They form here the sole remains of dykes of an earthy trap, which, though at one time in a state of such high fusion that they converted the portions of soft sandstone in immediate contact with them into the consistence of quartz rock, have long since mouldered away, leaving but the hollow rectilinear rents which they had occupied, surmounted by the indurated walls which they had baked. Some of the most curious appearances, however, connected with the sandstone, though they occur chiefly in an upper bed, are exhibited by what seem fields of petrified mushrooms, of a gigantic size, that spread out in some places for hundreds of yards under the high-water level. These apparent mushrooms stand on thick squat stems, from a foot to eighteen inches in height; the heads are round like those of toad-stools, and vary from one foot to nearly two yards in diameter. In some specimens we find two heads joined together in a form resembling a squat figure of _eight_, of what printers term the Egyptian type, or, to borrow the illustration of M'Culloch, "like the ancient military projectile known by the name of double-headed shot;" in other specimens three heads have coalesced in a trefoil shape, or rather in a shape like that of an ace of clubs divested of the stem. By much the greater number, however, are spherical. They are composed of concretionary masses, consolidated, like the walls of the dykes, though under some different process, into a hard siliceous stone, that has resisted those disintegrating influences of the weather and the surf, under which the yielding matrix in which they were embedded has worn from around them. Here and there we find them lying detached on the beach, like huge shot, compared with which the greenstone balls of Mons Meg are but marbles for children to play with; in other cases they project from the mural front of rampart-like precipices, as if they had been showered into them by the ordnance of some besieging battery, and had stuck fast in the mason-work. Abbotsford has been described as a romance in stone and lime; we have here, on the shores of Laig, what seems a wild but agreeable tale, of the extravagant cast of "Christabel," or the "Rhyme of the Ancient Mariner," fretted into sandstone. But by far the most curious part of the story remains to be told.