1848.] LONSDALE ON FOSSIL ZOOPHYTES. 55 



wooded cone of about 40 feet high was situated in the crater ; this 

 was dissipated in 181 2, and since that time none has been visible ; the 

 depth of the water is not known ; the walls of the crater are so steep, 

 that it is very difficult and dangerous of access. 



6. Notes on Fossil Zoophytes /bww^ in the Deposits described by 

 Dr. Fitton in his Memoir entitled *' A Stratigraphical Ac- 

 count of the Section from Atherfield to Rocken End *." 

 By William Lonsdale, F.G.S. 



See Plates IV. and V, 



The fossil to be first noticed is apparently not included in the 

 stratigraphical lists or table published in the Quarterly Journal of 

 the Geological Society of London. It consists of small amorphous 

 masses attached at the base, from which in one instance extended a 

 thin layer (PL IV. fig. 1) ; and it is composed chiefly of irregularly ar- 

 ranged ridges with adjacent hollows, the whole surface being indented 

 by small pits and furrows, some of which are shallow, but others 

 penetrate to a greater depth (fig. 2) ; the intermediate apparently 

 solid portions have also minute pores (fig. 2), the terminations, it 

 is presumed, of similar openings detectable in transparent slices 

 of the interior and even in opake sections, and which cannot be 

 regarded either as distinct tubuli or as mouths of cells. Internally 

 the fossil presents numerous lacunae (fig. 3), the downwards exten- 

 sion of the surface-pits. Some of them are circular, but they are more 

 often unequal in shape and size, and occasionally blended together ; 

 they have no direct boundary, and frequently exhibit a greater or less 

 degree of cloudiness, due apparently to a structural substratum. In 

 some portions of an intersection they abound, while in other parts 

 they are few in number or wanting. The intervals consist of an 

 opake-white matter, not reducible to any distinct texture by the 

 powers used in the examination (a Codrington lens and a Hooker's 

 microscope) ; but it occasionally incloses an irregular network, 

 formed of very minute fibres, and not unlike in texture the reticula- 

 tion of horny sponges (fig. 4) . This structure is also exposed in some 

 of the lacunae. The opake intervals are penetrated by the micro- 

 scopic pores before-mentioned. These leading component parts 

 prove, that nothing strictly identical with the abdominal cavities of 

 Anthozoa and Bryozoa is recognisable in the Atherfield fossil ; while 

 they justify its being assigned to the class Amorphozoa. 



The materials of which the solid portions of recent sponges are 

 constructed, and their modes of combination, are known to vary 



* Read January 22, 184.5. Published in the Quarterly Journal, August 1847, 

 vol. iii. p. 289 et seq. At p. 318, a ** Cellepora (same as at Farringdon)" is men- 

 tioned among the organic remains from " Sandown Bay and coast near Shanklin." 

 No specimen of that fossil was included in the collections submitted to examina- 

 tion ; and it is not possible that those about to be described could have been as- 

 signed to the genus Cellepora. 



