A run down the river Thames will take any one who has a day to spare to the isle of Sheppey, where he will be amply rewarded by seeing, on the north side of the island, an exposure of this formation in the cliff laid bare to the height of 200 feet, and which pleasure trip will be amply rewarded by the discovery _in situ_ of the fossil tropical plants, &c., that once flourished in the neighbourhood of our cold and foggy London. “At the entrance of the Thames, the London clay extends on both sides of the river, and is admirably exhibited in the isle of Sheppey, which consists entirely of this stratum. The cliffs on the north side of the island are upwards of 200 feet high, and are cut down vertically by the action of the sea; they have long been celebrated for the remarkable abundance and variety of the organic remains obtained from them, amongst which, perhaps, the most interesting are the fruits, berries, and woody seed-vessels of several hundred species of plants. From the same locality there have also been obtained the remains of upwards of fifty species of fish, and a considerable number of crustaceans, and many other invertebrata; besides some remarkable bones which have been described by Professor Owen, and which indicate the former existence in this island of large serpents, and of such birds as prey upon small reptiles and mammalia. Many of these fossils, especially those of plants, are very difficult to preserve, owing to the great tendency of the iron pyrites, which enter largely into their composition, to effloresce and be destroyed by exposure to the atmosphere.”[115] Passing from the London basin to the Hampshire basin or Barton beds, we shall first give a group of the shells found here; and we wish our readers could look at them as they lie before us in their condition of most exquisite preservation, so exquisite, that those who have seen them have involuntarily and frequently exclaimed, “_But these can’t be fossils!_” I know of no picture-painting of past history so touching, and yet so true, as these lovely specimens of the shells of the pre-Adamite condition of England in all their native simplicity. To those who see in them shells, and only shells, why, in the name of the prophet, give them _figs_, while we again remember Wordsworth’s hero,— “A primrose on the river brim, A yellow primrose was to him, And it was nothing more.” To us they speak a wondrous story, replete with the knowledge that maketh glad the heart of man, because it is purifying, elevating knowledge; and though it does not teach the peculiar truths of theology, and we heartily wish that geology had been allowed to tell only its own tale of Creation—for here, as elsewhere, “Nature, when unadorned, Is then adorned the most”—