User:Sam.roebuck/Turf Wall

Turf wall
From Milecastle 49 to the western terminus of the wall at Bowness-on-Solway, the curtain wall was originally constructed from turf, possibly due to the absence of limestone for the manufacture of mortar. Subsequently, the Turf Wall was demolished and replace with a stone wall. This took place in two phases. The first (from the River irthing to a point west of Milecastle 54, during the reign of Hadrian, and the second following reoccupation of Hadrian's Wall subsequent to the abandonment of the Antonine Wall (though it has also been suggested that this second phase took place during the reign of Septimius Severus. The line of the new stone wall follows the line of the turf wall, apart from the stretch between Milecastle 49 and Milecastle 51, where the line of the stone wall is slightly further to the north.

In the stretch around Milecastle 50TW, it was built on a flat base with three to four courses of turf blocks. A basal layer of cobbles was used westwards from Milecastle 72 (at Burgh-by-Sands) and possibly at Milecastle 53. Where the underlying ground was boggy, wooden piles were used.

At its base, the wall was 6 m wide, and built in courses of turf blocks measuring 18 inch long by 12 inch deep by 6 inch high, to a height estimated at around 3.66 m. The north face is thought to have had a slope of 75%, whereas the south face is thought to have started vertical above the foundation, quickly becoming much shallower.