Wall Mile 30 [HB 214–15]
If we move a little further on from the site of the milecastle, we can stop by a large rock protruding from the base of the ditch. Finally, we reach the most famous part of Limestone Corner. Wedge holes can still be seen in the top of the pinnacle where the attempts to split the whinstone were given up (whin naturally contains vertical cracks or joints, along which it will split); it must have been a bad day for the dtich-diggers.
To the south of us, large chunks of whin have been discarded down the slope, the largest of which (subsequently split into two by frost action) has been estimated as weighing around twelve tonnes (naturally, there is no record of anybody having actually weighed it; this is a guesstimate). Such pieces probably had to be removed with sheer legs, a technology with which the Roman army were not unfamiliar.
We must now plod on, crossing the ditch and then over a stile, taking us to the north of it and onto the upcast mound. Now we can admire those roadside drystone walls (they are easier to see from either side than from the road, due to the changes in level since the road was built). As we saw earlier, the larger blocks, curiously familiar from our perambulations next to the curtain wall, are interrupted by regular lines of throughstones.
The need for an all-weather east–west road across the isthmus became apparent after the Newcastle-based Marshall George Wade failed to intercept the Jacobite rebels in 1745 (who, ironically, exploited his new roads in Scotland to effect a swift passage into England at Carlisle). Wade got bogged down at Hexham during a horrendous blizzard and gave up. He died in 1748 and had nothing to do with the construction of the road, but sadly you will still find it called ‘Wade’s Military Road’ in less-well-informed sources than this, dear reader.
Construction of the Military Road began in 1749 with a survey from west to east, undertaken by two military engineers, Dugal Campbell and Hugh Debbeig (the latter serving later at Wolfe’s side at Quebec), detached from William Roy’s Military Survey of Scotland. Their drawing of the survey was subsequently published, unattributed, by John Warburton. The actual work of building the road and walls was contracted out to civilian companies (unlike the other military roads in the Highlands, which the Hanoverian army built) and did not always stick to Campbell and Debbeig’s recommended route. The road had a macadamised surface (compacted gravel on a stone foundation) and its original form can be seen in one of J.P. Gibson’s photographs, taken near Carrawburgh. The model lounges on the road in a way that would be suicidal nowadays and it will be apparent that successive metallings have now raised the road considerably.
Continuing west along the field, we finally reach a stile and then another crossing of the Military Road. As usual, you will need to exercise care here. On the south side, we encounter the Vallum (the constructors of which merrily ploughed straight through the whin outcrop at Limestone Corner without batting an eyelid). The Military Way (the Roman road that ran along behind the curtain wall) is now perched on the north mound of the earthwork. We press on westwards, past some recent quarrying next to the Military Road. The car park at Carrawburgh is now in sight and just before we reach it, we arrive at the location of Milecastle 31.
Milecastle 31 (Carrawburgh) [HB 215; haiku]
Milecastle 31 lay just east of the car park, part of one of the robbed walls having been found during the construction of the modern facility. Needless to say, there is nothing to be seen now.