The work has been done through contact with its neighbours--not by an occasional rub, but by steady friction, long continued. Each grain of sand, rubbing against and being rubbed by its companion-grains, has been rounded, smoothed, polished, till it has grown into the finished specimen, without any obtrusive points or disagreeable angles remaining. An unpleasant discipline, perhaps; yet, in the case of sand-grains and also of human beings, worth undergoing for the sake of results. Looked upon from a geological point of view, this shape of the sand-grains means merely the wearing and wasting away of substance, with no pretty explanation attached, though with a very definite underlying story of their past history. “No workman ever manufactured a half-worn article, and the stones were all worn.” So wrote Hugh Miller when describing his first boyish experience of toil in a Scotch quarry twenty years earlier. Boy as he then was, his keen eyes noted the stones, “rounded and water-worn, as if they had been tossed in the sea or in the bed of a river for hundreds of years.” Boy as he was, he knew that stones, broken off from larger stones or rocks, have at first their irregular shapes, their corners and jagged points, which can only be worked into smoothness by the action of water. Boy as he was, he realised that these quarry inland stones had once been rubbed and shaped by ocean-waves. He made a mistake in his assertion. Some workmen do manufacture articles, not indeed really half-worn, but with the look of being half-worn though actually new, for mercantile purposes--to pass off the new, as if it were old, when the old has greater value. But it may safely and with confidence be declared that the Divine Architect of Earth and Heaven never so puts forth His mighty power. When we see in Nature a thing _worn_ in appearance we know that it has been worn in reality. In his first day of quarry work Hugh Miller saw more than this. He noted surfaces of sandstone rock, laid bare by blasting, all “ridged and furrowed, like a bank of sand that had been left by the tide an hour before.” He had seen the latter hundreds of times when sailing over shallows near the shore. But here the ridges and furrows were petrified, changeless, and on dry land, where no ocean-waves could reach. No wonder he was puzzled. Such ripple-marked sandstone is far from uncommon. It gives a perfect reproduction of the little sand-ripples or rounded ridges and hollows, often to be found on a sandy shore, either visible through a thin layer of water or left bare after the tide goes down. And it shows us how the sandstone rock must originally have been put together, under water. Soft undulations were made in the wet sand by one high tide, becoming in a measure hardened before the next high tide, and so keeping their shapes, while a fresh supply of sand was dropped upon them, partaking of the same outlines.