No currents or sudden freshets carrying hard materials with them, even moving along straight paths down hill-sides or mountain-slopes, have ever been known to draw any such lines. They could be made only by some instrument held fast as in a vice by the moving power. Something of the kind is occasionally produced by the drag of a wheel grating over rocks covered with loose materials. It has been said that grounded ice or icebergs floating along a rocky shore might produce similar marks; but they will chiefly be at the level of high-water mark, and, if grounded, they will trend in various directions, owing to the rocking or rotating movement of the iceberg. It has also been urged, that, without admitting any general glacier-period, icebergs and floating ice from more northern latitudes might account for the extensive transportation of the loose materials scattered in a continuous sheet over a large portion of the globe. There can be no doubt that an immense amount of _debris_ of all sorts is carried to great distances by floating ice; where their presence is due to this cause, however, they are everywhere stranded along the shore or dropped to the sea-bottom. Large boulders are frequently left by the ice along the New-England coast, and we shall trace them hereafter among the sand-dunes of Cape Cod. But before it can be admitted that the drift-phenomena, and the polished and engraved surfaces with which they are everywhere intimately associated, are owing to floating ice or icebergs, it must be shown that all these appearances have been produced by some agency moving from the sea-board towards the land, and extending up to the very summits of the mountains, or else that all the countries exhibiting glacial phenomena have been sunk below the ocean to the greatest height at which glacier-marks are found, and have since gradually emerged to their present level. Now, though geologists are lavish of immersions when something is to be accounted for which they cannot otherwise explain, and a fresh baptism of old Mother Earth is made to wash away many obstacles to scientific theories, yet the common sense of the world will hardly admit the latter assumption without positive proof, and all the evidence of the kind we have, at the period under consideration, indicates only a comparatively slight change of relative level between sea and land within a narrow belt along the shores; and even this is shown to be posterior, not anterior, to the glacial phenomena. As to the supposition that the motion proceeded from the sea towards the land, all the facts are against it, since the whole trend of these phenomena is from inland centres toward the shore, instead of being from the coast upward.