I made it my first business, on landing in Aberdeen, to wait on my friend Mr. Longmuir, that I might compare with him a few geological notes, and benefit by his knowledge of the surrounding country. I was, however, unlucky enough to find that he had gone, a few days before, on a journey, from which he had not yet returned; but, through the kindness of Mrs. Longmuir, to whom I took the liberty of introducing myself, I was made free of his stone-room, and held half an hour's conversation with his Scotch fossils of the Chalk. These had been found, as the readers of the _Witness_ must remember from his interesting paper on the subject, on the hill of Dudwick, in the neighborhood of Ellon, and were chiefly impressions--some of them of singular distinctness and beauty--in yellow flint. I saw among them several specimens of the Inoceramus, a thin-shelled, ponderously-hinged conchifer, characteristic of the Cretaceous group, but which has no living representative; with numerous flints, traversed by rough-edged, bifurcated hollows, in which branched sponges had once lain; a well-preserved Pecten; the impressions of spines of Echini of at least two distinct species; and the nicely-marked impression of part of a Cidaris, with the balls on which the sockets of the club-like spines had been fitted existing in the print as spherical moulds, in which shot might be cast, and with the central ligamentary depression, which in the actual fossil exists but as a minute cavity, projecting into the centre of each hollow sphere, like the wooden fusee into the centre of a bomb-shell. This latter cast, fine and sharp as that of a medal taken in sulphur, seems sufficient of itself to establish two distinct points: in the first place, that the siliceous matter of which the flint is composed, though now so hard and rigid, must, in its original condition, have been as impressible as wax softened to receive the stamp of the seal; and, in the next, that though it was thus yielding in its character, it could not have greatly shrunk in the process of hardening. I looked with no little interest on these remains of a Scotch formation now so entirely broken up, that, like those ruined cities of the East which exist but as mere lines of wrought material barring the face of the desert, there has not "been left one stone of it upon another," but of which the fragments, though widely scattered, bear imprinted upon them, like the stamped bricks of Babylon, the story of its original condition, and a record of its _founders_. All Mr. Longmuir's Cretaceous fossils from the hill of Dudwick are of flint,--a substance not easily ground down by the denuding agencies.