MOLLUSCA (except CEPHALOPODA). 133 



shells from the Gault clay of Eolkestone, of Black Ven, Gallery 

 Charmouth, and of Okeford Fitzpaine also in Dorset, all VIII. 

 which are on the other side of the Case. Among the 

 Gastropods the Aporrhaidse with their winged lips and the 

 Scalariid?e with their transverse ribs furnish the most 

 striking forms. Among Lamellibranchs one may notice 

 species of Actinoceramus (Fig. 71 l), Trigonia, Cumllsea, 

 Liojnstha [Thetis], Thracia, Pinna, Ferna, and Pi'-otocardia. 



During the Aptian age was deposited the Lower Green- Table-case 

 sand of Hythe, Sandgate, and Faringdon. Here are casts 8. 

 of the borings made by Lithodonms and Pholas. Plcuroto- 

 maria gigantea, Alcctryonia niacroptera, and Toucasia Lons- 

 dalei are noteworthy forms. The last is a representative of 

 the Diceratida3 (see p. 143). 



The Barremian or Urgonian age is represented in the Table-case 

 South of England by the marine Atherfield Clay of the Isle 8. 

 of Wight and the brackish- water Punfield Beds of Dorset, 

 both of which belong to its lower division. Exogyra 

 simtata was then a common oyster ; among the shells 

 exhibited one has been cut through to show its great 

 thickness in old age. The lonsj-hinf?ed Perna Midleti occurs 

 in quantities in a special layer at Atherfield. Here are also 

 shown the elongate Gervillia anceps, with species of Trigonia, 

 Spliaera, Protocardia, Gyprina, and Astarte, and, among the 

 Gastropods, Ceratosiphon [Ap)orr]iais\ Fittoni, and Vicarya 

 Fizcuetana. 



Next come fossils from various rocks in the east of ipa^ie-case 

 England: the Speeton Clay of Yorkshire, the Tealby a 

 Series, and Claxby Ironstone, of Lincolnshire, all which 

 correspond partly to the Barremian and partly to the preced- 

 ing Neocomian Age. Among the more interesting lamel- 

 libranchs are Exogyra suhsimtata ( = E. Couloni), Trigonia 

 ingens, and the large Camptonectes [Pccten'] cinctas from 

 the Claxby Ironstone and Cucullaea donningtonensis. The 

 Lincolnshire formations run over into the next Case, and 

 are followed by fossils from the Wealden of Sussex and the ""'""g^ 

 Isle of Wight. The name Wealden is applied to a series 

 of freshwater and estuarine formations deposited mainly 

 during the Neocomian Age, and perhaps beginning at 

 the end of the Jurassic Epoch. The river-shells include 

 examples of Unio, of which the largest are the IT. valdensis 

 from Sussex and the Isle of Wight. In the middle of the 

 Gallery is a polished slab of Petworth or Sussex Marble, 

 composed of the shells of a freshwater snail, Viviparus 



Table-case 



