226 . Geological Society: Dr. Fitton on the 



markable amongst them is Perna Mulleti. Mya and Panoptea, pro- 

 bably of more than one species, are especially numerous, even close 

 to the very junction of the Wealden : and with these were Area 

 Raulini, Mytilus lanceolatus, Pinna sulcifera, Pecten quinquecostatus, 

 and P. striato-costatus (Goldfuss). 



4. The bed of firm, subferruginous and somewhat calciferous stone 

 which next succeeds, formed, when the author first examined this 

 place (in 1826), the most prominent feature of the cliffs : everything 

 beneath, to a depth of about ten feet, being deeply concealed by 

 ruin. It was now distinctly seen that the bottom of this remarkable 

 bed is not more, at the utmost, than three feet from the top of the 

 Wealden. By its greater firmness it contributes to sustain the cliff, 

 the mass of which it traverses obliquely in rising westward ; and 

 from the base of the projecting land or point of Atherfield it runs 

 out into the sea, declining very gradually, and forming a dangerous 

 reef called Atherfield ledge. Though its average thickness is not 

 more than 2| feet, this bed abounds very remarkably in fossil remains, 

 among which are several of the species figured by M. Leymerie in 

 his memoir on the geology of the Aube, and of those found by Mr. 

 Austen at Peasemarsh, in Surrey. 

 Ostrea (new species). Pecten quinquecostatus. 



Spatangus (three or more species) . striato-costatus. 



Mya mandibula. obliquus {inter stria t us 



Pholadomya acutisulcata (Leym.). Leym.). 



Prevosti (Leym.). Gryphcea sinuata. 



Corbula striatula. Terebratula sella. 



Sphcera corrugata. (three or more other sp.). 



Thetis minor. Orbicula Icevigata (Deshayes). 



Trigonia dcedalea. Natica (Ampullaria) Icevigata 



Fittoni. (Leym.). 



(two new species). Pleurotomaria gigantea. 



Gervillia aviculoides. Nautilus radiatus. 



Pinna sulcifera. Ammonites Deshayesii (Leym.). 



Perna Mulleti. (four or five species) . 



— — alceformis. with many other genera. 



5. Immediately above the stone-bed (4), is a thick mass of nearly 

 uniform clay, with many of the properties of fuller's earth. It is di- 

 vided apparently into two principal strata, each not less than fifteen 

 feet in thickness ; and these seem to be succeeded upwards by other 

 argillaceous beds, which were so much obscured by debris as not 

 to be traceable. The fuller's earth is either of a lavender-blue or of 

 a drab colour ; it contains concretional portions (not seen in situ), 

 almost composed of fossils, including Thetis minor, Rostellaria bica- 

 rinata, with several small univalves. Other masses, also of uncertain 

 place, occur in the fuller's earth, containing numerous Crustacean re- 

 mains, especially of Astacus, of more than one species. Pinna sulci- 

 fera abounds near the bottom of the lower bed, and Ammonites Des- 

 hayesii, with other Ammonites, is frequent. 



§. From the preceding lists, it is evident that an accumulation of 

 fossils, very remarkable for their number and variety, exists at 



