164 UPPER, OR FLINTY CHALK. 



from one common centre, or stem, and surrounded by a spongeous epi- 

 dermis. Their constituent substance is siliceous, being frequently com- 

 posed of agate or chalcedony, and having a loose covering of carbonate of 

 lime. 



An analogous structure is observable in the " sand alcyonia " of 

 Warminster Common, but the latter do not appear to possess the sponge- 

 ous epidermal covering, so strikingly displayed in the former. The only 

 recent zoophyte to which these fossils bear the slightest resemblance, is 

 the " branched sponge from Cape Coast Castle, in Africa," figured by 

 Ellis in the Philosophical T^-ansactions, Vol. 55, Tab. 11, fig. F ; but the 

 dissimilarity between them is too great, to admit of the supposition that 

 they belong to the same genus. 



Localities. Upper chalk, near Lewes and Brighton. 



13. The epidermis of a ramose zoophyte attached to a flint. 



The surface is covered with minute openings regularly disposed, and 

 when viewed through a lens, the intermediate substance is observed to be 

 finely punctated. 



This specimen belongs to a genus formed by Mr. Konig, for the recep- 

 tion of those fossil zoophytes that possess symmetrical openings, either 

 round, or disposed in meshes. 



Localities. Ploughed lands on the Downs. 



1 4. Spongus * Townsetuli. Tab. xv. fig. 9. 



Body cyathiform, containing a conical cavity ; substance spongeous ; 

 stirps fixed by radical processes. 



These are the cup-like corals, or sponges, so accurately described by 

 the late Eev. J. Townsend, of Pewsey-j- ; and by Mr. Parkinson:}:, in his 

 celebrated work on the organic remains of a former world. The usual 

 form of the specimens is that of fig. 9. Tab. xv. 



* " Spongus corpus multiforme, epidermide porosa tectum, protuberantiis interdum conicis, 

 oculiferis. — It approaches the genus sjjongia, from which it differs in being invested with an 

 epidermis, and in having had the power of contraction ; the epidermis as well as the oculi, are 

 oi'ten destroyed in the process of mineralization." Extract of a letter from Chas. Konig, Esc^. 

 of the British Museum, to the author. 



f Character of Moses, 2 vols. 4to. 1813. 



+ 0?-ganic Remains, Vol. ii. pp. 125, 126, 



