Near Willingdon, in Sussex (Geol. S. E. p. 172), a bed of sand, immediately beneath the Galt, contains a layer of water-worn fragments of stems and branches, of small size; they are generally perforated by Gastrochænce, and the cavities formed by these depredators are filled with particles of green chlorite sand. The structure of this wood is represented in Plate V. fig. 3a a transverse, and 3b a vertical section, viewed by reflected light; in 3b the vessels are dotted with two parallel longitudinal rows of very minute glands, arranged alternately, as in the Araucariæ; a fragment of one of the medullary rays is seen near the middle of the specimen.
In this deposit of coniferous wood, two or more fruits apparently referable to Zamiæ have been discovered; one specimen, five and a half inches long, and of an elongated cylindrical form, covered with rhomboidal eminences, I have figured and described as Zamites Sussexiensis.[148]
[148] Geol. Proc. 1843.
Lign. 58. Fragment of Coniferous Wood in Flint.
From a wall in Lewes Priory,
The White Chalk of England has afforded but few traces of plants of this family. Fragments of coniferous wood are, however, occasionally found in the state of carbonaceous, or reddish brown friable masses, and when this substance is removed, the surface of the chalk is seen to be marked with impressions of ligneous fibres; sometimes the surface is studded over with little pyriform eminences, which are cretaceous casts of perforations made by insects in the wood. These specimens, when all traces of the wood are absent, are very puzzling to those who are not aware of their origin.
Occasionally silicified fragments of wood are found imbedded in flint. I have an interesting specimen of this kind obtained from a wall in Lewes Priory ([Lign. 58]), and though it must have been exposed to the influence of the weather for nearly eight centuries, its surface still exhibits coniferous structure.
WOOD IN FLINT.
Tertiary Coniferous Wood.—The Tertiary formations in some localities abound in coniferous plants and trees, which, in the Paris basin, are associated with bones of mammalia; several species of pine (Pinus) and of yew (Taxus) from those deposits are described by M. Brongniart. I have collected fossils of this kind from the London Clay of the Isle of Sheppey, Bracklesham Bay, and Bognor in Sussex, and Alum Bay, in the Isle of Wight; and from the plastic clay at Newhaven.