6. Approaching Perth by the Midland Junction, the geologist cannot fail to be arrested by the vast accumulations of sand and gravel, which everywhere present themselves, sometimes in the deep cuttings and railway sections; sometimes in the shape of rounded hillocks or long narrow ridges; and at other places as extended plateaux or sea-margins of different elevations. Along the whole western and southern slopes that overhang the city, these objects give a pleasing variety to the landscape, and form interesting subjects of speculation as to their origin, doubtless the gathered wreck of all the rocks we have been contemplating; for after a careful examination of their contents the conclusion cannot be avoided, that with much of the spoil of the primary rocks, we have here the detrital waste of the entire old red sandstone series. The Carpow cutting, in Strathearn near Newburgh, contains large rounded masses of all the varieties, with their peculiar ichthyolites; the gray, red, and yellow deposit that prevails in Fifeshire, and one solitary patch of which still exists _in situ_, near the Kirk of Dron, as if on purpose to mark its ancient and more extended boundaries. Nodules and bowlders of the cornstone are likewise abundant. In the vicinity of Perth, the waste of the yellow sandstone is to be found, unmixed in several spots, consisting of thick beds of fine argillaceous sand. Similar masses of gravelly debris are spread over the middle-basin of the Earn, from Forteviot to Muthil. The Scottish Central cleaves its way for ten miles through scarcely any other material. The dreary monotony of these endless hillocks, around Auchterarder and Blackford, is relieved in part by the fine undulating grassy braes of the Ochils, and the richly-wooded rising grounds skirting the left bank of the river. The geologist’s eye wanders eastward, through the district occupied by the lower basin of the Tay, where the whole was one great estuary or strait, and these the shoals covered by the ancient waters. The eastern shores, from Wormit-bay to Leuchars, are accordingly characterized by vast accumulations of sand and gravel, originating in the same causes and deposited at the same period.