Geological Society of London. 45 



Bellerophon Ramseyensis and solvenais. 



Palasterina Ramseyensis. 



Dendrocrinus Cambrensis. 



Ctenodonta Meiiapiensis and Cambrensis. 



Raleearca Hopkinsoni and oboloidea. 



Glyptarca (g. n.) primceva and Lobleyi. 



Davidia (g. n.) oniata din^ plana. 



Modiolopsis Ramseyoisis, Homfrayi, solvensis, and Cambrensis. 

 He also noticed the occurrence in the deposit of Lingulella Davisii, M'Coy, Lingula 

 petalon, Hicks, Obolella plicata, Hicks, Orthis Carausii, Salt., and Menapice, Hicks, 

 and Eophyton explanatus, Hicks. 



Discussion. — Mr. Lobley commented on the importance of the discovery of so many 

 well-marked species of Lamellibranchiata in beds of an earlier date than those in 

 which their presence had previously been known. 



Mr. H. "Woodward agreed in regarding the Neseurelus and other fossils exhibited 

 by the author as new. 



Mr. Hopkinson remarked on the similarity of the faunas of the Tremadoc and 

 Arenig rocks to those of the Potsdam and Quebec rocks of America. "With regard to 

 the connexion between the Arenig and Llandeilo beds, he mentioned that but one or 

 two species of Graptolites passed from one to the other. It was, however, between 

 the Tremadoc and Arenig rocks, if anywhere, that there appeared to be a distinct 

 break in the series, 



2, " On the Phosphatic Nodules of the Cretaceous Eock of Cambridgeshire." By 

 the Rev. 0. Fisher, M.A., F.G.S. 



The author stated that this paper was founded upon one read by him before the 

 Society in May last, but subsequently withdrawn, in consequence of his obtaining 

 information which necessitated a change of opinion upon certain points. The new 

 portion related chiefly to those nodules which had been regarded as belonging to 

 Forospongia or Scyphia, the fenestrated structure shown in sections of which the- 

 author now identified with the structure of Ventriculites, as described by Mr. Toulmin: 

 Smith, the whole arrangement, and especially the presence of an octahedral figure- 

 at the nodes where the fibres of the framework intersect one another, being in 

 favour of this determination. The author described the peculiarities of these octa- 

 hedra, and dwelt particularly upon the fact that these sections of phosphatic nodules 

 showed clearly that the fibres are really tubular, and not, as Toulmin Smith supposed, 

 solid. 



3. " On the "Ventriculitidse of the Cambridge Upper Greensand." By W. Johnson 

 SoUas, Esq., Associate of the Royal School of Mines, London. Communicated by 

 the Rev. T. G. Bonney, M.A., F.G.S. 



A collection of supposed sponges found in the Cambridge Upper Greensand had 

 been in part referred to the genera Scyphia and Forospongia, and in part left uniden- 

 tified. An examination of sections of these forms by the microscope had revealed all 

 the details of Venti'iculite structure ; and a careful comparison with Mr. Toulmin 

 Smith's descriptions and specimens had resulted in the identification of those examined 

 with some four of Mr. Smith's species; thus Scyphia tessellata was shown to be 

 equivalent to Ventriculites tessellatus (or, more correctly, V. texturatu%), Forospongia 

 ocellata to V. cavatus, and other unnamed forms to V. qidncuncialis and V. mam- 

 millaris respectively. The occurrence of ventriculite-structure in coprolitic material 

 presents a favourable opportunity for a fresh inquiry into its nature ; accordingly the 

 author described the minute characters of the hexradiate elements of which the 

 skeleton is composed, and the combinations of these hexradiates with one another. 

 A.bnormalities occur sometimes by the hexradiates becoming heptoradiate or pentara- 

 diate, and sometimes by some of their rays bending quite away from their normal 

 course. The whole of the skeleton fibre is distinctly tubular. Since the "V"entriculite 

 fibres have now been found fossilized in chalk, flint, and calcic phosphate, there can 

 be little doubt that they were keratose, and not siliceous in their nature. If this be 

 so, we have a diff'erence between Vitrea and Ventriculitidae of ordinal value at least, 

 and we must look for allies to the Ventriculites among the horny sponges. Verongia, 

 resembles Ventriculites in the single hollow cavity of its fibre and the non-spiculate 

 character of its skeleton ; Darwinella offers a resemblance in its hexradiate horny 

 spicules, and Spongionella in the regular arrangement of its fibres. These three 

 genera are indices of the directions in which the Keratosa tended to vary. At a very 



