Wall Mile 20 [HB 176–7]
Until now, we have got used to walking by the road. Nowadays, west of Halton Shields, it sweeps round in a grand curve but the original line, with its abrupt angle, is preserved by the northern marginal field wall. Things are about to change, however. Once we have followed the road (and of course the wall) onto a new, slightly more southerly, course, we are required to cross the Military Road yet again (do you need to be told to be careful? Too late, you just have been). Now, to the south of us, we are greeted by the spectacle of the Vallum rolling downhill from Carr Hill farm. There are finer stretches of Vallum, but none you will see up-close and in-the-flesh by walking the Trail, so take a moment to enjoy it. The Trail wants us to negotiate an ingenious system of stiles taking us away from the verge and over a field entrance like slow-motion hurdlers. We shall take them in our stride, for the rewards, once we are let loose in the proximity of the Vallum, are worth the effort.
Ahead of us, the plantation on Down Hill itself is eye-catching in its own way, but cannot match the silhouette of the Vallum as it soars over the crest of the ridge. Walking towards it, we can make out all of the salient features of this rather curious outwork, but in the sort of detail we could only imagine before: the central ditch with its marginal mounds to north and south, as well as an unmistakeable upcast mound on the southern lip of that ditch.
As we climb up past the earthwork and reach the crest, we can now see ahead of us how this magnificent feat of earthmoving is all but removed to the west, first viciously by quarrying, then insidiously by ploughing. Looking back towards Carr Hill farm, we can also now appreciate that the Vallum has in fact made a vast angular detour to avoid the limestone outcrop of Down Hill, just as the Military Road does to the north. The curtain wall, however, bounds on regardless through the trees, accompanied by the ever-faithful (and, at this point, rock-cut) ditch. For a few metres it is relieved of the burden of the road, but it will soon be back.
Milecastle 21 (Down Hill) [HB 177; haiku]
Nothing survives of this milecastle, beyond the suggestion that it ought to have lain somewhere close to where the track meets the Military Road. Like the Vallum, it has been quarried away.