F. 2.—­Of all this swarming life no trace now remains.  So entirely did it cease to be that the very names of the stations have left no shadow of memories on their sites.  Luguvallum at the one end, and Pons Aelii at the other, have revived into importance as Carlisle and Newcastle,[288] but of the rest few indeed remain save as solitary ruins on the bare Northumbrian fells tenanted only by the flock and the curlew.  But this very solitude in which their names have perished has preserved to us the means of recovering them.  Thanks to it there is no part of Britain so rich in Roman remains and Roman inscriptions.  At no fewer than twelve of these “stations” such have been already found relating to troops whom we know from the ‘Notitia’ to have been quartered at given spots per lineam valli.  A Dacian cohort (for example) has thus left its mark at Birdoswald, and an Asturian at Chesters, thereby stamping these sites as respectively the Amboglanna and Cilurnum, whose Dacian and Asturian garrisons the ‘Notitia’ records.  The old walls of Cilurnum, moreover, are still clothed with a pretty little Pyrenaean creeper, Erinus Hispanicus, which these Asturian exiles must have brought with them as a memorial of their far-off home.

F. 3.—­Many such small but vivid touches of the past meet those who visit the Wall.  At “King Arthur’s Well,” for example, near Thirlwall, the tiny chives growing in the crevices of the rock are presumably descendants of those acclimatized there by Roman gastronomy.  At Borcovicus ("House-steads”) the wheel-ruts still score the pavement; at Cilurnum the hypocaust of the bath is still blackened with smoke, and at various points the decay of Roman prestige is testified to by the walling up of one half or the other in the wide double gates which originally facilitated the sorties of the garrisons.

F. 4.—­The same decay is probably the key to the problem of the “Vallum,” that standing crux to all archaeological students of the Wall.  Along the whole line this mysterious earthwork keeps company with the Wall on the south, sometimes in close contact, sometimes nearly a mile distant.  It has been diversely explained as an earlier British work, as put up by the Romans to cover the fatigue-parties engaged in building the Wall, and as a later erection intended to defend the garrison against attacks from the rear.  Each of these views has been keenly debated; the last having the support of the late Dr. Bruce, the highest of all authorities on the mural antiquities.  And excavations, even the very latest, have produced results which are claimed by each of the rival theories.[289]