T he Royal Fern ( Osmunda regalis , Linn.) is the noblest and most striking of our British ferns. The tuft of fronds under favourable circumstances attains a height of nearly 12 feet, and the erect stem is sometimes more than 2 feet long. The stem is perennial, growing in tufts, formed by the repeated dichotomous division of the terminal bud; the whole is matted together by a large mass of adventitious wiry roots. The different stems are stout and firm, and densely covered with the permanent bases of the petioles. It is found in wet, springy, or boggy places all over Britain, and is indeed generally distributed over the northern temperate zone. With one other genus, Todea , it forms a small but well-marked natural group of ferns, the Osmundaceæ . I have determined the existence of Osmunda regalis in the Norwich Forest-bed from large specimens collected by the Rev. J. Gunn. It is common in the newer submerged forests, having maintained its ground through all the changes that have taken place. Three closely allied forms have been found in the later Tertiary strata; the oldest was obtained from a bed at the base of the Miocene period. I have now to add a fourth from the Lower Eocene at Herne Bay. This species is based upon a portion of a stem in the collection of George Dowker, Esq., F.G.S. It is somewhat unequally weathered and water-worn, one of its sides being rubbed nearer to the centre than the other. The whole of the