"The breadth iij yardis, the hyght remaneth in sum placis yet vij yardis."
Samson Erdeswick, visiting the Wall in 1574, says:
"As touching Hadrian's Wall, begyning abowt a town called Bonus standing vppon the river Sulway now called Eden, and there yet standing of the heyth of 16 fote, for almost a quarter of a myle together, and so along the river syde estwards."
Camden, who was here in 1599, saw it 15 feet high:
"Within two furlongs of Caervoran, on a pretty high hill the Wall is still standing, fifteen feet in height, and nine in breadth."
This must have been on the edge of the crags of the Nine Nicks of Thirlwall.
The breadth of the Wall is about 9 feet 6 inches at the foundation, and varies between 6 and 8 feet at the top. Dr. Bruce says: "Probably the prevailing width is 8 feet." The northern face is continuous, but the southern face has many offsets and insets, measuring from 4 to 12 inches, where variations in the width of the Wall have occurred. It is thought, therefore, that the work was done in sections, simultaneously, and that each superintending centurion was allowed to exercise his own judgment as to the width.
This brings us to what are known as "centurial stones," many of which are found along the line of the Wall. The inscription on these stones is always preceded by a reversed C, thus [reversed C], or an angle, thus, >, which indicates Centuria. It seems probable that they were set into the Wall to indicate that a particular section was built by troops under the command of such-and-such a centurion. The centurial sign is always followed by a name.
A deep V-shaped ditch defended the Wall all the way on the north side, except where it was protected by natural precipices. This ditch, at its greatest, was about 15 feet deep and 40 feet across at the top. It must have greatly added to the formidable appearance of the Wall on the side presented to the enemy.
No matter what the character of the material to be excavated, the ditch clings closely to the Wall on all the lower ground. It is hewn through basalt, sandstone and limestone with equal indifference.