Passing higher up the geological series, fertile fern fronds with spore-capsules and spores practically identical with those of Osmunda have been found in the Jurassic plant-beds of Yorkshire and in rocks of approximately the same age in many parts of the world. From Jurassic strata in New Zealand a petrified fern-stem has been described (_Osmundites Dunlopi_), almost identical in structure with the surviving species. Cretaceous and Tertiary examples of similar ferns might be quoted; but enough has been said to establish the claim of the Royal Fern and other members of the Osmunda-family to an ancestry which possibly extends even farther back than that of any other existing family of Ferns. [Illustration: Fig. 10. _Gleichenia dicarpa_ Br. (1/2 nat. size.)] A brief reference may be made to another fern now represented by several species widely disseminated in tropical and sub-tropical countries. The genus Gleichenia occurs abundantly in the warmer regions of both the Old and New World. The fronds may usually be recognised by their habit of growth (Fig. 10); in several species the main axis is repeatedly forked and a small bud between the divergent branches of the forks forms a characteristic feature. The leaflets are either long and narrow like the teeth of a comb or short and bluntly rounded. Moreover the anatomy of the creeping stem affords a ready means of identification. We have satisfactory evidence of the occurrence of Gleichenia in European floras during both the Jurassic and Cretaceous periods. Numerous fragments of plants were obtained some years ago, not far from Brussels, from the Wealden strata in which the famous skeletons of Iguanodon were discovered. Visitors to the Natural History Museum in Brussels are no doubt familiar with the skeletons of this enormous herbivorous animal: in the same gallery are exhibited the remains of the fossil plants from the Iguanodon beds. Some of these fragments are pieces of fern fronds identical in form with those of existing Gleichenias. The microscopical examination of some exceptionally well preserved fragments of Wealden stems discovered by Prof. Bommer of Brussels enabled him to recognise the Gleichenia type of structure and thus to confirm the inconclusive evidence furnished by fragmentary leaves. The most interesting records in regard to the former occurrence of Gleichenia in Northern Europe we owe to the late Oswald Heer of Zurich, who has described many examples of Gleichenia fronds from rocks of Lower Cretaceous age in Disco Island on the west coast of Greenland in latitude 70° N. The same type of fern is recorded also from upper Jurassic beds in the north-east of Scotland, in the Wealden rocks of Sussex, as well as from other European localities. It is clear that the Gleichenia-family, no longer represented in north temperate floras, was in the Jurassic period, and especially in the early days of the Cretaceous period, widely spread in Europe, extending well within the Arctic circle.