"Vol. 69.] PROF. A. C. SEWARD ON WEALDEN FLORAS. 85- 



7. A Contribution to our Knowledge of "Weal den Floras, ivitli 

 especial reference to a Collection of Plants from Sussex. 

 By Albert Charles Seward, F.B.S., F.Gr.S., Professor of 

 Botany in the University of Cambridge. (Read November 

 6th, 1*912.) 



[Plates XI-XIV.] 



I. Introductory Remarks. 



In November of last year (1911) Mr. Charles Dawson, F.S.A., 

 F.G.S., submitted to me for examination a small collection of plants 

 obtained by him, with the able assistance of Father Teilhard do 

 Chardin and Father Felix Pelletier, from the Wealden Beds of 

 Sussex, for the most "part from the neighbourhood of Fairlight.. 

 Several of the specimens, although specifically identical with, 

 previously recorded types, are better preserved or larger than* 

 any hitherto found, and furnish new facts of importance. The 

 collection includes also several new species. In accordance with. 

 Mr. Dawson's wish, the specimens have been handed to Dr. Smith 

 Woodward as a gift to the Geological Department of the British 

 Museum (Natural History). With the exception of the example 

 of Sagenojrteris mantelli shown in PI. XI, fig. 3, which is from the 

 Ashdown Sands, the fossils in the Dawson Collection were obtained 

 from the Fairlight Clay. 



In the descriptive section of this paper are included a few speci- 

 mens from the liufford Collection (collected at Ecclesbourne, near 

 Hastings), acquired by the Museum subsequent to the publication 

 of the Catalogue of Wealden Plants. 1 



II. Description of the Specimens. 



EQUISETALES. 

 Equisetites lyelli (Manfc.). (PI. XI, figs. 1 a & 1 h.) 



(Near Fairlight, Wadhurst Clay; Dawson Collection.) 

 1833. Mantell, ' Geology of the South-East of England ' p. 245 & figs. 1-3. 



The specimen represented in PI. XI, fig. 1 a, though smaller 

 than some previously figured from the Wealden Beds of Sussex, 

 exhibits certain features worthy of notice. The incomplete inter- 

 node has a length of 4 cm. and a breadth of 7 mm. A portion of 

 a leaf-sheath is seen at the upper end with linear lanceolate teeth 

 (fig. 1 b) showing a ragged carbonized border, which may be the 

 remains of torn, transversely elongated cells, such as form the com- 

 missural tissue in the leaf-sheaths of recent species. On the linear 

 divisions of the sheath and on the free acuminate teeth the outlines 



1 Seward (94) & (95). These numerals in parentheses refer to the Eiblio- 

 graphy, § IV, pp. 112-15. 



