although it did sometimes end up in the core. Thus the happy coincidence of the tactically favourable terrain, the presence nearby of necessary building materials, and the comparatively short distance between the coasts meant Hadrian’s Wall was placed in the Goldilocks Zone for northern frontiers.
Wall Mile 45 is one of the most spectacular and oft-photographed sections of the Wall, and the adaptation of the curtain wall builders to this terrain is interesting to observe. Climbing up from its unintentional terminus above the beetling cliff of the quarry face, the curtain wall turns a corner of about sixty degrees to the east, nicely rounded on the outside but angular on the south face (and so reminiscent of milecastle corners), keeping a comfortable distance from the edge of the cliff that matches the width of the berm elsewhere, where the ditch is present. Winding around some outcrops, it then plunges down into our first ‘nick’; the ‘Nine Nicks of Thirlwell’ are in reality glacial spillways, caused by melt-water when the ice was retreating at the end of the most recent Ice Age. Only pedants will care that there are no longer nine of them, due to the actions of the aforementioned quarry. This is the viewpoint for the famous Alan Sorrell reconstruction of the Wall at Walltown Crags. On the way down, some rather spectacular buttressing is undertaken to get over one particularly troublesome outcrop. This particular spillway still drains water, but now from the boggy land to the south, so has been provided with drainage slots at its base like those we have already seen further to the west. The curtain wall immediately begins to climb again, its coursing impressively levelled on footings that more casually follow the slope and even stepped as it goes around a slight corner. Then it is but a short hop to the site of Turret 45a, which is a rather interesting example of its kind.
Turret 45a (Walltown)
Interesting? Already, after only a few examples have come our way, turrets can scarcely be called interesting. This one is. Cast your mind back to Pike Hill signal tower, which we saw just after Turret 52a. That 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.
The curtain wall continues for a short distance to the east before it vanishes, consumed by Greenhead Quarry (which, unlike Walltown Quarry, remains more as less as it was when abandoned: a mess). We can follow the fence round and start to climb the Sill and soon we see an impressive sight: the next bit of wall, perched on the edge of a quarry face (and often with crows ridge soaring above it). Gaining a bluff, we find ourselves looking down on another stretch of curtain wall, partly excavated and consolidated. Most people don’t know this is here and walk straight past it, which is a pity as it is particularly evocative of how the consolidation process was undertaken (and, in this case, abandoned). Immediately to the east, the curtain wall is covered again and only a few tumbled stones poke through the turf (affording an excellent opportunity to compare the two states of the wall) and as we follow it up to a low platform, we reach the site of Milecastle 45.
Milecastle 45 (Walltown) [HB 278; haiku]
Milecastle 45 (Walltown) has never been properly excavated, but the robber trenches dug to remove its walls (and their associated spoil heaps) are very clear and serve to delineate the structure. Try if you can to recall Milecastle 48 next to the Poltross Burn and reflect upon the two extremes of preservation and presentation.