Unless when deeply buried beneath drift-sand and clay, trappean regions usually possess scenery of a marked kind. A green undulating country stretches out as far as the eye can reach, diversified here and there with bold abrupt crags and conical hills. The lower grounds show in the winter season their rich brown loam, that waxes green as the spring comes on, and ere summer's close spreads out its heavy crops of golden grain. The higher ridges are for the most part thickly wooded, yet the soil is often scanty, and, among the white stems of the beech, or the matted roots of the fir and the elm, we may not unfrequently see the rock protruding its lichen-crusted face, mottled with mosses and liverworts, while some sluggish runnel collects in stagnant pools, or trickles over the blocks with a thick green scum. Sometimes the hill has never been planted, but stands up now, as it has done for centuries; its western face craggy and precipitous, with bushes of sloe-thorn and furze, and stray saplings of mountain-ash clinging to the crevices, while its eastern slope sinks down into the rolling country around with a green lumpy surface, through which, at many a point, the grey time-stained rock may be seen. The whole district suggests to the fancy a billowy sea, and, as one casts his eye from some commanding hill-top athwart the wide expanse of hill and valley, sweeping away in endless undulations, he is apt to bethink him of some day far back in the past, when the verdant landscape around lay barren and desolate, while the solid earth rocked and heaved in vast ground-swells like a wide tempested ocean. Such is the aspect presented by some of the more trappean regions of Scotland. But the origin of this kind of scenery must be ascribed to the effects of denuding currents in scooping out the softer strata into clefts and valleys, and leaving the harder trap-rocks in prominent relief, rather than to any great inequality of surface produced by the eruption of igneous matter; for we shall find that the throwing out of sheets of lava and showers of volcanic ashes was often a very quiet process after all.