THE INDIGENOUS FAUNA. 19 



comian species both at Speeton and Atherfield in England, and on 

 the continent. But the Belemnites {B. pistilliformis and B. suh- 

 quadratus) are commoner in lower zones (Middle and Lower 

 Neocomian) at Tealby and Speeton. The new species B. Upwaren- 

 sis is a very remarkable form. 



Ancyloceras Hillsii, Sby. is characteristic of the Hythe beds in 

 the south of England. 



Specimens are rare of all the species of Cephalopoda, and they 

 are somewhat more fragmentary than is the case with the other 

 groups. The Belemnite guards preserve their original structures 

 of fibrous carbonate of lime^ and their upper ends present the 

 powdery, decomposed appearance and the successive off-shellings 

 of the subgenus Actinocamax. The Ammonite shells are changed 

 into crystalline calcite, with one exception, which is a mould in 

 yellowish sandstone. Only one Cephalopod is known from Brick- 

 hill, namely Belemnites suhquadratus. 



Of Gasteropoda there are 16 species, six of them being small 

 turbinated shells, prettily ornamented with ribs and granules. 

 Most of the univalves are undescribed species, and consequently of 

 little value in stratigraphical comparisons. The Pleurotomaria 

 gigantea is however a well-known shell in the Hythe beds of the 

 Wealden area, and in the Isle of Wight Greensand ; and the large 

 Nerincea shells are of interest as recalling the French Neocomian 

 types. All the shells are now made up of crystalline calcite with 

 the exception of the large Pleurotomaria, which is an inside cast in 

 coarse sandstone. 



At Brickhill no gasteropodous shell is known, but the markings 

 of a species of Trochus (?) are found impressed in the base of a 

 polyzoon, Multicreseis Michelini. 



Amongst the 54 species of Lamellihranchiata the Ostreidce are 

 conspicuous, as presenting the most striking forms and being the 

 most numerous in individuals. Such are Ostrea frons, var. 

 macroptera, Pecten orbicularis, var. magnus, Neithea ornithopus, 

 Kpng. and the little Plicatula Garter oniana. 



The great resemblance of the Up ware oysters to those of the 

 Jurassic rocks is very remarkable. A large expanded Gryphoid 



1 At Potton specimens occur changed into peroxide of iron. 



2—2 



