The next defile is Caw-gap; some ruined cottages, formed of Wall-stones, stand in it. The extreme jealousy with which the Romans defended an exposed situation is well shewn here. The fosse, which guards the pass through the low ground, is discontinued on the western side as soon as the Wall attains a sufficient elevation, but upon the the ground drooping, though only for the space of a few yards, it re-appears for that short distance. A road runs through this pass to the north, which soon becomes a mere track. It passes a solitary house, called Burn Deviot, nearly due north from the gap, which was long the resort of smugglers and sheep-stealers. The memory of its last tenants, Nell Nichol and her two daughters, who were a pest to the country, is still fresh in the district. Though many years have elapsed since any one occupied the dwelling, lights are said often to be seen at the windows at night, visible tokens of the presence of the spirits of the murdered children of Nell’s daughters. [Sidenote: CAWFIELDS CRAGS.] The crags along which we soon find ourselves to be proceeding, possess a perpendicular elevation of nearly five hundred feet above the plains below. Passing another small gap, called the Thorny Doors, we come to a tract of Wall in an excellent state of preservation. The lower courses have lately been freed from the rubbish which for centuries has covered them, and the fallen stones replaced in their proper order. The whole face of the Wall has a remarkably fresh appearance, and nowhere can the tooling of the stones be examined with more advantage. Amongst the fallen stones, one was lately found which furnishes us with additional evidence, that the twentieth legion was engaged in the erection of this part of the Wall. It [Illustration: alt=Mural Stone, Leg. XX. V.V.] is preserved amongst the antiquities at Chesters, and is represented in the adjoining cut. This sculpture cannot have been derived from the Vallum, in the construction of which, in the time of Hadrian, the twentieth legion is acknowledged to have been employed; for the Vallum is here distant more than three hundred yards from the Wall. The reader will of course perceive the bearing which this fact has upon the question of the contemporaneous origin of the two structures, and the construction of the Wall, as well as the Vallum, by Hadrian. While the antiquary is eagerly scrutinizing indentations in stones which were chiselled sixteen centuries ago, his eye will occasionally rest upon the memorials of an antiquity so indefinite as to throw into the shade even his primeval records. Lepidodendra, and other fossils of the mill-stone-grit and coal series, are of occasional occurrence. Who shall tell when these giant plants flourished, how they were enveloped in their sandy bed, and how hardened into the flinty stone made use of by the Roman soldiers? Imagination reels at the questions suggested. [Sidenote: PILGRIMS'-GAP.]