The locality bearing marks of military works near Dunblane is called Laigh Hill in the Ordnance map, though it is composed of several ridges and eminences. Curiously, however, the configuration of the ground is not delineated, though on the scale of six inches to the mile, but the neighbouring part all round is traced minutely. The situation is one of great natural strength, as it is surrounded by the loop of the river Allan, and by a small brook that runs into it opposite Mr. Wilson's woollen factory. The line of the Caledonian railway passes through it from south to north, and also divides one of the camp sites from the other, so that one may be called the east camp and the other the west one. From the appearance of the neighbouring rising grounds, which are all rounded and smooth, it is not unlikely that Laigh Hill, instead of being an aggregate of mounds, was at one time a single hill, if not a double one. With this idea in mind, it may be conceived that these works have been excavated out of the natural hills, and not erected, and therefore that the original rounded eminence of Laigh Hill has disappeared. This mode of constructing fortifications is visible in several old British strongholds, as at Sarum, Camelet, and Caterthun, where the aggers may be of such vast size as one hundred feet in width at the base and twenty-five feet at the top, and as many high. The supposed west camp is of an oval shape, and is contained in the loop of the river Allan; the northern face of its plateau rests upon the precipice overhanging the water.