South of the turnpike road, and behind a small house, called Beggar-bog, is a low freestone crag, which exhibits some quarry-like excavations, filled with the chippings of stone. It has probably furnished material for the Wall, the stone being of the same character. The stream which we next cross is the Knag-burn; it forms the eastern boundary of Housesteads. Passing it, we scale the ramparts of this far-famed station. [Sidenote: THE ANCIENT BORCOVICUS.] BORCOVICUS.—‘This’ says Gordon, ‘is unquestionably the most remarkable and magnificent station in the whole island;’ and ‘it is hardly credible what a number of august remains of the Roman grandeur is to be seen here to this day, seeing in every place where one casts his eye there is some curious Roman antiquity to be seen: either the marks of streets and temples in ruins, or inscriptions, broken pillars, statues, and other pieces of sculpture all scattered along the ground.’ Stukely, in the vehemence of his admiration, denominates it ‘the Tadmor of Britain.’ Let not the visitor, however, approach it with expectations too greatly excited. There is very much to admire, but not a great deal to strike the eye at first sight. The altars and sculptured figures which lay in profusion on the ground when Gordon and Stukely were there, have been removed,[100] but the ruins of the place remain as complete and vast as ever. The city is, in a great measure, covered with its own debris, but the excavations which have recently been made, shew us that when they are continued throughout the entire station, the ancient BORCOVICUS will be the Pompeii of Britain. [Sidenote: HOUSESTEADS.] The station of Housesteads contains an area of nearly five acres. 'Half of it hangs on a slope, with a southern aspect: the other, or northern half, is flat, floored with basalt, covers the summit of a lofty ridge, and commands a prospect on the east, south, and west, far away beyond the valley of the Tyne, over blue air-tinted grounds and lofty mountains; and to the north of the Wall, over the vast waste of the forest of Lowes, where indeed, a proud, stupendous solitude frowns o’er the heath.' The Wall forms its northern boundary, and the Vallum, it is probable, came to the support of its southern rampart.[101] It is naturally defended on all sides, except the west. In order duly to protect this side, the gateway seems to have been walled up at an early period, and a triple line of ramparts drawn along it.