CHAPTER XI. Geological Physiognomy.--Scenery of the Primary Formations; Gneiss, Mica Schist, Quartz Rock.--Of the Secondary; the Chalk Formations, the Oolite, the New Red Sandstone, the Coal Measures.--Scenery in the Neighborhood of Edinburgh.--Aspect of the Trap Rocks.--The Disturbing and Denuding Agencies.--Distinctive Features of the Old Red Sandstone.--Of the Great Conglomerate.--Of the Ichthyolite Beds.--The Burn of Eathie.--The Upper Old Red Sandstones.--Scene in Moray. Physiognomy is no idle or doubtful science in connection with Geology. The physiognomy of a country indicates, almost invariably, its geological character. There is scarce a rock among the more ancient groups that does not affect its peculiar form of hill and valley. Each has its style of landscape; and as the vegetation of a district depends often on the nature of the underlying deposits, not only are the main outlines regulated by the mineralogy of the formations which they define, but also in many cases the manner in which these outlines are filled up. The coloring of the landscape is well nigh as intimately connected with its Geology as the drawing. The traveller passes through a mountainous region of gneiss. The hills, which, though bulky, are shapeless, raise their huge backs so high over the brown, dreary moors, which, unvaried by precipice or ravine, stretch away for miles from their feet, that even amid the heats of midsummer the snow gleams in streaks and patches from their summits. And yet so vast is their extent of base, and their tops so truncated, that they seem but half-finished hills notwithstanding--hills interdicted somehow in the forming, and the work stopped ere the upper stories had been added. He pursues his journey, and enters a district of micaceous schist. The hills are no longer truncated, or the t moors unbroken; the heavy ground-swell of the former landscape has become a tempestuous sea, agitated by powerful winds and conflicting tides. The picturesque and somewhat fantastic outline is composed of high, sharp peaks, bold, craggy domes, steep, broken acclivities, and deeply serrated ridges; and the higher hills seem as if set round with a framework of props and buttresses, that stretch out on every side like the roots of an ancient oak. He passes on, and the landscape varies; the surrounding hills, though lofty, pyramidal, and abrupt, are less rugged than before; and the ravines, though still deep and narrow, are walled by ridges no longer serrated and angular, but comparatively rectilinear and smooth. But the vegetation is even more scanty than formerly; the steeper slopes are covered with streams of debris, on which scarce a moss or lichen finds root; and the conoidal hills, bare of soil from their summits half way down, seem so many naked skeletons, that speak of the decay and death of nature. All is solitude and sterility. The territory is one of Quartz rock. Still the traveller passes on: