Neither the leaves nor the fruit are known: a cone found in the Dirt-bed of Portland, and attributed to these plants, appears to belong to the coniferæ of the petrified forest. Examples of Mantelliæ have been found in the quarry of Portland-stone at Swindon, Wilts. [Sidenote: CLATHRARIA LYELLII.] [Illustration: Lign. 52. Clathraria Lyellii. _Wealden._ A branched example of the inner axis: the original 3-1/2 feet high.] Clathraria[133] Lyellii. _Lign. 52-57._--The fossil plants to which I would next direct attention were first discovered by me in the Wealden strata of Sussex, in 1820, and were figured and described under the name they still bear, in my Fossils of Tilgate Forest, in 1827. The specimens figured in that work are the most illustrative hitherto discovered, with but one exception.[134] [133] EC C lathraria, _i.e._ _lattice stem_, from the scars left by the petioles. [134] They are now in the British Museum; see Petrifactions, p. 45. _Room_ I. _Case_ E. From the imperfect state of the remains of these plants, the structure and affinities of the originals were very ambiguous, and the fossils have been placed by some eminent botanists with the Liliaceæ, and by others with the Asphodeleæ; their true botanical position is doubtless with the Cycadaceæ; for in some points they resemble the Zamiæ, in others the Cycadeæ. The stem of the Clathraria is composed of a solid internal axis, the surface of which is covered with reticulated fibres; the large branched specimen of this part, figured in _Lign. 52_, is the finest example hitherto obtained: it was discovered, with bones of the Iguanodon, in a quarry near Cuckfield, Sussex, in 1820. The axis is invested with a very thick false-bark, formed of the consolidated bases of the leaf-stalks, the insertions of which are rhomboidal and transverse. The outer surface of the bark is consequently marked with elevated lozenge-shaped cicatrices (_Lign. 53_), separated from each other by a marginal furrow, which is surrounded by a parallel ridge or band of a fibrous structure. [Illustration: Lign. 53. Clathraria Lyellii. 1/4 _nat._ A stem, with rhomboidal transverse scars, left by the petioles; broken transversely and separated, to show the internal axis at _a_, which, if the pieces were united, would be received in the cavity below the depression, or cicatrix, on the middle of the upper portion, _b_, was probably the situation of a resinous secretion, like the dragon-blood in the Dracæna.] The cortical zone is generally converted into a cylinder of stone, which in some examples separates from the axis. In a beautiful specimen of this kind, _Lign. 54_, the axis projects and is surrounded by the false-bark.