'262 PLASTIC CLAY FORMATION. 



The organic remains found in these deposits are the following : 



1. Wood. 



A small block of wood, with the ligneous structure well preserved, has 

 been discovered in the sand of the Diluvium (No. 11.) 



2. Impressions and remains of leaves, Tab. viii. figs. 1, 2, 3, 4. 

 : Brit. Mill. tab. 500. 



The specimens figured in Tab. viii. and in Mr. Sowerby's Brit. Min. 

 were collected from the red marl (No. 7); but although considerable 

 dihgence has been used to add to their number, our researches have been 

 unsuccessful, nor can we discover the precise spot from whence they were 

 taken. They are pecuUarly interesting, as they aiford an example of 

 leaves and shells imbedded in the same stone ; an association but rarely 

 observed. 



The impressions in figs. 1, and 4, are thought to bear some resemblance 

 to the larger foliage of Platanus orientalis. This opinion may probably be 

 correct so far as regards the genus ; but the characters of the leaves appear 

 to be too imperfectly developed to admit of the species being identified. 



Figs. % and 3, differ in some respects from those above described. 



The upper beds of the " Calcaire marin grossier" of France, also 

 contain vegetal impressions ; but those represented in the " Essai sur la 

 Geographic Mineralogique," PI. 2. fig. 1. do not correspond with the 

 fossils under consideration. The French specimens are supposed to 

 belong to a species oi Neriiim; however this may be, it is obvious, that, 

 like those of Newhaven, they cannot have belonged to any marine plant, 

 although they are now imbedded in the midst of testaceous remains 

 decidedly of marine origin*. 



3. Mr. Webster mentions that H. Warburton, Esq. discovered in 

 the marl at Newhaven, leaves precisely similar to those figured by 



pose ; and no traces of it occur in any other part of the adjacent coast. The encroachments of 

 the sea at Brighton are well known to have been very extensive within the few last centuries : 

 is it probable that a bed of surturhrand formerly existed in the strata that have been swept 

 away? or was the layer at Castle Hill, at that period, sufficiently extensive? was it washed 

 from the opposite coast of France ? or from Alum bay, in the Isle of Wight ? 

 * Essai Min. Geograjik. :p. 126. 



