The Wall, when it does not fall in with the northern wall of a station, usually comes up to the northern cheek of its eastern and western gateways. The Vallum, in like manner, usually approaches close to the southern wall of the station, or comes up to the defence of the southern side of the eastern and western portals. Examples of these arrangements are given in Plate II. At least three of the stations, it must, however, be observed, are quite detached from both lines of fortification, being situated to the south of them. They may have been members of Agricola’s chain of forts. Probably all the stations have, on their erection, been provided, after the usual method of Roman castrametation, with four gateways; in several instances one or more of these portals have been walled up at an early period, in consequence, probably, of some natural weakness in the situation. Narrow streets, intersecting each other at right angles, occupy the interior of the stations, and abundant ruins, outside the walls, indicate the fact that extensive suburbs have, in every instance, been required for the accommodation of the camp-followers. [Sidenote: THE FERTILITY OF THE STATIONS.] In selecting a spot for a station, care has been taken that an abundant supply of water should be at hand. The springs, rivulets, wells, and aqueducts, whence they procured the needful fluid, are still, in many places, to be traced; and never did water more limpid, more sparkling, more invigorating, lave the lips of man, than that which flows from these sources. For the most part, the stations—cities which for centuries were the abodes of busy men, and which resounded with the hum of multitudes, and the clash of arms,—now present a scene of utter desolation. The wayfarer may pass through them without knowing it; the streets are levelled, the temples are overthrown, and the sons and daughters of Italy, Mauritania, and Spain, whose adopted homes they were, no longer encounter him. The sheep, depasturing the grass-grown ruins, look listlessly upon the passer-by, and the curlew, wheeling above his head, screams as at the presence of an intruder. Whether, or not, sites naturally fertile were chosen for the stations does not appear; but certain it is, that they are now for the most part coated with a sward more green and more luxuriant than that which covers the contiguous grounds. Centuries of occupation have given them a degree of fertility which, probably, they will never lose.[25] One can scarcely turn up the soil without meeting, not only with fragments of Roman pottery and other imperishable articles, but with the bones of oxen, the tusks of boars, the horns of deer, and other animal remains. The debris of some of these cities is considered to be more valuable for farm purposes, than the recent produce of the fold-yard, and is used as such. [Sidenote: THE NAMES OF THE STATIONS.]